,cambridge ,natural ,science ,manuals4 ,,biological ,,series4 ,,general ,,editor3--,,arthur ,e4 ,,shipley1 ,m4,a4 ,,fellow ,,and ,,tutor ,,of ,,christ',s ,,college1 ,,cambridge4 ,,fossil ,,plants4 ,london3 ,c4 ,j4 ,,clay ,,and ,,sons1 ,,cambridge ,,university ,,press ,,warehouse1 ,,ave ,,maria ,,lane1 ,,and ,h4 ,k4 ,,lewis1 #acf1 ,,gower ,,street1 ,w4,c4 ,illustration ,glasgow3 #bfc1 ,,argyle ,,street4 ,leipzig3 ,f4 ,a4 ,,brockhaus4 ,new ,york3 ,,the ,,macmillan ,,company4 ,bombay3 ,e4 ,,seymour ,,hale4 ,illustration3 ,,tree ,,stumps ,,in ,a ,,carboniferous ,,forest4 ,,victoria ,,park1 ,,glasgow4 ,,fossil ,,plants ,,for ,,students ,,of ,,botany ,,and ,,geology ,,by ,a4 ,c4 ,,seward1 ,m4,a41 ,f4,g4,s4 ,,st ,,john',s ,,college1 ,,cambridge1 ,,lecturer ,,in ,,botany ,,in ,,the ,,university ,,of ,,cambridge4 ,,with ,,illustrations4 ,,vol4 ,i4 ,,cambridge3 ,,at ,,the ,,university ,,press4 #ahih ,all ,rights reserved4 ,cambridge3 ,,printed ,,by ,j4 ,,and ,c4 ,f4 ,,clay1 ,,at ,,the ,,university ,,press4 ,,preface4 ,in acceding to ,mr ,shipley's request to write a book on ,fossil ,plants for the ,cambridge ,natural ,history ,series1 ,i am well aware that ,i have undertaken a work which was considered too serious a task by one who has been called a 8founder of modern ,palaeobotany40 ,i owe more than ,i am able to express to the friendship and guidance of the late ,professor ,williamson2 and that ,i have attempted a work to which he consistently refused to commit himself1 requires a word of explanation4 ,my excuse must be that ,i have endeavoured to write a book which may render more accessible to students some of the important facts of ,palaeobotany1 and suggest lines of investigation in a subject which ,williamson had so thoroughly at heart4 ,the subject of ,palaeobotany does not readily lend itself to adequate treatment in a work intended for both geological and botanical students4 ,the ,botanist and ,geologist are not always acquainted with each other's subject in a sufficient degree to appreciate the significance of ,palaeobotany in its several points of contact with ,geology and recent ,botany4 ,i have endeavoured to bear in mind the possibility that the following pages may be read by both non-geological and non-botanical students4 ,it needs but a slight acquaintance with ,geology for a ,botanist to estimate the value of the most important applications of ,palaeobotany2 on the other hand1 the bearing of fossil plants on the problems of phylogeny and descent cannot be adequately understood without a fairly intimate knowledge of recent ,botany4 ,the student of elementary geology is not as a rule required to concern himself with vegetable palaeontology1 beyond a general acquaintance with such facts as are to be found in geological text-books4 ,the advanced student will necessarily find in these pages much with which he is already familiar2 but this is to some extent unavoidable in a book which is written with the dual object of appealing to ,botanists and ,geologists4 ,while considering those who may wish to extend their botanical or geological knowledge by an acquaintance with ,palaeobotany1 my aim has been to keep in view the requirements of the student who may be induced to approach the subject from the standpoint of an original investigator4 ,as a possible assistance to those undertaking research in this promising field of work1 ,i have given more references than may seem appropriate to an introductory treatise1 and there are certain questions dealt with in greater detail than an elementary treatment of the subject requires4 ,in several instances references are given in the text or in footnotes to specimens of ,coal-,measure plants in the ,williamson cabinet of microscopic sections4 ,now that this invaluable collection of slides has been acquired by the ,trustees of the ,british ,museum1 the student of ,palaeobotany has the opportunity of investigating for himself the histology of ,palaeozoic plants4 ,my plan has been to deal in some detail with certain selected types1 and to refer briefly to such others as should be studied by anyone desirous of pursuing the subject more thoroughly1 rather than to cover a wide range or to attempt to make the list of types complete4 ,of late years there has been a much wider interest evinced by ,botanists in the study of fossil plants1 and this is in great measure due to the valuable and able work of ,graf zu ,solms-,laubach4 ,his ,einleitung in die ,palaeophytologie must long remain a constant book of reference for those engaged in palaeobotanical work4 ,while referring to authors who have advanced the study of petrified plants of the ,coal period1 one should not forget the valuable services that have been rendered by such men as ,butterworth1 ,binns1 ,wilde1 ,earnshaw1 ,spencer1 ,nield1 ,lomax and ,hemingway1 by whose skill the specimens described by ,williamson and others were first obtained and prepared for microscopical examination4 ,i am indebted to many friends1 both ,british and ,continental1 for help of various kinds4 ,i would in the first place express my thanks to ,professor ,t4 ,mc,kenny ,hughes for having originally persuaded me to begin the study of recent and fossil plants4 ,i am indebted to ,prof4 ,nathorst of ,stockholm1 ,dr ,hartz of ,copenhagen1 ,prof4 ,zeiller1 ,dr ,renault and ,prof4 ,munier-,chalmas of ,paris1 ,prof4 ,bertrand of ,lille1 ,prof4 ,stenzel and the late ,prof4 ,roemer of ,breslau1 ,dr ,sterzel of ,chemnitz1 the late ,prof4 ,weiss of ,berlin1 the late ,dr ,stur of ,vienna1 and other continental workers1 as well as to ,mr ,knowlton of ,washington1 for facilities afforded me in the examination of fossil plant collections4 ,my thanks are due to the members of the ,geological and ,botanical departments of the ,british ,museum2 also to ,mr ,e4 ,t4 ,newton of the ,geological ,survey1 and to those in charge of various provincial museums1 for their never-failing kindness in offering me every assistance in the investigation of fossil plants under their charge4 ,prof4 ,marshall ,ward has given me the benefit of his criticism on the section dealing with ,fungi2 and my friend ,mr ,alfred ,harker has rendered me a similar service as regards the chapter on ,geological ,history4 ,i am especially grateful to my colleague1 ,mr ,francis ,darwin1 for having read through the whole of the proofs of this volume4 ,to ,mr ,shipley1 as ,editor1 ,i am under a debt of obligation for suggestions and help in various forms4 ,i would also express my sense of the unfailing courtesy and skill of the staff of the ,university ,press4 ,my friend ,mr ,kidston of ,stirling has always generously responded to my requests for the loan of specimens from his private collection4 ,prof4 ,bayley ,balfour of ,edinburgh1 ,mr ,wethered of ,cheltenham and others have assisted me in a similar manner4 ,i would also express my gratitude to ,dr ,hoyle of ,manchester1 ,mr ,platnauer of ,york1 and ,mr ,rowntree of ,scarborough for the loan of specimens4 ,to ,dr ,henry ,woodward of the ,british ,museum ,i am indebted for the loan of the woodblocks made use of in figs4 #aj1 #dg1 #fj1 #ff1 and #aja1 and to ,messrs ,macmillan for the process-block of fig4 #be4 ,for the photographs reproduced in figs4 #ae1 #cd1 #fh1 #ajb and #ajc ,i owe an acknowledgment to ,mr ,edwin ,wilson of ,cambridge1 and to my friend ,mr ,c4 ,a4 ,barber for the micro-photograph made use of in fig4 #dj4 ,in conclusion ,i wish more particularly to thank my wife1 who has drawn by far the greater number of the illustrations1 and has in many other ways assisted me in the preparation of this ,volume4 ,in ,volume ,,ii the ,systematic treatment of ,plants will be concluded1 and the last chapters will be devoted to such subjects as geological floras1 plants as rock-builders1 fossil plants and evolution1 and other general questions connected with ,palaeobotany4 ,a4 ,c4 ,,seward4 ,,botanical ,,laboratory1 ,,cambridge4 ,march1 #ahih4 ,,table ,,of ,,contents4 ,,part ,i4 ,,general4 ,,chapter ,i4 ,,historical ,,sketch4 ,pp4 #a-aa4 ,fossil plants and the ,flood4 ,sternberg and ,brongniart4 ,the internal structure of fossil plants4 ,english ,palaeobotanists4 ,difficulties of identification4 ,,chapter ,,ii4 ,,relation ,,of ,,palaeobotany ,,to ,,botany ,,and ,,geology4 ,pp4 #ab-ba4 ,neglect of fossils by ,botanists4 ,fossil plants and distribution4 ,fossil plants and climate4 ,fossil plants and phylogeny4 ,,chapter ,,iii4 ,,geological ,,history4 ,pp4 #bb-ec4 ,rock-building4 ,calcareous rocks4 ,geological sections4 ,inversion of strata4 ,table of ,strata3 ,i4 ,archaean1 #cd-cf4 ,,ii4 ,cambrian1 #cf-cg4 ,,iii4 ,ordovician1 #cg-ch4 ,,iv4 ,silurian1 #ch4 ,v4 ,devonian1 #ci4 ,,vi4 ,carboniferous1 #ci-de4 ,,vii4 ,permian1 #de-dg4 ,,viii4 ,trias41 #dg-dh4 ,,ix4 ,jurassic1 #dh-di4 ,x4 ,cretaceous1 #ej-ea4 ,,xi4 ,tertiary1 #ea-ec4 ,geological ,evolution4 ,,chapter ,,iv4 ,,the ,,preservation ,,of ,,plants ,,as ,,fossils4 ,pp4 #ed-ib4 ,old surface-soils4 ,fossil wood4 ,conditions of fossilisation4 ,drifting of trees4 ,meaning of the term #8,fossil4' ,incrustations4 ,casts of trees4 ,fossil casts4 ,plants and coal4 ,fossils in half-relief4 ,petrified trees4 ,petrified wood4 ,preservation of tissues4 ,coal-balls4 ,fossil nuclei4 ,fossil plants in volcanic ash4 ,conditions of preservation4 ,,chapter ,v4 ,,difficulties ,,and ,,sources ,,of ,,error ,,in ,,the ,,determination ,,of ,,fossil ,,plants4 ,pp4 #ic-aji4 ,external resemblance4 ,venation characters4 ,decorticated stems4 ,imperfect casts4 ,mineral deposits simulating plants4 ,traces of wood-borers in petrified tissue4 ,photography and illustration4 ,,chapter ,,vi4 ,,nomenclature4 ,pp4 #aaj-aae4 ,rules for nomenclature4 ,the rule of priority4 ,terminology and convenience4 ,,part ,,ii4 ,,systematic4 ,,chapter ,,vii4 ,,thallophyta4 ,pp4 #aaf-bbh4 ,,page ,i4 ,,peridiniales #aag-aah ,,ii4 ,,coccospheres ,,and ,,rhabdospheres #aah-aba ,,iii4 ,,schizophyta #aba-ach ,a4 ,,schizophyceae 7,,cyanophyceae7 #abb-acb ,girvanella #abd-abf4 ,borings in shells #abg-abi4 ,zonatrichites #abi-acj4 ,b4 ,,schizomycetes 7,,bacteria7 #acb-ach ,bacillus ,permicus #ace-acf4 ,b4 ,tieghemi and ,micrococcus ,guignardi #acf4 ,fossil ,bacteria #acg-ach4 ,,iv4 ,,algae #ach-bje ,scarcity of fossil algae4 ,fossils simulating ,algae4 ,recognition of fossil algae4 ,algites c4 ,a4 ,,diatomaceae #aej-aef ,recent ,diatoms4 ,fossil ,diatoms4 ,bactryllium c4 ,b4 ,,chlorophyceae #aef-agh a4 ,,siphoneae #aeg-agg 4 ,caulerpaceae #aeg-aei 4 ,codiaceae #aei-afd ,codium #aei-afj4 ,sphaerocodium #afj4 ,penicillus #afa4 ,ovulites #afa-afd4 ,halimeda #afd4 4 ,dasycladaceae #afd-agg ,acetabularia #afe-aff4 ,acicularia #aff-afi4 ,cymopolia #afi-aga4 ,vermiporella #agb-agc4 ,sycidium #agc4 ,diplopora #agd-age4 ,gyroporella #age4 ,dactylopora1 ,palaeozoic and ,mesozoic ,siphoneae #age-agg4 b4 ,,confervoideae #agg-agh ,c4,,incertae ,,sedis #agh-ahc ,boghead #8,coal4' ,reinschia #ahj-aha4 ,pila #aha-ahb4 ,d4 ,,rhodophyceae #ahc-aij ,,corallinaceae #ahc-aij ,lithothamnion #ahe-ahi4 ,solenopora #ahi-aij4 ,e4 ,,phaeophyceae #aia-bjb ,nematophycus #aib-bjb ,pachytheca #bjb-bjd ,algites #bjd-bje ,v4 ,,myxomycetes 7,,mycetozoa7 #bje-bjf ,myxomycetes ,mangini #bjf4 ,,vi4 ,,fungi #bjg-bbb ,,ascomycetes4 ,,basidiomycetes4 ,pathology of fossil tissues4 ,oochytrium ,lepidodendri #baf-bag4 ,peronosporites antiquarius #bag-bbj4 ,cladosporites bipartitus #bbj4 ,haplographites cateniger #bbj4 ,zygosporites #bbj-bba4 ,polyporus vaporarius #bba4 ,,vii4 ,,charophyta #bbb-bbh ,,chareae #bbc-bbh ,chara #bbe-bbh4 ,c4 ,bleicheri #bbf4 ,c4 ,knowltoni #bbf-bbg4 ,c4 ,wrighti #bbg4 ,,chapter ,,viii4 ,,bryophyta4 ,pp4 #bbi-bda4 ,i4 ,,hepaticae #bcj-bcf ,marchantites #bcc-bce4 ,m4 ,sezannensis #bcd-bce4 ,,ii4 ,,musci #bcf-bda ,muscites #bch-bda4 ,m4 polytrichaceus #bci-bdj4 ,palaeozoic ,mosses4 ,muscites ferrugineus #bda4 ,,chapter ,,ix4 ,,pteridophyta 7,,vascular ,,cryptograms74 ,pp4 #bdb-bid4 ,i4 ,,equisetales 7,,recent7 #bdd-bed ,,equisetaceae #bdd-bed ,equisetum #bdf-bed4 ,,ii4 ,,fossil ,,equisetales #bed-bid ,a4 ,,equisetites #beg-bha ,equisetites ,hemingwayi #bfc-bfd4 ,e4 spatulatus #bfd-bff4 ,e4 zeaeformis #bff4 ,e4 arenaceus #bfh-bfi4 ,e4 columnaris #bfi-bgj4 ,e4 ,beani #bgj-bge4 ,e4 lateralis #bge-bgi4 ,e4 ,burchardti #bgi-bhj4 ,b4 ,,phyllotheca #bha-bia ,phyllotheca deliquescens #bhc-bhd4 ,p4 ,brongniarti #bhf-bhg4 ,p4 indica and ,p4 australis #bhg-bhi4 ,c4 ,,schizoneura #bia-bid ,s4 gondwanensis #bib-bic4 ,,chapter ,x4 ,,equisetales 7continued74 ,pp4 #bie-chh4 ,d4 ,,calamites #bie-chc ,i4 ,historical sketch #bie-cjb ,,ii4 ,description of the anatomy of ,calamites #cjb-cfd a4 ,stems #cjd-cbi ,arthropitys1 ,arthrodendron1 and ,calamodendron4 b4 ,leaves #cbi-cdb 4 ,calamocladus 7,asterophyllites7 #ccb-ccf4 ,c4 equisetiformis #cce-ccf4 4 ,annularia #ccf-cdb4 ,a4 stellata #cch-cdj4 ,a4 sphenophylloides #cda-cdb4 c4 ,roots #cdb-cdi d4 ,cones #cdi-cfe ,calamostachys ,binneyana #cea-cee4 ,c4 ,casheana #cee-ceg4 ,palaeostachya vera #ceh-cfj4 ,calamostachys1 ,palaeostachya and ,macrostachya #cfa-cfd4 ,,iii4 ,pith-casts of ,calamites #cfe-chj ,calamitina #cfg-cgd4 ,calamites 7,calamitina7 ,gpperti #cgb-cgd4 ,stylocalamites #cgd-cgf4 ,c4 7,stylocalamites7 ,suckowi #cgd-cgf4 ,eucalamites #cgf-cgi4 ,c4 7,eucalamites7 cruciatus #cgh-cgi4 ,,iv4 ,conclusion #cha-chc ,e4 ,,archaeocalamites #chc-chh ,a4 scrobiculatus #chf-chg4 ,,chapter ,,xi4 ,,sphenophyllales4 ,pp4 #chi-dad4 ,i4 ,,sphenophyllum #chi-dad ,a4 ,the anatomy of ,sphenophyllum #cib-djf a4 ,stems #cib-cih ,sphenophyllum insigne and ,s4 plurifoliatum #cig-cih4 b4 ,roots #cii c4 ,leaves #cii d4 ,cones #dja-djf ,sphenophyllostachys ,dawsoni #djb-dje4 ,s4 ,rmeri #dje-djf4 ,b4 ,types of vegetative ,branches of ,sphenophyllum #djg-dab ,sphenophyllum emarginatum #djg-djh4 ,s4 trichomatosum #djh-dji4 ,s4 ,thoni #daj-daa4 ,s4 speciosum #daa-dab4 ,c4 ,affinities1 ,range and ,habit of ,sphenophyllum #dab-dad ,,list ,,of ,,illustrations4 ,,frontispiece4 ,,tree ,,stumps ,,in ,a ,,carboniferous ,,forest4 ,drawn from a photograph4 7,m4 ,seward47 ,,page #eg4 ,,fig4 ,,page #a4 ,lepidodendron4 7,m4 ,s47 #aj #b4 ,geological section #bi #c4 ,table of strata #cb1 #cc #d4 ,geological section 7coal seam7 #dd #e4 ,neuropteris ,scheuchzeri ,hoffm4 7,m4 ,s47 #de #f4 ,submerged ,forest at ,leasowe4 7,m4 ,s47 #ei #g4 ,ammonite on coniferous wood4 7,m4 ,s47 #fa #h4 ,coniferous wood in flint4 7,m4 ,s47 #fb #i4 ,bored fossil wood4 7,m4 ,s47 #fb #aj4 ,section of an old pool filled up with a mass of ,chara4 7,from block lent by ,dr ,woodward7 #fi #aa4 ,equisetites columnaris ,brongn4 7,m4 ,s47 #gb #ab4 ,stigmaria ficoides ,brongn4 7,m4 ,s47 #gc #ac4 ,cordaites etc4 in coal4 7,m4 ,s47 #gf #ad4 ,crystallisation in petrified tissues #ha #ae4 ,lepidodendron4 7,from a photograph by ,mr ,edwin ,wilson of a specimen lent by ,mr ,kidston7 #hb #af4 ,cast of a fossil cell4 7,m4 ,s47 #hd #ag4 ,calcareous nodule from the ,coal-,measures #he #ah4 ,lepidodendron from ,arran4 7,m4 ,s47 #hi #ai4 ,trigonocarpon seeds in a block of sandstone4 7,m4 ,s47 #ia #bj4 ,restio1 ,equisetum1 ,casuarina and ,ephedra4 7,m4 ,s47 #ie #ba4 ,polygonum equisetiforme ,sibth4 and ,sm4 7,m4 ,s47 #if #bb4 ,kaulfussia sculifolia ,blume4 7,m4 ,s47 #ig #bc4 ,a branched ,lepidodendroid stem 7,knorria mirabilis ,ren4 and ,zeill474 7,m4 ,s47 #ajb #bd4 ,partially disorganised petrified tissue #ajg #be4 ,coccospheres and ,rhabdospheres4 7,lent by ,messrs ,macmillan7 #aai #bf4 ,girvanella problematica ,eth4 and ,nich4 7,m4 ,s47 #abd #bg4 ,fish-scale and shell perforated by a boring organism4 7,m4 ,s47 #abh #bh4 ,bacillus ,tieghemi ,ren4 and ,micrococcus ,guignardi ,ren4 7,m4 ,s47 #ace #bi4 ,laminaria sp4 #adj #cj4 ,rill-mark2 trail of a seaweed2 tracks of a ,polychaet4 7,m4 ,s47 #adc #ca4 ,chondrites verisimilis ,salt4 7,m4 ,s47 #adf #cb4 ,lithothamnion mamillosum ,gmb42 ,sycidium melo ,sandb42 ,bactryllium deplanatum ,heer2 ,calcareous pebble from a lake in ,michigan4 7,m4 ,s47 #aee #cc4 ,cymopolia barbata 7,l472 ,acicularia ,andrussowi ,solms2 ,acicularia sp42 ,a4 ,schencki 7,mb472 ,a4 ,mediterranea ,lamx42 ,ovulites margaritula ,lamx42 ,penicillus pyramidalis 7,lamx47 7,m4 ,s47 #afb #cd4 ,acetabularia mediterranea ,lamx4 7,photograph by ,mr ,edwin ,wilson7 #afe #ce4 ,diplopora2 ,gyroporella2 ,penicillus2 ,ovulites margaritula ,lam42 ,confervites chantransioides 7,born47 #agd #cf4 ,torbanite2 ,pila bibractensis and ,reinschia australis #ahj #cg4 ,lithothamnion sp42 ,l4 suganum ,roth42 ,sphaerocodium ,bornemanni ,roth4 #ahf #ch4 ,solenopora compacta 7,billings74 7,m4 ,s47 #ahi #ci4 ,nematophycus ,logani 7,daws47 #aif #dj4 ,nematophycus ,storriei ,barb4 7,photograph by ,mr ,c4 ,a4 ,barber7 #aii #da4 ,cells of ,cycadeoidea gigantea ,sew41 ,osmundites ,dowkeri ,carr and ,memecylon with vacuolated contents2 ,peronosporites antiquarius ,smith2 ,zygosporites #bad #db4 ,tracheids of coniferous wood attacked by ,trametes radiciperda ,hart and ,agaricus melleus ,vahl4 #bae #dc4 ,oochytrium ,lepidodendri ,ren42 ,polyporus vaporarius ,fr4 var4 succinea2 ,cladosporites bipartitus ,fel42 ,haplographites cateniger ,fel4 7,m4 ,s47 #bag #dd4 ,cells of fossil plants with fungal hyphae #bai #de4 ,chara ,knowltoni ,sew42 ,chara foetida ,a4 ,br4 7,a and ,b1 ,mr ,highley2 ,c-,e1 ,m4 ,s47 #bbd #df4 ,chara ,bleicheri ,sap42 ,chara8 sp42 ,c4 ,wrighti ,forbes4 7,m4 ,s47 #bbf #dg4 ,chara ,knowltoni ,sew4 7,from block lent by ,dr ,woodward7 #bbg #dh4 ,tristichia hypnoides ,spreng42 ,podocarpus cupressina ,br4 and ,ben42 ,selaginella ,oregana ,eat4 7,m4 ,s47 #bca #di4 ,marchantites erectus 7,leck47 7,m4 ,s47 #bcc #ej4 ,marchantites ,sezannensis ,sap4 7,m4 ,s47 #bce #ea4 ,muscites polytrichaceus ,ren4 and ,zeill4 7,m4 ,s47 #bci #eb4 ,equisetum maximum ,lam42 ,e4 arvense ,l4 #bdf #ec4 ,equisetum palustre ,l4 7,m4 ,s47 #bdg #ed4 ,plan of the vascular bundles in an ,equisetum stem2 ,e4 arvense ,l4 #bej #ee4 ,equisetum variegatum ,schl42 ,e4 maximum ,lam4 #beb #ef4 ,calamitean leaf-sheath4 7,m4 ,s47 #bfj #eg4 ,equisetites ,hemingwayi ,kidst4 7,mr ,highley7 #bfb #eh4 ,equisetites spatulatus ,zeill42 ,e4 zeaeformis 7,schloth472 ,equisetites lateralis ,phill42 ,equisetites columnaris ,brongn42 ,equisetum trachyodon ,a4 ,br4 7,m4 ,s47 #bfe #ei4 ,equisetites platyodon ,brongn4 7,m4 ,s47 #bfg #fj4 ,equisetites ,beani 7,bunb474 7,from a block lent by ,dr ,woodward7 #bga #fa4 ,equisetites ,beani 7,bunb474 7,m4 ,s47 #bgb #fb4 ,e4 ,beani 7,bunb474 7,m4 ,s47 #bgd #fc4 ,e4 lateralis ,phill4 7,m4 ,s47 #bge #fd4 ,e4 lateralis ,phill4 7,m4 ,s47 #bgh #fe4 ,e4 ,burchardti ,dunk4 7,m4 ,s47 #bgi #ff4 ,e4 ,yokoyamae ,sew4 7,from a block lent by ,dr ,woodward7 #bhj #fg4 ,phyllotheca8 sp4 7,from a photograph by ,mr ,edwin ,wilson7 #bhe #fh4 ,phyllotheca ,brongniarti ,zigno2 ,p4 indica ,bunb42 ,calamocladus frondosus ,grand',eury4 7,m4 ,s47 #bhg #fi4 ,schizoneura gondwanensis ,feist4 7,m4 ,s47 #bic #gj4 ,transverse section of a ,calamite stem4 7,m4 ,s47 #bii #ga4 ,transverse section of a young ,calamite stem #cje #gb4 ,longitudinal and transverse sections of ,calamites #cjh #gc4 ,transverse section of a ,calamite stem #caj #gd4 ,transverse section of ,calamites 7,arthropitys7 sp4 #cab #ge4 ,longitudinal section 7tangential7 of ,calamites 7,arthropitys7 sp4 #cac #gf4 ,longitudinal section 7tangential7 of ,calamites 7,arthropitys7 sp4 #cad #gg4 ,portion of a ,calamite stem2 partially restored4 7,m4 ,s47 #caf #gh4 ,transverse and longitudinal 7radial7 sections of a thick #cah #gi4 ,calamite stem4 7,mr ,highley7 #cai #hj4 ,transverse section of a ,calamite showing callus wood #cbj #ha4 ,longitudinal section of a young ,calamite #cba #hb4 ,pith-casts of ,calamites 7,stylocalamites7 sp4 7,m4 ,s47 #cbc #hc4 ,calamites 7,arthrodendron7 sp4 ,transverse and longitudinal sections #cbg #hd4 ,transverse section of ,calamites 7,calamodendron7 intermedius ,ren4 #cbh #he4 ,leaves of a ,calamite4 7,m4 ,s47 #ccj #hf4 ,transverse section of a ,calamite leaf #cca #hg4 ,calamocladus equisetiformis 7,schloth47 7,miss ,g4 ,m4 ,woodward7 #ccd #hh4 ,annularia stellata 7,schloth47 7,m4 ,s47 #cci #hi4 ,annularia sphenophylloides ,zenk4 7,m4 ,s47 #cdj #ij4 ,pith-cast of a ,calamite1 with roots4 7,m4 ,s47 #cdc #ia4 ,transverse sections of ,calamite roots #cde #ib4 ,root given off from a ,calamite stem #cdg #ic4 ,calamostachys sp4 7,m4 ,s47 #cej #id4 ,c4 ,binneyana 7,carr474 7,mr ,highley7 #ceb #ie4 ,c4 ,binneyana 7,carr47 #ced #if4 ,c4 ,casheana ,will4 #cef #ig4 ,palaeostachya pedunculata ,will4 7,m4 ,s47 #ceg #ih4 ,p4 vera sp4 nov4 #cei #ii4 ,calamites 7,calamitina7 ,gpp4 7,ett47 7,m4 ,s47 #cfh #ajj4 ,calamites 7,calamitina7 approximatus ,brongn4 ,from a photograph by ,mr ,kidston #cgj #aja4 ,calamites 7,calamitina7 sp4 7,from a block lent by ,dr ,woodward7 #cgc #ajb4 ,calamites 7,eucalamites7 cruciatus ,sternb4 7,from a photograph by ,mr ,edwin ,wilson7 #cgg #ajc4 ,archaeocalamites scrobiculatus 7,schloth474 7,from a photograph by ,mr ,edwin ,wilson7 #che #ajd4 ,diagrammatic longitudinal section of ,sphenophyllum #cic #aje4 ,transverse and longitudinal sections of ,sphenophyllum insigne 7,will47 and ,s4 plurifoliatum ,will4 and ,scott #cid #ajf4 ,sphenophyllum plurifoliatum ,will4 and ,scott4 7,from a photograph by ,mr ,highley7 #cih #ajg4 ,sphenophyllum strobilus1 stem and root #djj #ajh4 ,diagrammatic longitudinal section of a ,sphenophyllum strobilus4 7,m4 ,s47 #djb #aji4 ,sphenophyllum emarginatum 7,brongn47 7,m4 ,s47 #djg #aaj4 ,sphenophyllum ,thoni ,mahr42 ,s4 trichomatosum ,stur4 7,m4 ,s47 #daj #aaa4 ,sphenophyllum speciosum 7,royle74 7,m4 ,s47 #daa ,note4 ,the references in the footnotes require a word of explanation4 ,the titles of the works referred to will be found in the ,bibliography at the end of the volume4 ,in this list the authors' names are arranged alphabetically and the papers of each author are in chronological order4 ,the numbers in brackets after the author's name in the footnotes1 and before his name in the bibliographical list1 refer to the year of publication4 ,except in cases where the works were published prior to #ahjj1 the first two figures are omitted3 thus ,ward 7#hd7 refers to a paper published by ,l4 ,f4 ,ward in #ahhd4 ,this system was suggested by ,dr ,h4 ,h4 ,field in the ,biologisches ,centralblatt1 vol4 ,,xiii4 #ahic1 p4 #gec4 7,ueber die ,art der ,abfassung naturwissenschaftlicher ,litteraturverzeichnisse47 ,,part ,i4 ,,general4 ,,chapter ,i4 ,,historical ,,sketch4 8,but particular care ought to be had not to consult or take relations from any but those who appear to have been both long conversant in these affairs1 and likewise persons of ,sobriety1 ,faithfulness and ,discretion1 to avoid the being misled and imposed upon either by falsehood1 or the ignorance1 credulity1 and fancifulness1 that some of these people are but too obnoxious unto40 ,,john ,,woodward1 #agbh4 ,the scientific study of fossil plants dates from a comparatively recent period1 and palaeobotany has only attained a real importance in the eyes of botanists and geologists during the last few decades of the present century4 ,it would be out of place1 in a short treatise like the present1 to attempt a detailed historical sketch1 or to give an adequate account of the gradual rise and development of this modern science4 ,an excellent ,sketch of ,palaeobotany has recently been drawn up by ,prof4 ,lester ,ward#a1 of the ,united ,states ,geological ,survey1 and an earlier historical retrospect may be found in the introduction to an important work by an eminent ,german palaeobotanist1 the late ,prof4 ,gppert#b4 ,in the well-known work by ,parkinson on ,the ,organic ,remains of a ,former ,world#c there is much interesting information as to the early history of our knowledge of fossil plants1 as well as a good exposition of the views held at the beginning of this century4 ,sidenote3 ,,fossil ,,plants ,,and ,,the ,,flood4 ,as a means of bringing into relief the modern development of the science of fossil plants1 we may briefly pass in review some of the earlier writers1 who have concerned themselves in a greater or less degree with a descriptive or speculative treatment of the records of a past vegetation4 ,in the early part of the present century1 and still more in the eighteenth century1 the occurrence of fossil plants and animals in the earth's crust formed the subject of animated1 not to say acrimonious1 discussion4 ,the result was that many striking and ingenious theories were formulated as to the exact manner of formation of fossil remains1 and the part played by the waters of the deluge in depositing fossiliferous strata4 ,the earlier views on fossil vegetables are naturally bound up with the gradual evolution of geological science4 ,it is from ,italy that we seem to have the first glimmering of scientific views2 but we are led to forget this early development of more than three hundred years ago1 when we turn to the writings of ,english and other authors of the eighteenth century4 8,under these white banks by the roadside10 as a writer on ,verona has expressed it1 8was born1 like a poor ,italian gipsy1 the modern science of geology40 ,early in the sixteenth century the genius of ,leonardo da ,vinci#d compelled him to adopt a reasonable explanation of the occurrence of fossil shells in rocks far above the present sea-level4 ,another ,italian writer1 ,fracastaro1 whose attention was directed to this matter by the discovery of numerous shells brought to light by excavations at ,verona1 expressed his belief in the organic nature of the remains1 and went so far as to call in question the ,mosaic deluge as a satisfactory explanation of the deposition of fossil-bearing strata4 ,the partial recognition by some observers of the true nature of fossils marks the starting point of more rational views4 ,the admission that fossils were not mere sports of nature1 or the result of some wonderful #8vis lapidifica1' was naturally followed by numerous speculations as to the manner in which the remains of animals and plants came to be embedded in rocks above the sea-level4 ,for a long time1 the #8universal flood' was held responsible by nearly all writers for the existence of fossils in ancient sediments4 ,dr ,john ,woodward1 in his ,essay toward a ,natural ,history of the ,earth1 propounded the somewhat revolutionary theory1 that 8the whole terrestrial globe was taken all to pieces and dissolved at the ,deluge1 the particles of stone1 marble1 and all solid fossils dissevered1 taken up into the water1 and there sustained together with sea-shells and other animal and vegetable bodies3 and that the present earth consists1 and was formed out of that promiscuous mass of sand1 earth1 shells1 and the rest falling down again1 and subsiding from the water#e40 ,in common with other writers1 he endeavoured to fix the exact date of the flood by means of fossil plants4 ,speaking of some hazel-nuts1 which were found in a ,cheshire moss pit1 he draws attention to their unripened condition1 and adds3 8,the deluge came forth at the end of ,may1 when nuts are not ripe40 ,as additional evidence1 he cites the occurrence of 8,pine cones in their vernal state10 and of some ,coal-,measure fossils which he compares with ,virginian ,maize1 8tender1 young1 vernal1 and not ripened#f40 ,woodward 7#affe-agbh7 was ,professor of ,physic in ,gresham ,college2 he bequeathed his geological collections to the ,university of ,cambridge1 and founded the ,chair which bears his name4 ,another writer1 ,mendes da ,costa1 in a paper in the ,philosophical ,transactions for #ageh1 speaks of the impressions of 8ferns and reed-like plants0 in the coal-beds1 and describes some fossils 7,sigillaria and ,stigmaria7 as probably unknown forms of plant life#g4 ,here we have the suggestion that in former ages there were plants which differed from those of the present age4 ,discussing the nature of some cones 7,lepidostrobi7 from the ironstone of ,coalbrookdale in ,shropshire1 he concludes3 8,i firmly believe these bodies to be of vegetable origin1 buried in the strata of the ,earth at the time of the universal deluge recorded by ,moses40 ,scheuchzer of ,zurich1 the author of one of the earliest works on fossil plants and a 8great apostle of the ,flood ,theory10 figures and describes a specimen as an ear of corn1 and refers to its size and general appearance as pointing to the month of ,may as the time of the deluge#h4 ,another ,english writer1 ,dr ,parsons1 in giving an account of the well-known #8fossil fruits and other bodies found in the island of ,sheppey1' is disposed to dissent from ,woodward's views as to the time of the flood4 ,he suggests that the fact of the ,sheppey fruits being found in a perfectly ripe condition1 points to the autumn as the more probable time for the occurrence of the deluge#i4 ,in looking through the works of the older writers1 and occasionally in the pages of latter-day contributors1 we frequently find curiously shaped stones1 mineral markings on rock surfaces1 or certain fossil animals1 described as fossil plants4 ,in ,plot's ,natural ,history of ,oxfordshire1 published in #agje1 a peculiarly shaped stone1 probably a flint1 is spoken of as one of the #8,fungi lethales non esculenti#aj'2 and again a piece of coral#aa is compared with a #8,bryony root broken off transversely4' ,on the other hand1 that we may not undervalue the painstaking and laborious efforts of those who helped to lay the foundations of modern science1 we may note that such authors as ,scheuchzer and ,woodward were not misled by the moss-like or dendritic markings of oxide of manganese on the surface of rocks1 which are not infrequently seen to-day in the cabinets of amateurs as specimens of fossil plants4 ,the oldest figures of fossil plants from ,english rocks which are drawn with any degree of accuracy are those of ,coal-,measure ferns and other plants in an important work by ,edward ,lhwyd published at ,oxford in #agfjab4 ,passing beyond these prescientific speculations1 brief reference may be made to some of the more eminent pioneers of palaeobotany4 ,the ,englishman ,artis#ac deserves mention for the quality rather than the quantity of his contributions to ,palaeozoic botany2 and among ,american authors ,steinhauer's#ad name must hold a prominent place in the list of those who helped to found this branch of palaeontology4 ,among ,german writers1 ,schlotheim stands out prominently as one who first published a work on fossil plants which still remains an important book of reference4 ,writing in #ahjd1 he draws attention to the neglect of fossils from a scientific standpoint2 they are simply looked upon1 he says1 as 8unimpeachable documents of the flood#ae40 ,his book contains excellent figures of many ,coal-,measure plants1 and we find in its pages occasional comparisons of fossil species with recent plants of tropical latitudes4 ,among the earlier authors whose writings soon become familiar to the student of fossil plants1 reference must be made to ,graf ,sternberg1 who was born three years before ,schlotheim1 but whose work came out some years later than that of the latter4 ,his great contribution to ,fossil ,botany entitled ,versuch einer geognostisch-botanischen ,darstellung der ,flora der ,vorwelt1 was published in several parts between the years #ahbj and #ahch2 it was drawn up with the help of the botanist ,presl1 and included a valuable contribution by ,corda#af4 ,in addition to descriptions and numerous figures of plants from several geological horizons1 this important work includes discussions on the formation of coal1 with observations on the climates of past ages4 ,sidenote3 ,,sternberg ,,and ,,brongniart4 ,sternberg endeavoured to apply to fossil plants the same methods of treatment as those made use of in the case of recent species4 ,about the same time as ,sternberg's earlier parts were published1 ,adolphe ,brongniart#ag of ,paris began to enrich palaeobotanical science by those splendid researches which have won for him the title of the 8,father of palaeobotany40 ,in ,brongniart's ,prodrome1 and ,histoire des vgtaux fossiles1 and later in his ,tableau des genres de vgtaux fossiles1 we have not merely careful descriptions and a systematic arrangement of the known species of fossil plants1 but a masterly scientific treatise on palaeobotany in its various aspects1 which has to a large extent formed the model for the best subsequent works on similar lines4 ,from the same author1 at a later date1 there is at least one contribution to fossil plant literature which must receive a passing notice even in this short sketch4 ,in #ahci he published an exhaustive account of the minute structure of one of the well-known ,palaeozoic genera1 ,sigillaria2 this is not only one of the best of the earliest monographs on the histology of fossil species1 but it is one of the few existing accounts of the internal structure of this common type#ah4 ,the fragment of a ,sigillarian stem which formed the subject of ,brongniart's memoir is in the ,natural ,history ,museum in the ,jardin des ,plantes1 ,paris4 ,it affords a striking example of the perfection of preservation as well as of the great beauty of the silicified specimens from ,autun1 in ,central ,france4 ,brongniart was not only a remarkably gifted investigator1 whose labours extend over a period connecting the older and more crude methods of descriptive treatment with the modern development of microscopic analysis1 but he possessed the power of inspiring a younger generation with a determination to keep up the high standard of the palaeobotanical achievements of the ,french ,school4 ,in some cases1 indeed1 his disciples have allowed a natural reverence for the ,master to warp their scientific judgement1 where our more complete knowledge has naturally led to the correction of some of ,brongniart's conclusions4 ,without attempting to follow the history of the science to more recent times1 the names of ,heer1 ,lesquereux1 ,zigno1 ,massalongo1 ,saporta and ,ettingshausen should be included among those who rendered signal service to the science of fossil plants4 ,the two ,swiss writers1 ,heer#ai and ,lesquereux#bj1 contributed numerous books and papers on palaeobotanical subjects1 the former being especially well known in connection with the fossil floras of ,switzerland and of ,arctic lands1 and the latter for his valuable writings on the fossil plants of his adopted country1 ,north ,america4 ,zigno#ba and ,massalongo#bb performed like services for ,italy1 and the ,marquis of ,saporta's name will always hold an honourable and prominent position in the list of the pioneers of scientific palaeobotany2 his work on the ,tertiary and ,mesozoic floras of ,france being specially noteworthy among the able investigations which we owe to his ability and enthusiasm#bc4 ,in ,baron ,ettingshausen#bd we have another representative of those students of ancient vegetation who have done so much towards establishing the science of fossil plants on a philosophical basis4 ,as in other fields of ,natural ,science1 so also in a marked degree in fossil botany1 a new stimulus was given to scientific inquiry by the application of the microscope to palaeobotanical investigation4 ,in #ahbh ,sprengel published a work entitled ,commentatio de ,psarolithis1 ligni fossilis genere#be2 in which he dealt in some detail with the well-known silicified fern-stems of ,palaeozoic age1 from ,saxony1 basing his descriptions on the characteristics of anatomical structure revealed by microscopic examination4 ,sidenote3 ,,the ,,internal ,,structure ,,of ,,fossil ,,plants4 ,in #ahcc ,henry ,witham of ,lartington brought out a work on ,the ,internal ,structure of ,fossil ,vegetables#bf2 this book1 following the much smaller and less important work by ,sprengel1 at once established palaeobotany on a firmer scientific basis1 and formed the starting point for those more accurate methods of research1 which have yielded such astonishing results in the hands of modern workers4 ,in the introduction ,witham writes1 8,my principal object in presenting this work to the public1 is to impress upon geologists the advantage of attending more particularly to the intimate organization of fossil plants2 and should ,i succeed in directing their efforts towards the elucidation of this obscure subject1 ,i shall feel a degree of satisfaction which will amply repay my labour#bg40 ,on another page he writes as follows1--8,from investigations made by the most active and experienced botanical geologists1 we find reason to conclude that the first appearance of an extensive vegetation occurred in the ,carboniferous series2 and from a recent examination of the mountain-limestone groups and coal-fields of ,scotland1 and the north of ,england1 we learn that these early vegetable productions1 so far from being simple in their structure1 as had been supposed1 are as complicated as the phanerogamic plants of the present day4 ,this discovery necessarily tends to destroy the once favourite idea1 that1 from the oldest to the most recent strata1 there has been a progressive development of vegetable and animal forms1 from the simplest to the most complex#bh40 ,since ,witham's day we have learnt much as to the morphology of ,palaeozoic plants1 and can well understand the opinions to which he thus gives expression4 ,it would be difficult to overrate the immense importance of this publication from the point of view of modern palaeobotany4 ,the art of making transparent sections of the tissues of fossil plants seems to have been first employed by ,sanderson1 a lapidary1 and it was afterwards considerably improved by ,nicol#bi4 ,this most important advance in methods of examination gave a new impetus to the subject1 but it is somewhat remarkable that the possibilities of the microscopical investigation of fossil plants have been but very imperfectly realised by botanical workers until quite recent years4 ,as regards such a flora as that of the ,coal-,measures1 we can endorse the opinion expressed at the beginning of the century in reference to the study of recent mosses--8,ohne das ,gttergeschenk des zusammengesetzten ,mikroskops ist auf diesem ,felde durchaus keine ,ernte#cj40 ,a useful summary of the history of the study of internal structure is given by ,knowlton in a memoir published in #ahhica4 ,not long after ,witham's book was issued there appeared a work of exceptional merit by ,corda#cb1 in which numerous ,palaeozoic plants are figured and fully described1 mainly from the standpoint of internal structure4 ,this author lays special stress on the importance of studying the microscopical structure of fossil plants4 ,sidenote3 ,,english ,,palaeobotanists4 ,without pausing to enumerate the contributions of such well-known continental authors as ,gppert1 ,cotta1 ,schimper1 ,stenzel1 ,schenk and a host of others1 we may glance for a moment at the services rendered by ,english investigators to the study of palaeobotanical histology4 ,unfortunately we cannot always extend our examination of fossil plants beyond the characters of external form and surface markings2 but in a few districts there are preserved remnants of ancient floras in which fragments of stems1 roots1 leaves and other structures have been petrified in such a manner as to retain with wonderful completeness the minute structure of their internal tissues4 ,during the deposition of the coal seams in parts of ,yorkshire and ,lancashire the conditions of fossilisation were exceptionally favourable1 and thus ,english investigators have been fortunately placed for conducting researches on the minute anatomy of the ,coal-,measure plants4 ,the late ,mr ,binney of ,manchester did excellent service by his work on the internal structure of some of the trees of the ,coal ,period forests4 ,in his introductory remarks to a monograph on the genus ,calamites1 after speaking of the desirability of describing our ,english specimens1 he goes on to say1 8,when this is done1 we are likely to possess a literature on our ,carboniferous fossils worthy of the first coal-producing country#cc40 ,the continuation and extension of ,binney's work in the hands of ,carruthers1 ,williamson1 and others1 whose botanical qualifications enabled them to produce work of greater scientific value1 has gone far towards the fulfilment of ,binney's prophecy4 ,sidenote3 ,,difficulties ,,of ,,identification4 ,in dealing with the structure of ,palaeozoic plants1 we shall be under constant obligation to the splendid series of memoirs from the pen of ,prof4 ,williamson#cd4 ,as the writer of a sympathetic obituary notice has well said3 8,in his fifty-fifth year he began the great series of memoirs which mark the culminating point of his scientific activity1 and which will assure to him1 for all time1 in conjunction with ,brongniart1 the honourable title of a founder of modern ,palaeobotany#ce40 ,if we look back through a few decades1 and peruse the pages of ,lindley and ,hutton's classic work#cf on the ,fossil flora of ,great ,britain1 a book which is indispensable to fossil botanists1 and read the description of such a genus as ,sigillaria or ,stigmaria2 or if we extend our retrospect to an earlier period and read ,woodward's description of an unusually good specimen of a ,lepidodendron1 and finally take stock of our present knowledge of such plants1 we realise what enormous progress has been made in palaeobotanical studies4 ,lindley and ,hutton1 in the preface to the first volume of the ,flora1 claim to have demonstrated that both ,sigillaria and ,stigmaria were plants with 8the highest degree of organization1 such as ,cactaeae1 or ,euphorbiaceae1 or even ,asclepiadeae02 ,woodward describes his ,lepidodendron 7,fig4 #a7 as 8an ironstone1 black and flat1 and wrought over one surface very finely1 with a strange cancellated work#cg40 ,thanks largely to the work of ,binney1 ,carruthers1 ,hooker1 ,williamson1 and to the labours of continental botanists1 we are at present almost as familiar with ,lepidodendron and several other ,coal-,measure genera as with the structure of a recent forest tree4 ,while emphasizing the value of the microscopic methods of investigation1 we are not disposed to take such a hopeless view of the possibilities of the determination of fossil forms1 in which no internal structure is preserved1 as some writers have expressed4 ,the preservation of minute structure is to be greatly desired from the point of view of the modern palaeobotanist1 but he must recognise the necessity of making such use as he can of the numberless examples of plants of all ages1 which occur only in the form of structureless casts or impressions4 ,illustration3 ,,fig4 #a4 ,four leaf-cushions of a ,lepidodendron4 ,drawn from a specimen in the ,woodward ,collection1 ,cambridge4 7,nat4 size47 ,in looking through the writings of the earlier authors we cannot help noticing their anxiety to match all fossil plants with living species2 but by degrees it was discovered that fossils are frequently the fragmentary samples of extinct types1 which can be studied only under very unfavourable conditions4 ,in the absence of those characters on which the student of living plants relies as guides to classification1 it is usually impossible to arrive at any trustworthy conclusions as to precise botanical affinity4 ,brongniart and other authors recognised this fact1 and instituted several convenient generic terms of a purely artificial and provisional nature1 which are still in general use4 ,the dangers and risks of error which necessarily attend our attempts to determine small and imperfect fragments of extinct species of plants1 will be briefly touched on in another place4 ,,chapter ,,ii4 ,,relation ,,of ,,palaeobotany ,,to ,,botany ,,and ,,geology4 8,la recherche du plan de la cration1 voil le but vers lequel nos efforts peuvent tendre aujourd'hui40 ,,gaudry1 #ahhc4 ,since the greater refinements and thoroughness of scientific methods and the enormous and ever-increasing mass of literature have inevitably led to extreme specialisation1 it is more than ever important to look beyond the immediate limits of one's own subject1 and to note its points of contact with other lines of research4 ,a palaeobotanist is primarily concerned with the determination and description of fossil plants1 but he must at the same time constantly keep in view the bearing of his work on wider questions of botanical or geological importance4 ,from the nature of the case1 we have in due measure to adapt the methods of work to the particular conditions before us4 ,it is impossible to follow in the case of all fossil species precisely the same treatment as with the more complete and perfect recent plants2 but it is of the utmost importance for a student of palaeobotany1 by adhering to the methods of recent botany1 to preserve as far as he is able the continuity of the past and present floras4 ,palaeontological work has often been undertaken by men who are pure geologists1 and whose knowledge of zoology or botany is of the most superficial character1 with the result that biologists have not been able to avail themselves1 to any considerable extent1 of the records of extinct forms of life4 ,they find the literature is often characterised by a special palaeontological phraseology1 and by particular methods of treatment1 which are unknown to the student of living plants and animals4 ,from this and other causes a purely artificial division has been made between the science of the organic world of to-day and that of the past4 ,sidenote3 ,,neglect ,,of ,,fossils ,,by ,,botanists4 ,fossils are naturally regarded by a stratigraphical geologist as records which enable him to determine the relative age of fossil-bearing rocks4 ,for such a purpose it is superfluous to inquire into the questions of biological interest which centre round the relics of ancient floras4 ,primarily concerned1 therefore1 with fixing the age of strata1 it is easy to understand how geologists have been content with a special kind of palaeontology which is out of touch with the methods of systematic zoology or botany4 ,on the other hand1 the botanist whose observations and researches have not extended beyond the limits of existing plants1 sees in the vast majority of fossil forms merely imperfect specimens1 which it is impossible to determine with any degree of scientific accuracy4 ,he prefers to wait for perfect material2 or in other words1 he decides that fossils must be regarded as outside the range of taxonomic botany4 ,it would seem1 then1 that the unsatisfactory treatment or comparative neglect of fossil plants1 has been in a large measure due to the narrowness of view which too often characterises palaeobotanical literature4 ,this has at once repelled those who have made a slight effort to recognise the subject1 and has resulted in a one-sided and1 from a biological standpoint1 unscientific treatment of this branch of science4 ,it must be admitted that palaeobotanists have frequently brought the subject into disrepute by their over-anxiety to institute specific names for fragments which it is quite impossible to identify4 ,this over-eagerness to determine imperfect specimens1 and the practice of drawing conclusions as to botanical affinity without any trustworthy evidence1 have naturally given rise to considerable scepticism as to the value of palaeobotanical records4 ,another point1 which will be dealt with at greater length in a later chapter1 is that geologists have usually shown a distinct prejudice against fossil plants as indices of geological age2 this again1 is no doubt to a large extent the result of imperfect and inaccurate methods of description1 and of the neglect of and consequent imperfect acquaintance with fossil plants as compared with fossil animals4 ,the student of fossil plants should endeavour to keep before him the fact that the chief object of his work is to deal with the available material in the most natural and scientific manner2 and by adopting the methods of modern botany1 he should always aim to follow such lines as may best preserve the continuity of past and present types of plants4 ,descriptions of floras of past ages and lists of fossil species1 should be so compiled that they may serve the same purpose to a stratigraphical geologist1 who is practically a geographer of former periods of the ,earth's history1 as the accounts of existing floras to students of present day physiography4 ,the effect of carrying out researches on some such lines as these1 should be to render available to both botanists and geologists the results of the specialist's work4 ,in some cases1 palaeobotanical investigations may be of the utmost service to botanical science1 and of little or no value to geology4 ,the discovery of a completely preserved gametophyte of ,lepidodendron or ,calamites1 or of a petrified ,moss plant in ,palaeozoic rocks would appeal to most botanists as a matter of primary importance1 but for the stratigraphical geologist such discoveries would possess but little value4 ,on the other hand the discovery of some characteristic species of ,coal-,measure plants from a deep boring through ,mesozoic or ,tertiary strata might be a matter of special geological importance1 but to the botanist it would be of no scientific value4 ,in very many instances1 however1 if the palaeobotanist follows such lines as have been briefly suggested1 the results of his labours should be at once useful and readily accessible to botanists and geologists4 ,as ,humboldt has said in speaking of ,palaeontology1 8the analytical study of primitive animal and vegetable life has taken a double direction2 the one is purely morphological1 and embraces especially the natural history and physiology of organisms1 filling up the chasms in the series of still living species by the fossil structures of the primitive world4 ,the second is more specially geognostic1 considering fossil remains in their relations to the superposition and relative age of the sedimentary formations#ch40 ,sidenote3 ,,fossil ,,plants ,,and ,,distribution4 ,to turn for a moment to some of the most obvious connections between palaeobotany and the wider sciences of botany and geology4 ,the records of fossil species must occupy a prominent position in the data by which we may hope to solve some at least of the problems of plant evolution4 ,from the point of view of distribution1 palaeobotany is of considerable value1 not only to the student of geographical botany1 but to the geologist1 who endeavours to map out the positions of ancient continents with the help of palaeontological evidence4 ,the present distribution of plants and animals represents but one chapter in the history of life on the ,earth2 and to understand or appreciate the facts which it records1 we have to look back through such pages as have been deciphered in the earlier chapters of the volume4 ,the distribution of fossil plants lies at the foundation of the principles of the present grouping of floras on the ,earth's surface4 ,those who have confined their study of distribution to the plant geography of the present age1 must supplement their investigations by reference to the work of palaeobotanical writers4 ,if the lists of plant species drawn up by specialists in fossil botany1 have been prepared with a due sense of the important conclusions which botanists may draw from them from the standpoint of distribution1 they will be readily accepted as sound links in the chain of evidence4 ,unfortunately1 however1 if many of the lists of ancient floras were made use of in such investigations1 the conclusions arrived at would frequently be of little value on account of the untrustworthy determinations of many of the species4 ,in the case of particular genera the study of the distribution of the former species both in time and space1 that is geologically and geographically1 points to rational explanations of1 or gives added significance to1 the facts of present day distribution4 ,that isolated conifer1 ,ginkgo biloba ,l4 now restricted to ,japan and ,china1 was in former times abundant in ,europe and in other parts of the world4 ,it is clearly an exceedingly ancient type1 isolated not only in geographical distribution but in botanical affinities1 which has reached the last stage in its natural life4 ,the ,mammoth trees of ,california 7,sequoia sempervirens ,endl41 and ,s4 gigantea ,lindl4 and ,gord47 afford other examples of a parallel case4 ,the ,tulip tree of ,north ,america and ,china and other allied forms are fairly common in the ,tertiary plant beds of ,europe1 but the living representatives are now exclusively ,north ,american4 ,such differences in distribution as are illustrated by these dicotyledonous forest trees in ,tertiary times and at the present day1 have been clearly explained with the help of the geological record4 ,forbes1 ,darwin1 ,asa ,gray#ci and others have been able to explain many apparent anomalies in the distribution of existing plants1 and to reconcile the differences between the past and present distribution of many genera by taking account of the effect on plant life of the glacial period4 ,as the ice gradually crept down from the polar regions and spread over the northern parts of ,europe1 many plants were driven further south in search of the necessary warmth4 ,in the ,american continent such migration was rendered possible by the southern land extension2 in ,europe on the other hand the southerly retreat was cut off by impassable barriers1 and the extinction of several genera was the natural result4 ,the comparatively abundant information which we possess as to the past vegetation of polar regions and the value of such knowledge to geologists and botanists alike is in striking contrast to the absence of similar data as regards ,antarctic fossils4 ,darwin in an exceedingly interesting letter to ,hooker propos of a forthcoming ,british ,association address1 referring to this subject writes as follows3-- 8,the extreme importance of the ,arctic fossil plants is self-evident4 ,take the opportunity of groaning over our ignorance of the ,lignite plants of ,kerguelen ,land1 or any ,antarctic land4 ,it might do good#dj40 ,in working out any collection of fossil plants1 it would be well1 therefore1 to bear in mind that our aim should be rather to reproduce an accurate fragment of botanical history1 than to perform feats of determination with hopelessly inadequate specimens4 ,had this principle been generally followed1 the number of fossil plant species would be enormously reduced1 but the value of the records would be considerably raised4 ,sidenote3 ,,fossil ,,plants ,,and ,,climate4 ,our knowledge of plant anatomy1 and of those laws of growth which govern certain classes of plants to-day and in past time1 has been very materially widened and extended by the facts revealed to us by the detailed study of ,coal-,measure species4 ,the modern science of ,plant ,biology1 refounded by ,charles ,darwin1 has thrown considerable light on the laws of plant life1 and it enables us to correlate structural characteristics with physiological conditions of growth4 ,applying the knowledge gained from living plants to the study of such extinct types as permit of close microscopic examination1 we may obtain a glimpse into the secrets of the botanical binomics of ,palaeozoic times4 ,the wider questions of climatic conditions depend very largely upon the evidence of fossil botany for a rational solution4 ,as an instance of the best authenticated and most striking alternation in climatic conditions in comparatively recent times1 we may cite the glacial period or ,ice-,age4 ,the existence of ,arctic conditions has been proved by purely geological evidence1 but it receives additional confirmation1 and derives a wider importance from the testimony of fossil plants4 ,in rocks deposited before the spread of ice from high northern latitudes1 we find indubitable proofs of a widely distributed subtropical flora in ,central and ,northern ,europe4 ,passing from these rocks to more recent beds there are found indications of a fall in temperature1 and such northern plants as the dwarf ,birch1 the ,arctic ,willow and others reveal the southern extension of ,arctic cold to our own latitudes4 ,the distribution of plants in time1 that is the range of classes1 families1 genera and species of plants through the series of strata which make up the crust of the earth1 is a matter of primary importance from a botanical as well as from a geological point of view4 ,among the earlier writers1 ,brongniart recognised the marked differences between the earlier and later floras1 and attempted to correlate the periods of maximum development of certain classes of plants with definite epochs of geological history4 ,he gives the following classification in which are represented the general outlines of plant development from ,palaeozoic to ,tertiary times#da4 ,i4 ,reign of ,acrogens #a4 ,carboniferous epoch4 #b4 ,permian epoch4 ,,ii4 ,reign of ,gymnosperms #c4 ,triassic epoch4 #d4 ,jurassic epoch 7including the ,wealden74 ,,iii4 ,reign of ,angiosperms #e4 ,cretaceous epoch4 #f4 ,tertiary epoch4 ,since ,brongniart's time this method of classification has been extended to many of the smaller subdivisions of the geological epochs1 and species of fossil plants are often of the greatest value in questions of correlation4 ,in recent years the systematic treatment of ,coal-,measure and other plants in the hands of various ,continental and ,english writers has clearly demonstrated their capabilities for the purpose of subdividing a series of strata into stages and zones#db4 ,the more complete becomes our knowledge of any flora1 the greater possibility there is of making use of the plants as indices of geological age#dc4 ,sidenote3 ,,fossil ,,plants ,,and ,,phylogeny4 ,not only is it possible to derive valuable aid in the correlation of strata from the facts of plant distribution1 but we may often follow the various stages in the history of a particular genus as we trace the records of its occurrence through the geologic series4 ,in studying the march of plant life through past ages1 the botanist may sometimes follow the progress of a genus from its first appearance1 through the time of maximum development1 to its decline or extinction4 ,in the ,palaeozoic forests there was perhaps no more conspicuous or common tree than the genus long known under the name of ,calamites4 ,this plant attained a height of fifty or a hundred feet1 with a proportionate girth1 and increased in thickness in a manner precisely similar to that in which our forest trees grow in diameter4 ,the exceptionally favourable conditions under which specimens of calamitean plants have been preserved1 have enabled us to become almost as familiar with the minute structure of their stems and roots1 as well as with their spore-producing organs1 as with those of a living species4 ,in short1 it is thoroughly established that ,calamites agrees in most essential respects with our well known ,equisetum1 and must be included in the same order1 or at least sub-class1 as the recent genus of ,equisetaceae4 ,as we ascend the geologic series from the ,coal-,measures1 a marked numerical decline of ,calamites is obvious in the ,permian period1 and in the red sandstones of the ,vosges1 which belong to the same series of rocks as the ,triassic strata of the ,cheshire plain1 the true ,calamites is replaced by a large ,equisetum apparently identical in external appearance and habit of growth with the species living to-day4 ,in the more recent strata the ,horse-tails are still represented1 but the size of the ,tertiary species agrees more closely with the comparatively small forms which have such a wide geographical distribution at the present time4 ,thus we are able to trace out the history of a recent genus of ,vascular ,cryptogams1 and to follow a particular type of organisation from the time of its maximum development1 through its gradual transition to those structural characters which are represented in the living descendants of the arborescent ,calamites of the coal-period forests4 ,the pages of such a history are frequently imperfect and occasionally missing1 but others1 again1 are written in characters as clear as those which we decipher by a microscopical examination of the tissues of a recent plant4 ,as one of the most striking instances in which the microscopic study of fossil plants has shown the way to a satisfactory solution of the problems of development1 we may mention such extinct genera as ,lyginodendron1 ,myeloxylon and others4 ,each of these genera will be dealt with at some length in the systematic part of the book1 and we shall afterwards discuss the importance of such types1 from the point of view of plant evolution4 ,the botanist who would trace out the phylogeny of any existing class or family1 makes it his chief aim to discover points of contact between the particular type of structure which he is investigating1 and that of other more or less closely related classes or families4 ,confining himself to recent forms1 he may discover1 here and there1 certain anatomical or embryological facts1 which suggest promising lines of inquiry in the quest after such affinities as point to a common descent4 ,without recourse to the evidence afforded by the plants of past ages1 we must always admit that our existing classification of the vegetable kingdom is an expression of real gaps which separate the several classes of plants from one another4 ,on the other hand our recently acquired and more accurate knowledge of such genera as have been alluded to1 has made us acquainted with types of plant structure which enable us to fill in some of the lacunae in our existing classification4 ,in certain instances we find merged in a single species morphological characteristics which1 in the case of recent plants1 are regarded as distinctive features of different subdivisions4 ,it has been clearly demonstrated that in ,lyginodendron1 we have anatomical peculiarities typical of recent cycads1 combined with structural characteristics always associated with existing ferns4 ,in rare cases1 it happens that the remarkably perfect fossilisation of the tissues of fossil plants1 enables us not only to give a complete description of the histology of extinct forms1 but also to speak with confidence as to some of those physiological processes which governed their life4 ,sidenote3 ,,geological ,,history4 ,so far1 palaeobotany has been considered in its bearings on the study of recent plants4 ,from a geological point of view the records of ancient floras have scarcely less importance4 ,in recent years1 facts have been brought to light1 which show that plants have played a more conspicuous part than has usually been supposed as agents of rock-building4 ,as tests of geologic age1 there are good grounds for believing that the inferiority of plants to animals is more apparent than real4 ,this question1 however1 must be discussed at greater length in a later chapter4 ,enough has been said to show the many-sided nature of the science of ,fossil ,plants1 and the wide range of the problems which the geologist or botanist may reasonably expect to solve1 by means of trustworthy data afforded by scientific palaeobotanical methods4 ,,chapter ,,iii4 ,,geological ,,history4 8,but how can we question dumb rocks whose speech is not clear#dd80 ,in attempting to sketch in briefest outline the geological history of the ,earth1 the most important object to keep in view is that of reproducing as far as possible the broad features of the successive stages in the building of the ,earth's crust4 ,it is obviously impossible to go into any details of description1 or to closely follow the evolution of the present continents2 at most1 we can only refer to such facts as may serve as an introduction of the elements of stratigraphical geology to non-geological readers4 ,for a fuller treatment of the subject reference must be made to special treatises on geology4 ,for the sake of convenience1 it is customary in stratigraphical geology as also in biology1 to make use of our imperfect knowledge as an aid to classification4 ,if we possessed complete records of the ,earth's history1 we should have an unbroken sequence1 not merely of the various forms of life that ever existed1 but of the different kinds of rocks formed in the successive ages of past time4 ,as gaps exist in the chain of life1 so also do we find considerable breaks in the sequence of strata which have been formed since the beginning of geologic time4 ,the danger as well as the convenience of artificial classification must be kept in view4 ,this has been well expressed by ,freeman1 in speaking of architectural styles1--8,our minds10 he says1 8are more used to definite periods2 they neglect or forget transitions which do indeed exist#de40 ,the idea of definite classification is liable to narrow our view of uniformity and the natural sequence of events4 ,sidenote3 ,,rock-,,building4 ,composing that part of the earth which is accessible to us1--or as it is generally called the earth's crust1--there are rocks of various kinds1 of which some have been formed by igneous agency1 either as lavas or beds of ashes1 or in the form of molten magmas which gradually cooled and became crystalline below a mass of superincumbent strata4 ,with these rocks we need not concern ourselves4 ,a large portion of the earth's crust consists of such materials as sandstones1 limestones1 shales1 and similar strata which have been formed in precisely the same manner as deposits are being accumulated at the present day4 ,the whole surface of the earth is continually exposed to the action of destructive agencies1 and suffers perpetual decay2 it is the products of this ceaseless wear and tear that form the building materials of new deposits4 ,the operation of water in its various forms1 of wind1 changes of temperature1 and other agents of destruction cannot be fully dealt with in this short summary4 ,a river flowing to the sea or emptying itself into an inland lake1 carries its burden of gravel1 sand1 and mud1 and sooner or later1 as the rate of flow slackens1 it deposits the materials in the river-bed or on the floor of the sea or lake4 ,fragments of rock1 chipped off by wedges of ice1 or detached in other ways from the parent mass1 find their way to the mountain streams1 and if not too heavy are conveyed to the main river1 where the larger pieces come to rest as more or less rounded pebbles4 ,such water-worn rocks accumulate in the quieter reaches of a swiftly flowing river1 or are thrown down at the head of the river's delta4 ,if such a deposit of loose water-worn material became cemented together either by the consolidating action of some solution percolating through the general mass1 or by the pressure of overlying deposits1 there would be formed a hard rock made up of rounded fragments of various kinds of strata derived from different sources4 ,such a rock is known as a ,,conglomerate4 ,the same kind of rock may be formed equally well by the action of the sea2 an old sea-beach with the pebbles embedded in a cementing matrix affords a typical example of a coarse conglomerate4 ,plant remains are occasionally met with in conglomerates1 but usually in a fragmentary condition4 ,from a conglomerate composed of large water-worn pebbles1 to a fine homogeneous sandstone there are numerous intermediate stages4 ,a body of water1 with a velocity too small to carry along pebbles of rock in suspension or to roll them along the bed of the channel1 is still able to transport the finer fragments or grains of sand1 but as a further decrease in the velocity occurs1 these are eventually deposited as beds of coarse or fine sand4 ,the stretches of sand on a gradually shelving sea shore1 or the deposits of the same material in a river's delta1 have been formed by the gradual wearing away and disintegration of various rocks1 the detritus of which has been spread out in more or less regular beds on the floor of a lake or sea4 ,such accumulations of fine detrital material1 if compacted or cemented together1 become typical ,,sandstones4 ,in tracing beds of sandstone across a tract of country1 it is frequently found that the character of the strata gradually alters2 mud or clay becomes associated with the sandy deposit1 until finally the sandstone is replaced by beds of dark coloured shale4 ,similarly the sandy detritus on the ocean floor1 or in an inland lake1 when followed further and further from the source from which the materials were derived1 passes by degrees into argillaceous sand1 and finally into sheets of dark clay or mud4 ,the hardened beds of clay or fine grained mud become transformed into ,,shales4 ,as a general rule1 then1 shales are rocks which have been laid down in places further from the land1 or at a greater distance from the source of origin of the detrital material1 than sandstones or conglomerates4 ,the conglomerates1 or old shingle beaches1 usually occur in somewhat irregular patches1 marking old shore-lines or the head of a river delta4 ,coarse sandstones1 or grits1 may occur in the form of regularly bedded strata stretching over a wide area2 and shales or clays may be followed through a considerable extent of country4 ,the finer material composing the clays and shales has been held longer in suspension and deposited in deeper water in widespread and fairly horizontal layers4 ,in some districts sandstones occur in which the individual grains show a well marked rounding of the angles1 and in which fossils are extremely rare or entirely absent4 ,the close resemblance of such deposits to modern desert sands suggests a similar method of formation2 and there can be no doubt that in some instances there have been preserved the wind-worn desert sands of former ages4 ,aeolian or wind-formed accumulations1 although by no means common1 are of sufficient importance to be mentioned as illustrating a certain type of rock4 ,sidenote3 ,,calcareous ,,rocks4 ,the thick masses of limestone which form so prominent a feature in parts of ,england and ,ireland1 have been formed in a manner different from that to which sandstones and shales owe their origin4 ,on the floor of a clear sea1 too far from land to receive any water-borne sediment1 there is usually in process of formation a mass of calcareous material1 which in a later age may rise above the surface of the water as chalk or ,,limestone4 ,those organisms living in the sea1 which are enclosed either wholly or in part by calcareous shells1 are agents of limestone-building2 their shells constantly accumulating on the floor of the sea give rise in course of time to a thick mass of sediment1 composed in great part of carbonate of lime4 ,some of the shells in such a deposit may retain their original form1 the calcareous body may on the other hand be broken up into minute fragments which are still recognisable with the help of a microscope1 or the shells and other hard parts may be dissolved or disintegrated beyond recognition1 leaving nothing in the calcareous sediment to indicate its method of formation4 ,not a few limestones consist in part of fossil corals1 and owe their origin to colonies of coral polyps which built up reefs or banks of coral in the ancient seas4 ,in the white cliffs of ,dover1 ,flamborough ,head and other places1 we have a somewhat different form of calcareous rock1 which in part consists of millions of minute shells of ,foraminifera1 in part of broken fragments of larger shells of extinct molluscs1 and to some extent of the remains of siliceous sponges4 ,as a general rule1 limestones and chalk rocks are ancient sediments1 formed in clear and comparatively deep water1 composed in the main of carbonate of lime1 in some cases with a certain amount of carbonate of magnesium1 and occasionally with a considerable admixture of silica4 ,in such rocks land-plants must necessarily be rare4 ,there are1 however1 limestones which wholly or in part owe their formation to masses of calcareous algae1 which grew in the form of submarine banks or on coral reefs4 ,occasionally the remains of these algae are clearly preserved1 but frequently all signs of plant structure have been completely obliterated4 ,again1 there occur limestone rocks formed by chemical means1 and in a manner similar to that in which beds of travertine are now being accumulated4 ,granites1 basalts1 volcanic lavas1 tuffs1 and other igneous rocks need not claim our attention1 except in such cases as permit of plant remains being found in association with these materials4 ,showers of ashes blown from a volcano1 may fall on the surface of a lake or sea and become mixed with sand and mud of subaerial origin4 ,streams of lava occasionally flow into water1 or they may be poured from submarine vents1 and so spread out on the ocean bed with strata of sand or clay4 ,passing from the nature and mode of origin of the sedimentary strata to the manner of their arrangement in the ,earth's crust1 we must endeavour to sketch in the merest outline the methods of stratigraphical geology4 ,the surface of the ,earth in some places stands out in the form of bare masses of rock1 roughly hewn or finely carved by ,nature's tools of frost1 rain or running water2 in other places we have gently undulating ground with beds of rock exposed to view here and there1 but for the most part covered with loose material such as gravel1 sands1 boulder clay and surface soil4 ,sidenote3 ,,geological ,,sections4 ,in the flat lands of the fen districts1 the peat beds and low-lying salt marshes form the surface features1 and are the connecting links between the rock-building now in progress and the deposits of an earlier age4 ,if we could remove all these surface accumulations of sand1 gravel1 peat and surface soil1 and take a bird's eye view of the bare surface of the rocky skeleton of the earth's crust1 we should have spread before us the outlines of a geological map4 ,in some places fairly horizontal beds of rock stretching over a wide extent of country1 in another the upturned edges of almost vertical strata form the surface features2 or1 again1 irregular bosses of crystalline igneous rock occur here and there as patches in the midst of bedded sedimentary or volcanic strata4 ,a map showing the boundaries and distribution of the rocks as seen at the surface1 tells us comparatively little as to the relative positions of the different rocks below ground1 or of the relative ages of the several strata4 ,if we supplement this superficial view by an inspection of the position of the strata as shown on the walls of a deep trench cut across the country1 we at once gain very important information as to the relative position of the beds below the earth's surface4 ,the face of a quarry1 the side of a river bed or a railway cutting1 afford ,,horizontal ,,sections or ,,profiles which show whether certain strata lie above or below others1 whether a series of rocks consists of parallel and regularly stratified beds1 or whether the succession of the strata is interfered with by a greater or less divergence from a parallel arrangement4 ,if1 for example1 a section shows comparatively horizontal strata lying across the worn down edges of a series of vertical sedimentary rocks1 we may fairly assume that some such changes as the following have taken place in that particular area4 ,the underlying beds were originally laid down as more or less horizontal deposits2 these were gradually hardened and compacted1 then elevated above sea-level by a folding of the earth's crust2 the crests of the folds were afterwards worn down by denudation1 and the eroded surface finally subsided below sea-level and formed the floor on which newer deposits were built up4 ,such breaks in the continuity of stratified deposits are known as ,,unconformities2 in the interval of time which they represent great changes took place of which the records are either entirely lost1 or have to be sought elsewhere4 ,in certain more exceptional cases1 it is possible to obtain what is technically known as a ,,vertical ,,section2 for example if a deep boring is sunk through a series of rocks1 and the core of the boring examined1 we have as it were a sample of the earth's crust which may often teach us valuable lessons which cannot be learnt from maps or horizontal sections4 ,sidenote3 ,,inversion ,,of ,,strata4 ,it is obvious1 that in a given series of beds1 which are either horizontal or more or less obliquely inclined1 the underlying strata were the first formed1 and the upper beds were laid down afterwards4 ,if1 however1 we trusted solely to the order of superposition in estimating relative age1 our conclusions would sometimes be very far from the truth4 ,recent geological investigations have brought to light facts well nigh incredible as to the magnitude and extent of rock-foldings4 ,in regions of great earth-movements1 the crust has been broken along certain lines1 and great masses of strata have been thrust for miles along the tops of newer rocks4 ,thus it may be brought about that the natural sequence of a set of beds has been entirely altered1 and older rocks have come to overlie sediments of a later geological age4 ,facts such as these clearly illustrate the difficulties of correct geological interpretation4 ,in the horizontal section 7,fig4 #b71 from the summit of ,bzistock on the left to ,saasterg on the right1 we have a striking case of intense rock-folding and dislocation#df4 ,prof4 ,heim#dg of ,geneva has given numerous illustrations of the almost incredible positions assumed in the ,swiss ,mountains by vast thicknesses of rocks1 and in the accompanying section taken from a recent work by ,rothpletz we have a compact example of the possibilities of earth-movements as an agent of rock-folding4 ,the section illustrates very clearly an exception to the rule that the order of superposition of a set of beds indicates the relative age of the strata4 ,the horizontal line at the base is drawn at a height of #afej metres above sea-level1 and the summit of ,bzistock reaches a height of #bcdj m4 ,the youngest rocks seen in the diagram are the ,eocene beds e1 at the base and as small isolated patches on the right-hand end of the section2 the main mass of material composing the higher ground has been bodily thrust over the ,eocene rocks1 and in this process some of the beds1 b and c1 have been folded repeatedly on themselves4 ,similar instances of the overthrusting of a considerable thickness of strata have been described in the ,north-west ,highlands of ,scotland#dh and elsewhere in the ,british ,isles4 ,it is important therefore to draw attention to cases of extreme folding1 as such phenomena are by no means exceptional in many parts of the world4 ,illustration3 ,,fig4 #b4 ,section from ,bzistock to ,saasterg4 ,after ,rothpletz1 7#id7 ,pl4 ,,ii4 fig4 #b4 a ,sernifit or ,verrucano 7,permian74 b ,rthidolomit etc4 7,permian74 c ,dogger 7,jurassic74 d ,malm 7,jurassic74 e ,eocene4 ,the order of superposition of strata has afforded the key to our knowledge of the succession of life in geologic time1 and the refinements of the stratigraphical correlation of sedimentary rocks are based on the comparison of their fossil contents4 ,by a careful examination of the relics of fossil organisms obtained from rocks of all ages and countries1 it has been found possible to restore in broken outline the past history of the ,earth4 ,by means1 then1 of stratigraphical and palaeontological evidence1 a classification of the various rocks has been established1 the lines of division being drawn in such places as represent gaps in the fossil records1 or striking and widespread unconformities between different series of deposits4 ,it is only in a few regions that we find rocks which can reasonably be regarded as the foundation stones of the ,earth4 ,as the globe gradually cooled1 and its molten mass became skinned over with a solid crust1 crystalline rocks must have been produced before the dawn of life1 and before water could remain in a liquid form on the rocky surface4 ,as soon as the temperature became sufficiently low1 running water and rain began the work of denudation and rock disintegration which has been ceaselessly carried on ever since4 ,in this continual breaking down and building up of the ,earth's surface1 it would be no wonder if but few remnants were left of the first formed sediments of the earliest age4 ,the action of heat1 pressure and chemical change accompanying rock-foldings and crust-wrinklings1 often so far alters sedimentary deposits1 that their original form is entirely lost1 and sandstone1 shales and limestones become metamorphosed into crystalline quartzites1 slates and marbles4 ,the operation of metamorphism is therefore another serious difficulty in the way of recognising the oldest rocks4 ,the earliest animals and plants which have been discovered are not such as we should expect to find as examples of the first products of organic life4 ,below the oldest known fossiliferous rocks1 there must have been thousands of feet of sedimentary material1 which has either been altered beyond recognition1 or from some cause or other does not form part of our present geological record4 ,as a general introduction to geological chronology1 a short summary may be given of the different formations or groups of strata1 to which certain names have been assigned to serve as convenient designations for succeeding epochs in the world's evolution4 ,the following table 7,fig4 #c1 pp4 #cb1 #cc7 represents the geological series in a convenient form2 the most characteristic rocks of each period are indicated by the usual conventional shading1 and the most important breaks or lacunae in the records are shown by gaps and uneven lines4 ,the relative thickness of the rocks of each period is approximately shown2 but the vertical extent of the oldest or ,archaean rocks as shown in ,fig4 #c represents what is without doubt but a fraction of their proportional thickness4 ,this table is taken1 with certain alterations1 from a paper by ,prof4 ,t4 ,mc,kenny ,hughes in the ,cambridge ,philosophical ,proceedings for #ahgi4 ,speaking of the graphic method of showing the geological series1 the author of the paper says1 8,it is convenient to have a table of the known strata1 and although we cannot arrange all the rocks of the world in parallel columns1 and say that ,,abc of one area are exactly synchronous with ,a,b,c of another1 still if we take any one country and establish a grouping for it1 we find so many horizons at which equivalent formations can be identified in distant places1 that we generally make an approximation to ,,homotaxis as ,huxley called it4 ,the most convenient grouping is obviously to bracket together locally continuous deposits1 i4e4 all the sediment which was formed from the time when the land went down and accumulation began1 to the time when the sea bottom was raised and the work of destruction began4 ,in the accompanying table ,i have given the rocks of ,great ,britain classified on this system1 and bearing in mind that waste in one place must be represented by deposit elsewhere1 ,i have represented the periods of degradation by intervals estimated where possible by the amount of denudation known to have taken place between the periods of deposition in the same district#di40 ,illustration3 ,,table ,,of ,,strata4 ,,recent ,,glacial ,,quaternary ,,pliocene ,,miocene ,,oligocene ,,tertiary ,,eocene ,,cretaceous ,,jurassic ,,mesozoic ,,trias ,,permian ,coal-,measures ,millstone ,grit ,,carboniferous ,yoredale ,rocks ,mountain ,limestone ,devonian ,upper ,old ,red ,,devonian ,sandstone ,lower ,old ,red ,sandstone ,ludlow ,,silurian ,wenlock ,,palaeozoic ,may ,hill ,upper ,bala ,lower ,bala ,,ordovician ,llandeilo ,arenig ,tremadoc ,lingula ,flags ,,cambrian ,menevian ,harlech ,,lavas1 ,,volcanic ,,ashes1 ,,granitoid ,,archaean ,,rocks ,,and ,,schists ,,of ,,enormous ,,thickness ,fig #c4 ,i4 ,archaean4 8,men can do nothing without the make-believe of a beginning40 ,,george ,,eliot4 ,there is perhaps no problem at once so difficult and so full of interest to the student of the ,earth's history1 as the interpretation of the fragmentary records of the opening stages in geological and organic evolution4 ,in tracing the growth and development of the human race1 it becomes increasingly difficult to discover and decipher written documents as we penetrate farther back towards the beginning of the historical period2 the records are usually incomplete and fragmentary1 or rendered illegible by the superposed writings of a later date4 ,so in the records of the rocks1 as we pass beyond the oldest strata in which clearly preserved fossils are met with1 we come to older rocks which afford either no data as to the period in which they were formed1 or like the palimpsest1 with its original characters almost obliterated by a late ,,ms41 the older portions of the ,earth's crust have been used and re-used in the rock-building of later ages4 ,in the first place1 it is exceedingly difficult to determine with any certainty what rocks may be regarded as trustworthy fragments of a primaeval land4 ,throughout the geological eras the ,earth's surface has been subjected to foldings and wrinklings1 volcanic activity has been almost unceasing1 and there is abundant evidence to show how the original characters of both igneous and sedimentary rocks may be entirely effaced by the operation of chemical and physical forces4 ,it was formerly held that coarsely crystalline rocks such as granite are the oldest portions of the crust1 but modern geology has conclusively proved that many of the so-called fundamental masses of rock are merely piles of ancient sediments which have been subjected to the repeated operation of powerful physical and chemical forces1 and have undergone a complete rearrangement of their substance4 ,as the result of more detailed investigations1 many regions formerly supposed to consist of the foundation stones of the ,earth's crust1 are now known to have been centres of volcanic disturbance and widespread metamorphism1 and to be made up of post-archaean rocks4 ,sidenote3 ,,the ,,oldest ,,rocks4 ,the first formed rocks no doubt became at once the prey of denudation and disintegration1 and on their surface would be accumulated the products of their own destruction3 newer strata would entirely cover up portions of the original land1 to be in their turn succeeded by still later deposits4 ,there is reason to believe that in the remotest ages of the ,earth's history1 the forces of denudation and igneous activity were more potent than in later times1 and thus the oldest rocks could hardly retain their original structure through the long ages of geologic time4 ,the earliest representatives of organic life were doubtless of such a perishable nature that their remains could not be preserved in a fossil state even under the most favourable conditions4 ,such organisms1 whether plants or animals1 as possessed any resistant tissues or hard skeletons might be preserved in the oldest rocks1 but as these strata became involved in earth-foldings or were penetrated by injections of igneous eruptions1 the relics of life would be entirely destroyed4 ,it is1 in short1 practically hopeless to look for any fragments of the primitive crust except such as have undergone very considerable metamorphism1 and equally futile to search for any recognisable remains of primitive life4 ,in many parts of the world vast thicknesses of rock occur below the oldest known fossiliferous strata2 these consist largely of laminated crystalline masses composed of quartz1 felspar1 and other minerals1 having in fact the same composition as granite1 but differing in the regular arrangement of the constituent parts4 ,to such rocks the terms gneiss and schist have been applied4 ,rocks of this kind are by no means always of ,archaean age1 but many of the earliest known rocks consist of gneisses of various kinds1 associated with altered lavas1 metamorphosed ashes1 breccias and other products of volcanic activity2 with these there may be limestones1 shales1 sandstones1 and other strata more or less closely resembling sedimentary deposits4 ,such a succession of gneissic rocks has been described as occupying a wide area in the basin of the ,st ,lawrence river1 and to these enormously thick and widespread masses a late ,director of the ,canadian ,geological ,survey applied the term ,laurentian4 ,these ,laurentian rocks1 with similar strata in ,scandinavia1 the north-west ,highlands of ,scotland1 in certain parts of such mountain ranges as the ,alps1 ,pyrenees1 ,carpathians1 ,himalayas1 ,andes1 ,atlas1 c41 have been classed together as members of the oldest geological period1 and are usually referred to under the name of ,archaean1 or less frequently ,azoic rocks4 ,in some of the uppermost ,archaean rocks there have been recently discovered a few undoubted traces of fossil animals1 but with this exception no fossils are known throughout the great mass of ,archaean strata4 ,it is true that some authorities regard the beds of graphite and other rocks as a proof of the abundance of plant life1 but this supposition is not supported by any convincing evidence4 ,the term ,azoic#ej applied by some writers to these oldest rocks suggests the absence of life during the period in which they were formed4 ,life there must have been1 though we are unable to discover its records4 ,the period of time represented by the ,archaean or ,pre-,cambrian rocks must be enormous1 and it was in that earliest era that the first links in the chain of life were forged4 ,,ii4 ,cambrian4 ,the term ,cambrian was adopted by ,sedgwick for a series of sedimentary rocks in ,north ,wales 7,cambria74 ,in that district1 in ,south ,wales1 the ,longmynd ,hills1 the ,malverns1 in ,scotland1 and other regions there occur more or less highly folded and contorted beds of pebbly conglomerate1 sandstones1 shales and slates resting on the uneven surface of an ,archaean foundation4 ,it is in these ,cambrian rocks that trustworthy records of organic life are first met with4 ,among the most constant and characteristic fossils of this period are the extinct and aberrant members of the crustacea1 the trilobites2 these with some brachiopods1 sponges1 and other fossils comprise the oldest fauna1 of which the ancestral types have yet to be discovered4 ,during the last few decades the number of ,cambrian fossils has been considerably increased1 and in certain regions of ,north ,america and ,china there are found many thousand feet of strata above the typical ,archaean rocks and below the newer fossiliferous beds of ,cambrian age4 ,it is reasonable to suppose that future research may extend the present limits of fossil-bearing rocks below the horizon1 which is marked by the occurrence of the widely distributed and oldest known trilobite1 the genus ,olenellus4 ,the vast thickness of ,cambrian strata was for the most part laid down on the floor of a comparatively deep sea2 other members of the series represent the shingle beaches and coast deposits accumulated on the slopes of ,archaean islands4 ,there have been many conjectures as to the distribution of land and sea during the deposition of these rocks2 but the data are too imperfect to enable us to restore with any degree of confidence the physical geography of this ,palaeozoic epoch1 of which the sediments stood out as islands of ,cambrian land during many succeeding ages4 ,,iii4 ,ordovician4 ,since the days when ,sedgwick and ,murchison first worked out the succession of ,palaeozoic strata in ,north ,wales1 there has always existed a considerable difference of opinion as to the best method of subdividing the ,cambrian-,silurian strata4 ,later research has shown that the rocks included by ,sedgwick in his ,cambrian system1 fall naturally into two groups2 for the upper of these ,prof4 ,lapworth has suggested the term ,ordovician1 from the name of the ,ordovices1 who inhabited a part of northern ,wales4 ,at the base of the system we have a series of volcanic and sedimentary rocks to which ,sedgwick gave the name ,arenig2 above these there occur the ,llandeilo ,flags1 succeeded by a considerable thickness of rocks known as the ,bala series4 ,the rocks making up these ,ordovician sediments consist for the most part of slates1 sandstones and limestones with volcanic ashes and lavas4 ,much of the typical ,welsh scenery owes its character to the folded and weathered rocks laid down on the floor of the ,ordovician sea1 on which from many centres of volcanic activity lava streams and showers of ash were spread out between sheets of marine sediment4 ,the ,arenig ,hills1 ,snowdonia1 and many other parts of ,north and ,south ,wales1 parts of ,shropshire1 ,scotland1 ,sweden1 ,russia1 ,bohemia1 ,north ,america and other regions consist of great thicknesses of ,ordovician strata4 ,,iv4 ,silurian4 ,passing up a stage higher in the geologic series1 we have a succession of conglomerates1 sandstones1 shales1 and limestones2 in other words1 a series of beds which represent pebbly shore deposits1 the sands and muds of deeper water1 and the accumulated dbris of calcareous skeletons of animals which lived in the clear water of the ,silurian sea4 ,the term ,silurian 7,siluria was the country of ,caractacus and the old ,britons known as ,silures#ea7 was first applied by ,murchison in #ahce to a more comprehensive series of rocks than are now included in the ,silurian system4 ,the rocks of this period occur in ,wales1 ,shropshire1 parts of ,scotland1 ,ireland1 ,scandinavia1 ,russia1 the ,united ,states and other countries4 ,after the accumulation of the thick ,ordovician sediments1 the sea-floor was upraised and in places converted into ridges or islands of land1 of which the detritus formed part of the material of ,silurian deposits4 ,the limestones of the ,wenlock ridge have yielded an abundant fauna1 consisting of corals1 crinoids1 molluscs and other invertebrates4 ,in this period we have the first representatives of the ,vertebrata1 discovered in the rocks of ,ludlow4 ,in fact1 in the ,silurian period1 8all the great divisions of the ,animal ,kingdom were already represented#eb40 ,v4 ,devonian4 ,by the continued elevation of the ,silurian sea-floor1 large portions became dry land1 and during the succeeding period most of the ,british area formed part of a continental mass4 ,over the southern part of ,england1 there still lay an arm of the sea1 and in this were laid down the marine sediments which now form part of ,devon1 and from which the name ,devonian has been taken as a convenient designation for the strata of this period4 ,in parts of the northern land1 in the region now occupied by ,scotland1 there were large inland lakes1 on the floor of which vast thicknesses of shingle beds and coarse sands 78,old ,red ,sandstone07 were slowly accumulated2 and it has been shown by ,sir ,archibald ,geikie and others that during this epoch there were considerable outpourings of volcanic material in the ,scotch area4 ,farther to the ,west and ,south-west there was another large lake in which the so-called ,kiltorkan beds of ,ireland were deposited4 ,in these ,irish sediments1 and others of the same age in ,belgium and elsewhere a few forms of land plants have been discovered2 but it is from the ,devonian rocks of ,north ,america that most of our knowledge of the flora of this period has been obtained4 ,,vi4 ,carboniferous4 ,from the point of view of palaeobotany1 the shales1 sandstones1 and seams of coal included in the ,carboniferous system are of special interest4 ,it is from the relics of this ,palaeozoic vegetation that the most important botanical lessons have been learnt4 ,the following classification of ,carboniferous rocks shows the order of succession of the various beds1 and the nature of the rocks which were formed at this stage in the ,earth's history4 ,upper ,coal-,measures4 ,coal-,measures#ec ,transition ,series4 ,middle ,coal-,measures4 ,lower ,coal-,measures4 ,millstone ,grit4 ,,carboniferous ,upper limestone shales and ,yoredale rocks4 ,carboniferous limestone ,carboniferous or series ,mountain limestone4 ,lower limestone shales4 ,basement conglomerate4 ,in the classification of ,carboniferous rocks adopted in ,geikie's text-book of ,geology the following arrangement is followed for the ,carboniferous limestone series#ed3-- ,yoredale group of shales and grits passing down into dark shales and limestones4 ,thick 7,scaur or ,main7 limestone in the south and centre of ,england and ,ireland1 passing northwards into sandstones1 shales and coals with limestones4 ,carboniferous ,lower limestone shale of the south and limestone series centre of ,england4 ,the ,calciferous sandstone group of ,scotland 7marine1 estuarine1 and terrestrial organisms7 probably represents the ,scaur limestone and lower limestone shale1 and graduates downwards insensibly into the ,upper ,old ,red ,sandstone4 ,the thick beds of mountain limestone1 with their characteristic marine fossil shells and corals play an important part in ,english scenery4 ,in ,derbyshire1 ,west ,yorkshire1 and other places1 the limestone crags and hills are made up of the raised floor of a comparatively deep ,carboniferous sea1 which covered a considerable portion of the ,british ,isles at the beginning of this epoch4 ,sidenote3 ,,carboniferous ,,rocks4 ,the accumulation of the calcareous skeletons of marine animals1 with masses of coral1 veritable shell-banks of extinct oyster-like lamellibranchs1 built up during the lapse of a long period of time1 formed widespread deposits of calcareous sediments4 ,these were eventually succeeded by less pure calcareous deposits1 the sea became shallower1 and land detritus found its way over an area formerly occupied by the clear waters of an open sea4 ,the shallowing process was gradually continued1 and the sea was by some means converted into a more confined fresh-water or brackish area1 in which were laid down many hundred feet of coarse sandy sediments derived from the waste of granitic highlands4 ,finally the conditions became less constant2 the continuous deposition of sandy detritus being interrupted by the more or less complete filling up of the area of sedimentation1 and the formation of a land surface which supported a luxuriant vegetation1 of which the dbris was subsequently converted into beds of coal4 ,by further subsidence the land was again submerged1 and the forest-covered area became overspread with sands and muds4 ,such are the imperfect outlines of the general physical conditions which are represented by the series of sedimentary strata included in the ,carboniferous system4 ,at the close of this period1 the ,earth's surface in ,western ,europe was subjected to crust-foldings on a large scale1 along lines running approximately ,north and ,south and ,east and ,west1 the two sets of movements resulting in the formation of ridges of ,carboniferous rocks4 ,the uppermost series of grits1 sandstones and coal-seams were in great part removed by denudation from the crests of the elevated ridges1 but remained in the intervening troughs or basins where they were less exposed to denudation4 ,it is the direct consequence of this1 that we have our ,coal-,measures preserved in the form of detached basins of upper ,carboniferous beds4 ,a closer examination of the comparative thickness and succession of ,carboniferous rocks in different parts of ,britain shows very clearly that in the northern area of ,scotland and in the ,north of ,england the conditions were different from those which obtained further ,south4 ,seeing how much palaeobotanical interest attaches to these rocks1 it is important to treat a little more fully of their geology4 ,in parts of ,devon1 ,cornwall and ,west ,somerset1 the ,devonian strata are succeeded by a series of folded and contorted rocks which have yielded a comparatively small number of ,carboniferous fossils4 ,to this succession of limestones1 shales and grits the term ,culm-,measures was applied by ,sedgwick and ,murchison in #ahcg4 ,the rocks of this series occupy a trough between the ,devonian rocks of ,north and ,south ,devon4 ,while some authorities have correlated the ,culm-,measures with the ,millstone ,grit1 others regard them as representing a portion of the true ,coal-,measures1 as well as the ,carboniferous and ,lower ,limestone ,shale#ee4 ,it has recently been shown that among the lower ,culm strata there occur bands of ancient deep-sea sediments1 consisting of beds of chert containing siliceous casts of various species of ,radiolaria4 ,there can be no doubt that the discovery of deep-sea fossils in this particular development of the ,british ,carboniferous system leads to the conclusion that 8while the massive deposits of the ,carboniferous limestone--formed of the skeletons of calcareous organisms--were in process of growth in the seas to the ,north1 there existed to the ,south-west a deeper ocean in which siliceous organisms predominated and formed these siliceous radiolarian rocks#ef40 ,the ,upper ,culm-,measures consist of conglomerates1 grits1 sandstones and shales with some plant remains and other fossils1 and constitute a typical set of shallow water sediments4 ,in ,westphalia1 the ,harz region1 ,thuringia1 ,silesia and ,moravia there are rocks corresponding to the ,culm-,measures of ,devon1 and some of these have also afforded evidence of deep water conditions4 ,sidenote3 ,,coal-,,measures4 ,s4 ,w4 ,england1 ,s4 ,wales1 ,derbyshire and ,yorkshire4 ,in these districts the ,carboniferous limestone reaches a considerable thickness2 in the ,mendips it has a thickness of #cjjj feet1 and in the ,pennine chain of #djjj feet4 ,at the base of this limestone series there occurs in the southern districts the so-called lower limestone shale1 consisting of clays1 shales and sandy beds4 ,above the limestone we have the ,millstone grit and ,coal-,measures2 but in the ,pennine district there is a series of rocks consisting of impure limestones and shales1 intercalated between the ,millstone grit and ,carboniferous limestone2 for this group of rocks the term ,yoredale series has been proposed4 ,in the ,isle of ,man and ,derbyshire sheets of lava are interbedded with the calcareous sediments1 affording clear proof of submarine volcanic eruptions4 ,n4 ,england and ,scotland4 ,in the ,carboniferous rocks of ,northumberland we have distinct indications of a shallower sea4 ,the regular succession of limestone strata in ,west ,yorkshire and other districts1 gives place to a series of thinner beds of limestones1 interstratified with shales and impure calcareous rocks4 ,we have come within the range of land detritus which was spread out on the floor of a shallow sea4 ,the lowest portion of the ,mountain limestone is here represented by about #bjj feet of shales and other rocks grouped together in the ,tuedian series4 ,the ,upper ,carboniferous limestone and ,yoredale rocks of ,yorkshire are represented by sandstones1 carbonaceous limestones and some seams of coal1 included in the ,bernician series4 ,further north1 again1 another classification has been proposed for the still more aberrant succession of rocks2 the lowest being spoken of as the ,calciferous sandstone1 and the upper as the ,carboniferous limestone4 ,the calciferous sandstone may be compared with the lower limestone shale and part of the ,carboniferous limestone of ,england4 ,the ,carboniferous limestone of ,scotland probably represents the upper part of the limestone of ,england and the ,yoredale rocks of the ,pennine and other areas4 ,turning to the upper members of the ,carboniferous system--in the ,coal-,measures1 as they were called in #ahag by ,william ,smith1--we have a series of coal seams1 sandstones1 shales1 and ironstones occurring for the most part in basin-shaped areas4 ,as a general rule1 each seam of coal1 which varies in thickness from one inch to thirty feet1 rests on a characteristic unstratified argillaceous rock known as ,underclay4 ,the accompanying diagram 7,fig4 #d7 illustrates the frequent intercalation of small bands of argillaceous and sandy rocks associated with the seams of coal4 ,the usual classification adopted for the ,british ,coal-,measures is that of ,upper1 ,middle1 and ,lower ,coal-,measures2 between the ,upper and ,middle divisions there occur certain transition or passage beds which are known as the ,transition series4 ,continental writers1 and more recently ,mr ,kidston of ,stirling1 have attempted with considerable success to correlate the ,coal-producing strata by means of fossil plants#eg4 ,illustration3 #aj in4 ,massive clay-shale with a few coal films in the lower part4 #aj in4 ,shale full of thin streaks of coal4 #ad in4 ,massive shale with a few streaks of coal and iron pyrites4 #e in4 ,bastard coal2 more coal than shale4 #f in4 ,good coal1 with masses of iron pyrites4 #a in4 ,coal and seat-rock mixed4 #e in4 ,seat-rock4 ,fig4 #d4 ,vertical section of the ,bassey or ,salts ,coal seam1 ,rushton ,colliery1 ,blackburn 7,lower ,coal-,measures74 ,from a specimen #d feet #d inches in height1 presented by ,mr ,p4 ,w4 ,pickup to the ,manchester ,museum1 ,owens ,college4 ,finally1 some reference must be made to the occurrence of ,carboniferous rocks underneath more recent strata4 ,in a geological map1 or bird's-eye view of a country1 we see such rocks as appear at the surface2 by means of deep borings1 however1 we are occasionally enabled to follow the course of older beds a considerable distance below the usually accessible part of the ,earth's crust4 ,in the neighbourhood of ,london1 ,dover1 and other places we have ,tertiary and ,mesozoic strata forming the surface of the country1 but below these comparatively recent formations1 the sinking of deep wells and other borings have proved the existence of a ridge of ,palaeozoic rocks stretching from the ,south ,wales ,coal-field through the ,south-east of ,england to northern ,france1 ,belgium and ,westphalia4 ,it is from rocks forming part of this old ridge that characteristic ,coal-,measure plants have been obtained from the ,dover boring4 ,in ,fig4 #e is shown an almost complete pinnule of ,neuropteris ,scheuchzeri ,hoffm41 a well-known fern1 marking a definite horizon of ,upper ,carboniferous rocks#eh4 ,the small hairs on the pinnules1 shown in the figure as fine lines lying more or less parallel to the midrib and across the lateral veins1 are a characteristic feature of this species4 ,illustration3 ,,fig4 #e4 ,imperfect pinnule of ,neuropteris ,scheuchzeri ,hoffm41 showing the characteristic hairs as fine lines traversing the lateral veins4 ,from a specimen obtained from the ,dover boring and now in the ,british ,museum4 ,nat4 size4 ,,vii4 ,permian4 ,reference has already been made to the earth-foldings which marked the close of ,carboniferous times2 8the open ,mediterranean sea of the ,carboniferous period in ,europe was converted into a large inland sea1 like the ,caspian of the present day1 surrounded by a rocky and hilly continent1 on which grew trees and plants of various kinds#ei40 ,in parts of ,lancashire1 ,westmoreland1 the ,eden ,valley1 and in the ,east of ,england from ,sunderland to ,nottingham1 there occurs a succession of limestones1 sandstones1 clays and other rocks with occasional beds of rock-salt and gypsum1 which represent the various forms of sediment and chemical precipitates formed on the floor of ,permian lakes4 ,the poverty of the fauna and flora of ,permian strata points to conditions unfavourable to life2 and there can be little doubt that the characteristic red rocks of ,st ,bees ,head1 and the creamy limestones of the ,durham coast are the upraised sediments of an inland salt-water lake4 ,the term ,dyas was proposed by ,marcou for this series of strata as represented in ,germany1 where the rocks are conveniently grouped in two series1 the ,magnesian limestone or ,zechstein and the red sandstones or ,rothliegendes4 ,the older and better known name of ,permian was instituted by ,murchison for the rocks of this age1 from their extreme development in the old kingdom of ,permia in ,russia4 ,unfortunately considerable confusion has arisen from the employment of different names for rocks of the same geological period2 and the grouping of the beds varies in different parts of the world4 ,it is of interest to note1 that in the ,tyrol1 ,carinthia1 and other places there are found patches of old marine beds which were originally laid down in an open sea1 which extended over the site of the ,mediterranean1 into ,russia and ,asia4 ,in ,bohemia1 the ,harz district1 ,autun in ,burgundy1 and other regions1 there are seams of ,permian coal interstratified with the marls and sands4 ,from these last named beds many fossil plants have been obtained1 and important palaeobotanical facts brought to light by the investigations of continental workers4 ,volcanic eruptions1 accompanied by lava streams and showers of ash1 have been recognised in the ,permian rocks of ,scotland1 and elsewhere4 ,in ,north ,america1 ,australia1 and ,india the term ,permo-,carboniferous is often made use of in reference to the continuous and regular sequence of beds which were formed towards the close of the ,carboniferous and into the succeeding ,permian epoch4 ,the enormous series of freshwater ,indian rocks1 to which geologists have given the name of the ,,gondwana ,,system1 includes the sediments of more than one geological period1 some of the older members being regarded as ,permo-,carboniferous in age4 ,these ,indian beds1 with others in ,australia1 ,south ,africa1 and ,south ,america1 are of special interest on account of the characteristic southern hemisphere plants which they have afforded1 and from the association with the fossiliferous strata of extensive boulder beds pointing to widespread glacial conditions4 ,,viii4 ,trias4 ,as we ascend the geologic series1 and pass up to the rocks overlying the ,permian deposits1 there are found many indications of a marked change in the records of animal and plant life4 ,many of the characteristic ,palaeozoic fossils are no longer represented1 and in their place we meet with fresh and in many cases more highly differentiated organisms4 ,the threefold division of the rocks of this period which suggested the term ,trias to those who first worked out the succession of the strata1 is typically illustrated over a wide area in ,germany1 in which the lowest or ,bunter series is followed by the calcareous ,muschelkalk1 and this again by the clays1 rock-salt1 and sandstones of the ,keuper series4 ,in the ,cheshire plain and in the low ground of the ,midlands1 we have a succession of red sandstones1 conglomerates1 and layers of rock-salt which correspond to the ,bunter and ,keuper beds of ,german geologists4 ,these ,triassic rocks were obviously formed in salt-water lakes1 in which from time to time long continued evaporation gave rise to extensive deposit of rock-salt and other minerals4 ,from the fact that it is this type of ,triassic sediments which was first made known1 it is often forgotten that the ,british and ,german rocks are not the typical representatives of this geological period4 ,the #8,alpine' ,trias of the ,mediterranean region1 in ,asia1 ,north ,america1 and other countries1 has a totally different facies1 and includes limestones and dolomites of deep-sea origin4 8,the widespread ,alpine ,trias is the pelagic facies of the formation2 the more restricted ,german ,trias1 on the other hand1 is a shallow shore1 bay or inland sea formation#fj40 ,in the ,keuper beds of southern ,sweden there are found workable seams of coal1 and the beds of this district have yielded numerous well-preserved examples of the ,triassic flora4 ,a more impure coal occurs in the lower ,keuper of ,thuringia and ,s4-,w4 ,germany1 and to this group of rocks the term ,lettenkohle is occasionally applied4 ,in the ,rhaetic ,alps of ,lombardy1 in the ,tyrol1 and in ,england1 from ,yorkshire to ,lyme ,regis1 ,devonshire1 ,somersetshire1 and other districts there are certain strata at the top of the ,triassic system known as the ,rhaetic or ,penarth beds4 ,the uppermost ,rhaetic beds1 often described as the ,white ,lias1 afford evidence of a change from the salt lakes of the ,trias to the open sea of the succeeding ,jurassic period4 ,passing beyond this period of salt lakes and wind-swept barren tracts of land1 we enter on another phase of the earth's history4 ,,ix4 ,jurassic4 ,the ,jura mountains of western ,switzerland consist in great part of folded and contorted rocks which were originally deposited on the floor of a ,jurassic sea4 ,in ,england the ,jurassic rocks are of special interest1 both for geological and historical reasons1 as it is in them that we find a rich fauna and flora of ,mesozoic age1 and it was the classification of these beds by means of their fossil contents that gained for ,william ,smith the title of the ,father of ,english ,geology4 ,a glance at a geological map of ,england shows a band of ,jurassic rocks stretching across from the ,yorkshire coast to ,dorset4 ,these are in a large measure calcareous1 argillaceous1 and arenaceous sediments of an open sea2 but towards the upper limit of the series1 both freshwater and terrestrial beds are met with4 ,numerous fragments of old coral reefs1 sea-urchins1 crinoids1 and other marine fossils are especially abundant2 in the freshwater beds and old surface-soils1 as well as in the marine sandstones and shales1 we have remnants of an exceedingly rich and apparently tropical vegetation4 ,this was an age of ,reptiles as well as an age of ,cycads4 ,an interesting feature of these widely distributed ,jurassic strata is the evidence they afford of distinct climatal zones2 there are clear indications1 according to the late ,dr ,neumayr1 of a ,mediterranean1 a middle ,european1 and a ,boreal or ,russian province#fa4 ,the subdivisions of the ,english ,jurassic rocks are as follows#fb3-- ,purbeck beds ,portland beds ,upper ,kimeridge clay ,corallian beds ,,jurassic ,oxford clay1 with ,middle ,oolite4 ,kellaways rock ,great ,oolite series ,lower ,inferior ,oolite series ,lias ,in tracing the several groups across ,england1 and into other parts of ,europe1 their characters are naturally found to vary considerably2 in one area a series is made up of typical clear water or comparatively deep sea sediments1 and in another we have shallow water and shore deposits of the same age4 ,the ,lias rocks have been further subdivided into zones by means of the species of ,ammonites which form so characteristic a feature of the ,jurassic fauna4 ,in the lower ,oolite strata there are shelly limestones1 clays1 sandstones1 and beds of lignite and ironstone4 ,without discussing the other subdivisions of the ,jurassic period1 we may note that in the uppermost members there are preserved patches of old surface-soils exposed in the face of the cliffs of the ,dorset coast and of the ,isle of ,portland4 ,x4 ,cretaceous4 ,in the south of ,england1 and in some other districts1 it is difficult to draw any definite line between the uppermost strata of the ,jurassic and the lowest of the ,cretaceous period4 ,the rocks of the so-called ,wealden series of ,kent1 ,surrey1 ,sussex1 and the ,isle of ,wight1 are usually classed as ,lower ,cretaceous1 but there is strong evidence in favour of regarding them as sediments of the ,jurassic period4 ,the ,cretaceous rocks of ,england are generally speaking parallel to the ,jurassic strata1 and occupy a stretch of country from the east of ,yorkshire and the ,norfolk coast to ,dorset in the south-west4 ,the ,chalk downs and cliffs represent the most familiar type of ,cretaceous strata4 ,in the white chalk with its numerous flints1 we have part of the elevated floor of a comparatively deep sea1 which extended in ,cretaceous times over a large portion of the east and south-east of ,england and other portions of the ,european continent4 ,on the bed of this sea1 beyond the reach of any river-borne detritus1 there accumulated through long ages the calcareous and siliceous remains of marine animals1 to be afterwards converted into chalk and flints4 ,at the beginning of the period1 however1 other conditions obtained1 and there extended over the south-east of ,england1 and parts of north and north-west ,germany and ,belgium1 a lake or estuary in which were built up deposits of clay1 sand and other material1 forming the delta of one or more large rivers4 ,for these sediments the name ,wealden was suggested in #ahbh4 ,eventually the gradual subsidence of this area led to an incursion of the sea1 and the delta became overflowed by the waters of a large ,cretaceous sea4 ,at first the sea was shallow1 and in it were laid down coarse sands and other sediments known as the ,lower ,greensand rocks4 ,by degrees1 as the subsidence continued1 the shallows became deep water1 and calcareous material slowly accumulated1 to be at last upraised as beds of white chalk4 ,the distribution of fossils in the ,cretaceous rocks of north and south ,europe distinctly points to the existence of two fairly well-marked sets of organisms in the two regions2 no doubt the expression of climatal zones similar to those recognised in ,jurassic times4 ,in ,north ,america1 ,cretaceous rocks are spread over a wide area1 also in ,north ,africa1 ,india1 ,south ,africa1 and other parts of the world4 ,within the ,arctic ,circle strata of this age have become famous1 chiefly on account of the rich flora described from them by the ,swiss palaeobotanist ,heer4 ,the fauna and flora of this epoch are alike in their advanced state of development and in the great variety of specific types2 the highest class of plants is first met with at the base of the ,cretaceous system4 ,,xi4 ,tertiary4 8,at the close of the ,chalk age a change took place both in the distribution of land and water1 and also in the development of organic life1 so great and universal1 that it has scarcely been equalled at any other period of the earth's geological history#fc40 ,the ,tertiary period seems to bring us suddenly to the threshold of our own times4 ,in ,england at least1 the deposits of this age are of the nature of loose sands1 clays and other materials containing shells1 bones1 and fossil plants bearing a close resemblance to organisms of the present era4 ,the chalk rocks1 upheaved from the ,cretaceous sea1 stood out as dry land over a large part of ,britain2 much of their material was in time removed by the action of denuding agents1 and the rest gradually sank again beneath the waters of ,tertiary lakes and estuaries4 ,in the south of ,england1 and in north ,europe generally1 the ,tertiary rocks have suffered but little disturbance or folding1 but in southern ,europe and other parts of the world1 the ,tertiary sands have been compacted and hardened into sandstones1 and involved in the gigantic crust-movements which gave birth to many of our highest mountain chains4 ,the ,alps1 ,carpathians1 ,apennines1 ,himalayas1 and other ranges consist to a large extent of piled up and strangely folded layers of old ,tertiary sediments4 ,the volcanic activity of this age was responsible for the basaltic lavas of the ,giants' ,causeway1 the ,isle of ,staffa1 and other parts of western ,scotland4 ,during the succeeding phases of this period1 the distribution of land and sea was continually changing1 climatic conditions varied within wide limits2 and in short wherever ,tertiary fossiliferous beds occur1 we find distinct evidence of an age characterised by striking activity both as regards the action of dynamical as well as of organic forces4 ,sir ,charles ,lyell proposed a subdivision of the strata of this period into ,eocene1 ,miocene1 and ,pliocene1 founding his classification on the percentage of recent species of molluscs contained in the various sets of rocks4 ,his divisions have been generally adopted4 ,in #ahed ,prof4 ,beyrich proposed to include another subdivision in the ,tertiary system1 and to this he gave the name ,oligocene4 ,occupying a basin-shaped area around ,london and ,paris there are beds of ,eocene sands and clays which were originally deposited as continuous sheets of sediment in water at first salt1 afterwards brackish and to a certain extent fresh4 ,in the ,hampshire cliffs and in some parts of the ,isle of ,wight1 we have other patches of these oldest ,tertiary sediments4 ,across the south of ,europe1 ,north ,africa1 ,arabia1 ,persia1 the ,himalayas1 to ,java and the ,philippine islands1 there existed in early ,tertiary times a wide sea connecting the ,atlantic and ,pacific oceans2 and it may be that in the ,mediterranean of to-day we have a remnant of this large ,eocene ocean4 ,later in the ,tertiary period a similar series of beds was deposited which we now refer to as the ,oligocene strata2 such occurs in the cliffs of ,headon hill in the ,isle of ,wight1 containing bones of crocodiles1 and turtles1 with the relics of a rich flora preserved in the delta deposits of an ,oligocene river4 ,at a still later stage the ,british area was probably dry land1 and an open sea existed over the ,mediterranean region4 ,in the neighbourhood of ,vienna we have beds of this age represented by a succession of sediments1 at first marine and afterwards freshwater4 ,miocene beds occur over a considerable area in ,switzerland and the ,arctic regions1 and they have yielded a rich harvest to palaeobotanical investigators4 ,on the coast of ,essex1 ,suffolk1 ,norfolk1 the south of ,cornwall1 and other districts there occur beds of shelly sand and gravel long known under the name of #8,crag4' ,the beds have a very modern aspect2 the sands have not been converted into sandstones1 and the shells have undergone but little change4 ,these materials were for the most part accumulated on the bed of a shallow sea which swept over a portion of ,east ,anglia in ,pliocene times4 ,in the sediments of this age northern forms of shells and other organisms make their appearance1 and in the ,cromer forest-bed there occur portions of drifted trees with sands1 clays and gravels1 representing in all probability the dbris thrown down on the banks of an ancient river4 ,at this time the greater part of the ,north ,sea was probably a low-lying forest-covered region1 through which flowed the waters of a large river1 of which part still exists in the modern ,rhine4 ,the lowering of temperature which became distinctly pronounced in the ,pliocene age1 continued until the greater part of ,britain and north ,europe experienced a glacial period1 and such conditions obtained as we find to-day in ice-covered ,greenland4 ,finally the ice-sheet melted1 the local glaciers of ,north ,wales1 the ,english ,lake district and other hilly regions1 retreated1 and after repeated alterations in level1 the land of ,great ,britain assumed its modern form4 ,the submerged forests and peat beds familiar in many parts of the coast1 the diatomaceous deposits of dried up lakes1 8remain as the very finger touches of the last geological change40 ,sidenote3 ,,geological ,,evolution4 ,the agents of change and geological evolution1 which we have passed in brief review1 are still constantly at work carrying one step further the history of the earth4 ,a superficial review of geological history gives us an impression of recurring and widespread convulsions1 and rapidly effected revolutions in organic life and geographical conditions2 on the other hand a closer comparison of the past and present1 with due allowance for the enormous period of time represented by the records of the rocks1 helps us to realise the continuity of geological evolution4 8,so that within the whole of the immense period indicated by the fossiliferous stratified rocks1 there is assuredly not the slightest proof of any break in the uniformity of ,nature's operations1 no indication that events have followed other than a clear and orderly sequence#fd40 ,,chapter ,,iv4 ,,the ,,preservation ,,of ,,plants ,,as ,,fossils4 8,the things1 we know1 are neither rich nor rare1 ,but wonder how the devil they got there40 ,,pope1 ,prologue to the ,satires4 ,the discovery of a fossil1 whether as an impression on the surface of a slab of rock or as a piece of petrified wood1 naturally leads us back to the living plant1 and invites speculation as to the circumstances which led to the preservation of the plant fragment4 ,there is a certain fascination in endeavouring1 with more or less success1 to picture the exact conditions which obtained when the leaf or stem was carried along by running water and finally sealed up in a sedimentary matrix4 ,attempts to answer the question--,how came the plant remains to be preserved as fossils8--are not merely of abstract interest appealing to the imagination1 but are of considerable importance in the correct interpretation of the facts which are to be gleaned from the records of plant-bearing strata4 ,before describing any specific examples of the commoner methods of fossilisation2 we shall do well to briefly consider how plants are now supplying material for the fossils of a future age4 ,in the great majority of cases1 an appreciation of the conditions of sedimentation1 and of the varied circumstances attending the transport and accumulation of vegetable dbris1 supplies the solution of a problem akin to that of the fly in amber and the manner in which it came there4 ,sidenote3 ,,old ,,surface-,,soils4 ,seeing that the greater part of the sedimentary strata have been formed in the sea1 and as the sea rather than the land has been for the most part the scene of rock-building in the past1 it is not surprising that fossil plants are far less numerous than fossil animals4 ,with the exception of the algae and a few representatives of other classes of plants1 which live in the shallow-water belt round the coast1 or in inland lakes and seas1 plants are confined to land-surfaces2 and unless their remains are swept along by streams and embedded in sediments which are accumulating on the sea floor1 the chance of their preservation is but small4 ,the strata richest in fossil plants are often those which have been laid down on the floor of an inland lake or spread out as river-borne sediment under the waters of an estuary4 ,unlike the hard endo- and exo-skeletons of animals1 the majority of plants are composed of comparatively soft material1 and are less likely to be preserved or to retain their original form when exposed to the wear and tear which must often accompany the process of fossilisation4 ,the ,coal-,measure rocks have furnished numberless relics of a ,palaeozoic vegetation1 and these occur in various forms of preservation in rocks laid down in shallow water on the edge of a forest-covered land4 ,the underclays or unstratified argillaceous beds which nearly always underlie each seam of coal have often been described as old surface-soils1 containing numerous remains of roots and creeping underground stems of forest trees4 ,the overlying coal has been regarded as a mass of the carbonised and compressed dbris of luxuriant forests which grew on the actual spot now occupied by the beds of coal4 ,there are1 however1 many arguments in favour of regarding the coal seams as beds of altered vegetable material which was spread out on the floor of a lagoon or lake1 while the underclay was an old soil covered by shallow water or possibly a swampy surface tenanted by marsh-loving plants#fe4 ,the ,jurassic beds of the ,yorkshire ,coast1 long famous as some of the richest plant-bearing strata in ,britain1 and the ,wealden rocks of the south coast afford examples of ,mesozoic sediments which were laid down on the floor of an estuary or large lake4 ,circumstances have occasionally rendered possible the preservation of old land-surfaces with the stumps of trees still in their position of growth4 ,one of the best examples of this in ,britain are the so-called dirt-beds or black bands of ,portland and the ,dorset ,coast4 ,on the cliffs immediately east of ,lulworth ,cove1 the surface of a ledge of ,purbeck limestone which juts out near the top of the cliffs1 is seen to have the form here and there of rounded projecting bosses or #8,burrs' several feet in diameter4 ,in the centre of each boss there is either an empty depression1 or the remnants of a silicified stem of a coniferous tree4 ,blocks of limestone #c to #e feet long and of about equal thickness may be found lying on the rocky ledge presenting the appearance of massive sarcophagi in which the central trough still contains the silicified remains of an entombed tree4 ,the calcareous sediment no doubt oozed up to envelope the thick stem as it sank into the soft mud4 ,an examination of the rock just below the bed bearing these curious circular elevations reveals the existence of a comparatively narrow band of softer material1 which has been worn away by denuding agents more rapidly than the overlying limestone4 ,this band consists of partially rounded or subangular stones associated with carbonaceous material1 and probably marks the site of an old surface-soil4 ,this old soil is well shown in the cliffs and quarries of ,portland1 and similar dirt-beds occur at various horizons in the ,lower and ,middle ,purbeck ,series#ff4 ,in this case1 then1 we have intercalated in a series of limestone beds containing marine and freshwater shells two or three plant beds containing numerous and frequently large specimens of cycadean and coniferous stems1 lying horizontally or standing in their original position of growth4 ,these are vestiges of an ancient forest which spread over a considerable extent of country towards the close of the ,jurassic period4 ,the trunks of cycads1 long familiar in the ,isle of ,portland as fossil crows' nests1 have usually the form of round depressed stems with the central portion somewhat hollowed out4 ,it was supposed by the quarrymen that they were petrified birds' nests which had been built in the forks of the trees which grew in the ,portland forest4 ,the beds separating the surface-soils of the ,purbeck ,series1 as seen in the sections exposed on the cliffs or quarries1 point to the subsidence of a forest-covered area over which beds of water-borne sediment were gradually deposited1 until in time the area became dry land and was again taken possession of by a subtropical vegetation1 to be once more depressed and sealed up under layers of sediment#fg4 ,a still more striking example of the preservation of forest trees rooted in an old surface-soil is afforded by the so-called fossil-grove in ,victoria ,park1 ,glasgow1 7,frontispiece74 ,the stumps of several trees1 varying in diameter from about one to three feet1 are fixed by long forking #8roots' in a bed of shale4 ,in some cases the spreading #8roots1' which bear the surface features of ,stigmaria1 extend for a distance of more than ten feet from the base of the trunk4 ,the stem surface is marked by irregular wrinklings which suggest a fissured bark2 but the superficial characters are very imperfectly preserved4 ,in one place a flattened ,lepidodendron stem1 about #cj feet long1 lies prone on the shale4 ,each of the rooted stumps is oval or elliptical in section1 and the long axes of the several stems are approximately parallel1 pointing to some cause operating in a definite direction which gave to the stems their present form4 ,near one of the trees1 and at a somewhat higher level than its base1 the surface of the rock is clearly ripple-marked1 and takes us back to the time when the sinking forest trees were washed by waves which left an impress in the soft mud laid down over the submerged area4 ,the stumps appear to be those of ,lepidodendron trees1 rooted in ,lower ,carboniferous rocks4 ,from their manner of occurrence it would seem that we have in them a corner of a ,palaeozoic forest in which ,lepidodendra played a conspicuous part4 ,the shales and sandstones containing the fossil trees were originally overlain by a bed of igneous rock which had been forced up as a sheet of lava into the hardened sands and clays#fh4 ,other examples of old surface-soils occur in different parts of the world and in rocks of various ages4 ,as an instance of a land surface preserved in a different manner1 reference may be made to the thin bands of reddish or brown material as well as clays and shale which occasionally occur between the sheets of ,tertiary lava in the ,western ,isles of ,scotland and the north-east of ,ireland4 ,in the intervals between successive outpourings of basaltic lava in the north-west of ,europe during the early part of the ,tertiary period1 the heated rocks became gradually cooler1 and under the influence of weathering agents a surface-soil was produced fit for the growth of plants4 ,in some places1 too1 shallow lakes were formed1 and leaves1 fruits and twigs became embedded in lacustrine sediments1 to be afterwards sealed up by later streams of lava4 ,in the face of the cliff at ,ardtun ,head on the coast of ,mull a leaf-bed is exposed between two masses of gravel underlying a basaltic lava flow2 the impressions of the leaves of ,gingko and other plants from the ,tertiary sediments of this district are exceptionally beautiful and well preserved#fi4 ,a large collection obtained by ,mr ,starkie ,gardner may be seen in the ,british ,museum4 ,in #ahhc the ,malayan island of ,krakatoa1 #bj miles from ,sumatra and ,java1 was the scene of an exceptionally violent volcanic explosion4 ,two-thirds of the island were blown away1 and the remnant was left absolutely bare of organic life4 ,in #ahhf it was found that several plants had already established themselves on the hardened and weathered crust of the ,krakatoan rocks1 the surface of the lavas having been to a large extent prepared for the growth of the higher plants by the action of certain blue-green algae which represent some of the lowest types of plant life#gj4 ,we may perhaps assume a somewhat similar state of things to have existed in the volcanic area in north-west ,europe1 where the intervals between successive outpourings of lava are represented by the thin bands of leaf-beds and old surface-soils4 ,on the ,cheshire ,coast at ,leasowe#ga and other localities1 there is exposed at low water a tract of black peaty ground studded with old rooted stumps of conifers and other trees 7fig4 #f74 ,there is little reason to doubt that at all events the majority of the trees are in their natural place of growth4 ,the peaty soil on which they rest contains numerous flattened stems of reeds and other plants1 and is penetrated by roots1 probably of some aquatic or marshy plants which spread over the site of the forest as it became gradually submerged4 ,a lower forest-bed rests directly on a foundation of boulder clay4 ,such submerged forests are by no means uncommon around the ,british coast2 many of them belong to a comparatively recent period1 posterior to the glacial age4 ,in many cases1 however1 the tree stumps have been drifted from the places where they grew and eventually deposited in their natural position1 the roots of the trees1 in some cases aided by stones entangled in their branches1 being heavier than the stem portion4 ,there is a promising field for botanical investigation in the careful analysis of the floras of submerged forests2 the work of ,clement ,reid1 ,nathorst1 ,andersson and others1 serves to illustrate the value of such research in the hands of competent students4 ,illustration3 ,,fig4 #f4 ,part of a submerged ,forest seen at low water on the ,cheshire ,coast at ,leasowe4 ,drawn from a photograph4 ,the following description by ,lyell1 taken from his ,american travels1 is of interest as affording an example of the preservation of a surface-soil3 8,on our way home from ,charleston1 by the railway from ,orangeburg1 ,i observed a thin black line of charred vegetable matter exposed in the perpendicular section of the bank4 ,the sand cast out in digging the railway had been thrown up on the original soil1 on which the pine forest grew2 and farther excavations had laid open the junction of the rubbish and the soil4 ,as geologists1 we may learn from this fact how a thin seam of vegetable matter1 an inch or two thick1 is often the only monument to be looked for of an ancient surface of dry land1 on which a luxuriant forest may have grown for thousands of years4 ,even this seam of friable matter may be washed away when the region is submerged1 and1 if not1 rain water percolating freely through the sand may1 in the course of ages1 gradually carry away the carbon#gb40 ,sidenote3 ,,fossil ,,wood4 ,in addition to the remnants of ancient soils1 and the preservation of plant fragments in rocks which have been formed on the floor of an inland lake or an estuary1 it is by no means rare to find fossil plants in obviously marine sediments4 ,in fig4 #g we have a piece of coniferous wood with the shell of an ,ammonite 7,aegoceras planicosta ,sow47 lying on it2 the specimen was found in the ,lower ,lias clay at ,lyme ,regis1 and illustrates the accidental association of a drifted piece of a forest tree with a shell which marks at once the age and the marine character of the beds4 ,again in fig4 #h we have a block of flint partially enclosing a piece of coniferous wood in which the internal structure has been clearly preserved in silica4 ,this specimen was found in the chalk1 a deposit laid down in the clear and deep water of the ,cretaceous sea4 ,the wood must have floated for some time before it became water-logged and sank to the sea-floor4 ,in the light coloured wood there occur here and there dark spots which mark the position of siliceous plugs b1 b filling up clean cut holes bored by ,teredos in the woody tissue4 ,the wood became at last enclosed by siliceous sediment and its tissues penetrated by silica in solution1 which gradually replaced and preserved in wonderful perfection the form of the original tissue4 ,a similar instance of wood enclosed in flint was figured by ,mantell in #ahdd in his ,medals of ,creation#gc4 ,illustration3 ,,fig4 #g4 ,aegoceras planicosta ,sow4 on a piece of coniferous wood1 ,lower ,lias1 ,lyme ,regis4 ,from a specimen in the ,british ,museum4 ,slightly reduced4 ,illustration3 ,,fig4 #h4 ,piece of coniferous wood in flint1 from the ,chalk1 ,croydon4 ,drawn from a specimen presented to the ,british ,museum by ,mr ,murton ,holmes4 ,in the side view1 shown above in the figure1 the position of the wood is shown by the lighter portion1 with holes1 b1 b1 bored by ,teredos or some other wood-eating animal4 ,in the end view1 below1 the wood is seen as an irregular cylinder w1 w1 embedded in a matrix of flint4 ,nat4 size4 ,the specimen represented in fig4 #i illustrates the almost complete destruction of a piece of wood by some boring animal4 ,the circular and oval dotted patches represent the filled up cavities made by a ,teredo or some similar wood-boring animal4 ,illustration3 ,,fig4 #i4 ,piece of wood from the ,red ,crag of ,suffolk1 riddled with holes filled in with mud4 ,from a specimen in the ,york ,museum4 ,nat4 size4 ,sidenote3 ,,conditions ,,of ,,fossilisation4 ,before discussing a few more examples of fossils illustrating different methods of fossilisation1 it may not be out of place to quote a few extracts from travellers' narratives which enable us to realise more readily the circumstances and conditions under which plant remains have been preserved in the ,earth's crust4 ,in an account of a journey down the ,rawas river in ,sumatra1 ,forbes thus describes the flooded country3-- 8,the whole surface of the water was covered1 absolutely in a close sheet1 with petals1 fruits and leaves1 of innumerable species4 ,in placid corners sometimes ,i noted a collected mass nearly half a foot deep1 among which1 on examination1 ,i could scarcely find a leaf that was perfect1 or that remained attached to its rightful neighbour1 so that were they to become imbedded in some soft muddy spot1 and in after ages to reappear in a fossil form they would afford a few difficult puzzles to the palaeontologist1 both to separate and to put together#gd40 ,an interesting example of the mixture of plants and animals in sedimentary deposits is described by ,hooker in his ,himalayan ,journals3-- 8,to the geologist the ,jheels and ,sunderbunds are a most instructive region1 as whatever may be the mean elevation of their waters1 a permanent depression of ten to fifteen feet would submerge an immense tract1 which the ,ganges1 ,burrampooter1 and ,soormah would soon cover with beds of silt and sand4 8,there would be extremely few shells in the beds thus formed1 the southern and northern divisions of which would present two very different floras and faunas1 and would in all probability be referred by future geologists to widely different epochs4 ,to the north1 beds of peat would be formed by grasses1 and in other parts temperate and tropical forms of plants and animals would be preserved in such equally balanced proportions as to confound the palaeontologist2 with the bones of the long-snouted alligator1 ,gangetic porpoise1 ,indian cow1 buffalo1 rhinoceros1 elephant1 tiger1 deer1 bear1 and a host of other animals1 he would meet with acorns of several species of oak1 pine-cones and magnolia fruits1 rose seeds1 and ,cycas nuts1 with palm nuts1 screw-pines1 and other tropical productions#ge40 ,in another place the same author writes3 8,on the #abth of ,january1 #ahdh1 the ,moozuffer was steaming amongst the low1 swampy islands of the ,sunderbunds4444 ,every now and then the paddles of the steamer tossed up the large fruits of ,nypa fruticans1 ,thunb41 a low stemless palm that grows in the tidal waters of the ,indian ,ocean1 and bears a large head of nuts4 ,it is a plant of no interest to the common observer1 but of much to the geologist1 from the nuts of a similar plant abounding in the ,tertiary formations at the mouth of the ,thames1 having floated about there in as great profusion as here1 till buried deep in the silt and mud that now forms the island of ,sheppey#gf40 ,sidenote3 ,,drifting ,,of ,,trees4 ,of the drifting of timber1 fruits1 c41 we find numerous accounts in the writings of travellers4 ,rodway thus describes the formation of vegetable rafts in the rivers of ,northern ,british ,guiana3-- 8,sometimes a great tree1 whose timber is light enough to float1 gets entangled in the grass1 and becomes the nucleus of an immense raft1 which is continually increasing in size as it gathers up everything that comes floating down the river#gg40 ,the undermining of river banks in times of flood1 and the transport of the drifted trees to be eventually deposited in the delta is a familiar occurrence in many parts of the world4 ,the more striking instances of such wholesale carrying along of trees are supplied by ,bates1 ,lyell and other writers4 ,in his description of the ,amazon the former writes3 8,the currents ran with great force close to the bank1 especially when these receded to form long bays or enseadas1 as they are called1 and then we made very little headway4 ,in such places the banks consist of loose earth1 a rich crumbling vegetable mould1 supporting a growth of most luxuriant forest1 of which the currents almost daily carry away large portions1 so that the stream for several yards out is encumbered with fallen trees1 whose branches quiver in the current#gh40 ,in another place1 ,bates writes3 8,the rainy season had now set in over the region through which the great river flows2 the sand-banks and all the lower lands were already under water1 and the tearing current1 two or three miles in breadth1 bore along a continuous line of uprooted trees and islets of floating plants#gi40 ,the rafts of the ,mississippi and other rivers described by ,lyell afford instructive examples of the distant transport of vegetable material4 ,the following passage is taken from the ,principles of ,geology2 8,within the tropics there are no ice-floes2 but1 as if to compensate for that mode of transportation1 there are floating islets of matted trees1 which are often borne along through considerable spaces4 ,these are sometimes seen sailing at the distance of fifty or one hundred miles from the mouth of the ,ganges1 with living trees standing erect upon them4 ,the ,amazons1 the ,orinoco1 and the ,congo also produce these verdant rafts#hj40 ,after describing the enormous natural rafts of the ,atchafalaya1 an arm of the ,mississippi1 and of the ,red river1 ,lyell goes on to say3 8,the prodigious quantity of wood annually drifted down by the ,mississippi and its tributaries is a subject of geological interest1 not merely as illustrating the manner in which abundance of vegetable matter becomes1 in the ordinary course of nature1 imbedded in submarine and estuary deposits1 but as attesting the constant destruction of soil and transportation of matter to lower levels by the tendency of rivers to shift their courses4444 ,it is also found in excavating at ,new ,orleans1 even at the depth of several yards below the level of the sea1 that the soil of the delta contains innumerable trunks of trees1 layer above layer1 some prostrate as if drifted1 others broken off near the bottom1 but remaining still erect1 and with their roots spreading on all sides1 as if in their natural position#ha40 ,the drifting of trees in the ocean is recorded by ,darwin in his description of ,keeling ,island1 and their action as vehicles for the transport of boulders is illustrated by the same account4 8,in the channels of ,tierra del ,fuego large quantities of drift timber are cast upon the beach1 yet it is extremely rare to meet a tree swimming in the water4 ,these facts may possibly throw light on single stones1 whether angular or rounded1 occasionally found embedded in fine sedimentary masses#hb40 ,fruits may often be carried long distances from land1 and preserved in beds far from their original source4 ,whilst cruising amongst the ,solomon ,islands1 the ,challenger met with fruits of ,barringtonia speciosa c41 #acj-aej miles from the coast4 ,off the coast of ,new ,guinea long lines of drift wood were seen at right angles to the direction of the river2 uprooted trees1 logs1 branches1 and bark1 often floating separately4 8,the midribs of the leaves of a pinnate-leaved palm were abundant1 and also the stems of a large cane grass 7,saccharum71 like that so abundant on the shores of the great river in ,fiji4 ,various fruits of trees and other fragments were abundant1 usually floating confined in the midst of the small aggregations into which the floating timber was everywhere gathered4444 ,leaves were absent except those of the ,palm1 on the midrib of which some of the pinn were still present4 ,the leaves evidently drop first to the bottom1 whilst vegetable drift is floating from a shore2 thus1 as the dbris sinks in the sea water1 a deposit abounding in leaves1 but with few fruits and little or no wood1 will be formed near shore1 whilst the wood and fruits will sink to the bottom farther off the land4 ,much of the wood was floating suspended vertically in the water1 and most curiously1 logs and short branch pieces thus floating often occurred in separate groups apart from the horizontally floating timber4 ,the sunken ends of the wood were not weighted by any attached masses of soil or other load of any kind2 possibly the water penetrates certain kinds of wood more easily in one direction with regard to its growth than the other1 hence one end becomes water-logged before the other4444 ,the wood which had been longest in the water was bored by a ,pholas#hc40 ,the bearing of this account on the manner of preservation of fossils1 and the differential sorting so frequently seen in plant beds1 is sufficiently obvious4 ,as another instance of the great distance to which land plants may be carried out to sea and finally buried in marine strata1 an observation by ,bates may be cited4 ,when #djj miles from the mouth of the main ,amazons1 he writes3 8,we passed numerous patches of floating grass mingled with tree trunks and withered foliage4 ,amongst these masses ,i espied many fruits of that peculiar ,amazonian tree the ,ubuss ,palm2 this was the last ,i saw of the great river#hd40 ,the following additional extract from the narrative of the ,cruise of ,h4,m4,s4 ,challenger illustrates in a striking degree the conflicting evidence which the contents of fossiliferous beds may occasionally afford2 it describes what was observed in an excursion from ,sydney to ,berowra ,creek1 a branch of the main estuary or inlet into which flows the ,hawkesbury river4 ,it was impossible to say where the river came to an end and the sea began4 ,the ,creek is described as a long tortuous arm of the sea1 #aj to #ae miles long1 with the side walls covered with orchids and ,platycerium4 ,the ferns and palms were abundant in the lateral shady glens2 marine and inland animals lived in close proximity4 8,here is a narrow strip of the sea water1 twenty miles distant from the open sea2 on a sandy shallow flat close to its head are to be seen basking in the sun numbers of sting-rays4444 ,all over these flats1 and throughout the whole stretch of the creek1 shoals of ,grey ,mullet are to be met with2 numerous other marine fish inhabit the creek4 ,porpoises chase the mullet right up to the commencement of the sand-flat4 ,at the shores of the creek the rocks are covered with masses of excellent oysters and mussel1 and other shell-bearing molluscs are abundant1 whilst a small crab is to be found in numbers in every crevice4 ,on the other hand the water is overhung by numerous species of forest trees1 by orchids and ferns1 and other vegetation of all kinds2 mangroves grow only in the shallow bays4 ,the gum trees lean over the water in which swim the ,trygon and mullet1 just as willows hang over a pool of carp4 ,the sandy bottom is full of branches and stems of trees1 and is covered in patches here and there by their leaves4 ,insects constantly fall in the water1 and are devoured by the mullet4 ,land birds of all kinds fly to and fro across the creek1 and when wounded may easily be drowned in it4 ,wallabies swim across occasionally1 and may add their bones to the dbris at the bottom4 ,hence here is being formed a sandy deposit1 in which may be found cetacean1 marsupial1 bird1 fish1 and insect remains1 together with land and sea shells1 and fragments of a vast land flora2 yet how restricted is the area occupied by this deposit1 and how easily might surviving fragments of such a record be missed by future geological explorers6#he0 ,sidenote3 ,,meaning ,,of ,,the ,,term #8,,fossil4' ,the term #8fossil' suggests to the lay mind a petrifaction or a replacement by mineral matter of the plant tissues4 ,in the scientific sense1 a fossil plant1 that is a plant or part of a plant whether in the form of a true petrifaction or a structureless mould or cast1 which has been buried in the earth by natural causes1 may be indistinguishable from a piece of recent wood lately fallen from the parent tree4 ,in the geologically recent peat beds such little altered fossils 7or sub-fossils7 are common enough1 and even in older rocks the more resistant parts of plant fragments are often found in a practically unaltered state4 ,in the leaf impressions on an impervious clay1 the brown-walled epidermis shows scarcely any indication of alteration since it was deposited in the soft mud of a river's delta4 ,such fossil leaves are common in the ,english ,tertiary beds1 and even in ,palaeozoic rocks it is not uncommon to find an impression of a plant on a bed of shale from which the thin brown epidermis may be peeled off the rock1 and if microscopically examined it will be found to have retained intact the contours of the cuticularised epidermal cells4 ,a striking example of a similar method of preservation is afforded by the so-called paper-coal of ,culm age from the ,province of ,toula in ,russia#hf4 ,in the ,russian area the ,carboniferous or ,permian rocks have been subjected to little lateral pressure1 and unlike the beds of the same age in ,western ,europe1 they have not been folded and compressed by widespread and extensive crust-foldings4 ,instead of the hard seams of coal there occur beds of a dark brown laminated material1 made up very largely of the cuticles of ,lepidodendroid plants4 ,from such examples we may naturally pass to fossils in which the plant structure has been converted into carbonaceous matter or even pure coal4 ,this form of preservation is especially common in plant-bearing beds at various geological horizons4 ,in other cases1 again1 some mineral solution1 oxide of iron1 talc1 and other substances1 has replaced the plant tissues4 ,from the ,coal-,measures of ,switzerland ,heer has figured numerous specimens of fern fronds and other plants in which the leaf form has been left on the dark coloured rock surface as a thin layer of white talcose material#hg4 ,in the ,buntersandstone of the ,vosges and other districts the red imperfectly preserved impressions of plant stems and leaves are familiar fossils#hh2 the carbonaceous substance of the tissues has been replaced by a brown or red oxide of iron4 ,sidenote3 ,,incrustations4 ,plants frequently occur in the form of incrustations2 and in fact incrustations1 which may assume a variety of forms1 are the commonest kind of fossil4 ,the action of incrusting springs1 or as they are often termed petrifying springs1 is illustrated at ,knaresborough1 in ,yorkshire1 and many other places where water highly charged with carbonate of lime readily deposits calcium carbonate on objects placed in the path of the stream4 ,the travertine deposited in this manner forms an incrustation on plant fragments1 and if the vegetable substance is subsequently removed by the action of water or decay1 a mould of the embedded fragment is left in the calcareous matrix4 ,an instructive example of this form of preservation was described in #ahfhhi by ,sharpe from an old gravel pit near ,northampton4 ,he found in a section eight feet high 7fig4 #aj71 a mass of incrusted plants of ,chara 7a7 resting on and overlain by a calcareous paste 7c7 and 7d7 made up of the decomposed material of the overlying rock1 and this again resting on sand4 ,the place where the section occurred was originally the site of a pool in which ,stoneworts grew in abundance4 ,large blocks of these incrusted ,charas may be seen in the fossil-plant gallery of the ,british ,museum4 ,illustration3 ,,fig4 #aj4 ,section of an old pool filled up with a mass of ,chara4 7,from the ,geol4 ,mag4 vol4 v4 #ahfh1 p4 #efc47 ,in the ,natural ,history ,museum in the ,jardin des ,plantes1 ,paris1 one of the table-cases contains what appear to be small models of flowers in green wax4 ,these are in reality casts in wax of the moulds or cavities left in a mass of calcareous travertine1 on the decay and disappearance of the encrusted flowers and other plant fragments#ij4 ,this porous calcareous rock occurs near ,szanne in ,southern ,france1 and is of ,eocene age#ia4 ,the plants were probably blown on to the freshly deposited carbonate of lime1 or they may have simply fallen from the tree on to the incrusting matrix2 more material was afterwards deposited and the flowers were completely enclosed4 ,eventually the plant substance decayed1 and as the matrix hardened moulds were left of the vegetable fragments4 ,wax was artificially forced into these cavities and the surrounding substance removed by the action of an acid1 and thus perfect casts were obtained of ,tertiary flowers4 ,darwin has described the preservation of trees in ,van ,diemen's land by means of calcareous substances4 ,in speaking of beds of blown sand containing branches and roots of trees he says3 8,the whole became consolidated by the percolation of calcareous matter2 and the cylindrical cavities left by the decaying of the wood were thus also filled up with a hard pseudo-stalactitical stone4 ,the weather is now wearing away the softer parts1 and in consequence the hard casts of the roots and branches of the trees project above the surface1 and1 in a singularly deceptive manner1 resemble the stumps of a dead thicket#ib40 ,as a somewhat analogous method of preservation to that in travertine1 the occurrence of plants in amber should be mentioned4 ,in ,eocene times there existed over a region1 part of which is now the ,north-east ,german coast1 an extensive forest of conifers and other trees4 ,some of the conifers were rich in resinous secretions which were poured out from wounded surfaces or from scars left by falling branches4 ,as these flowed as a sticky mass over the stem or collected on the ground1 flowers1 leaves1 and twigs blown by the wind or falling from the trees1 became embedded in the exuded resin4 ,evaporation gradually hardened the resinous substance until the plant fragments became sealed up in a mass of amber1 in precisely the same manner in which objects are artificially preserved in ,canada balsam4 ,in many cases the amber acts as a petrifying agent1 and by penetrating the tissues of a piece of wood it preserves the minute structural details in wonderful perfection#ic4 ,dr ,thomas in an account of the amber beds of ,east ,prussia in #ahdh1 refers to the occurrence of large fossil trees2 he writes3 8,the continuous changes to which the coast is exposed1 often bring to light enormous trunks of trees1 which the common people had long regarded as the trunks of the amber tree1 before the learned declared that they were the stems of palm trees1 and in consequence determined the position of ,paradise to be on the coast of ,east ,prussia#id40 ,sidenote3 ,,casts ,,of ,,trees4 ,in #ahhg an enormous fossil plant was discovered in a sandstone quarry at ,clayton near ,bradford#ie4 ,the fossil was in the form of a sandstone cast of a large and repeatedly branched ,stigmaria1 and it is now in the ,owens ,college ,museum1 where it was placed through the instrumentality of ,prof4 ,williamson4 ,the plant was found spread out in its natural position on the surface of an arenaceous shale1 and overlain by a bed of hard sandstone identical with the material of which the cast is composed4 ,williamson has thus described the manner of formation of the fossil3 8,it is obvious that the entire base of the tree became encased in a plastic material1 which was firmly moulded upon these roots whilst the latter retained their organisation sufficiently unaltered to enable them to resist all superincumbent pressure4 ,this external mould then hardened firmly1 and as the organic materials decayed they were floated out by water which entered the branching cavity2 at a still later period the same water was instrumental in replacing the carbonaceous elements by the sand of which the entire structure now consists#if40 ,although the branches have not been preserved for their whole length1 they extend a distance of #bi feet #f inches from right to left1 and #bh feet in the opposite direction4 ,the fossil represented in fig4 #a 7p4 #aj71 from the collection of ,dr ,john ,woodward1 affords a good example of a well-defined impression4 ,the surface of the specimen1 of which a cast is represented in fig4 #a1 shows very clearly the characteristic leaf-cushions and leaf-scars of a ,lepidodendron4 ,the stem was embedded in soft sand1 and as the latter became hard and set1 an impression was obtained of the external markings of the ,lepidodendron4 ,decay subsequently removed the substance of the plant4 ,illustration3 ,,fig4 #aa4 ,equisetites columnaris ,brongn4 ,from a specimen in the ,woodwardian ,museum1 ,cambridge4 nat4 size4 ,in fig4 #aa some upright stems of a fossil ,horse-tail 7,equisetites columnaris7 from the ,lower ,oolite rocks near ,scarborough1 are seen in a vertical position in sandstone4 ,on the surface of the fossils there is a thin film of carbonaceous matter1 which is all that remains of the original plant substance2 the stems were probably floated into their present position and embedded vertically in an arenaceous matrix4 ,the hollow pith-cavity was filled with sand1 and as the tissues decayed they became in part converted into a thin coaly layer4 ,the vertical position of such stems as those in fig4 #aa naturally suggests their preservation in situ1 but in this as in many other cases the erect manner of occurrence is due to the settling down of the drifted plants in this particular position4 ,sidenote3 ,,fossil ,,casts4 ,an example of ,stigmaria drawn in fig4 #ab further illustrates the formation of casts#ig4 ,the outer surface with the characteristic spirally arranged circular depressions1 represents the wrinkled bark of the dried plant2 the smaller cylinder1 on the left side of the upper end 7fig4 #ab1 #b1 p7 marks the position of the pith surrounded by the secondary wood1 which has been displaced from its axial position4 ,the pith decayed first1 and the space was filled in with mud2 somewhat later the wood and cortex were partially destroyed1 and the rod of material which had been introduced into the pith-cavity dropped towards one side of the decaying shell of bark4 ,illustration3 ,,fig4 #ab4 ,stigmaria ficoides ,brongn4 #a4 ,side view1 showing wrinkled surface and the scars of appendages4 #b4 ,end view 7upper7 showing the displaced central cylinder2 p1 pith1 x1 xylem1 r1 medullary rays4 #c4 ,end view 7lower74 ,from a specimen in the ,woodwardian ,museum4 nat4 size4 ,as the parenchymatous medullary rays readily decayed1 the mud in the pith extended outwards between the segments of wood which still remained intact1 and so spokes of argillaceous material were formed which filled the medullary ray cavities4 ,the cortical tissues were decomposed1 and their place taken by more argillaceous material4 ,at one end of the specimen 7fig4 #ab1 #c7 we find the wood has decayed without its place being afterwards filled up with foreign material4 ,at the opposite end of the specimen1 the woody tissue has been partially preserved by the infiltration of a solution containing carbonate of lime 7fig4 #ab1 #b74 ,numerous instances have been recorded from rocks of various geological ages of casts of stems standing erect and at right angles to the bedding of the surrounding rock4 ,these vertical trees occasionally attain a considerable length1 and have been formed by the filling in by sand or mud of a pipe left by the decay of the stem4 ,it is frequently a matter of some difficulty to decide how far such fossils are in the position of growth of the tree1 or whether they are merely casts of drifted stems1 which happen to have been deposited in an erect position4 ,the weighting of floating trees by stones held in the roots1 added to the greater density of the root wood1 has no doubt often been the cause of this vertical position4 ,in attempting to determine if an erect cast is in the original place of growth of the tree1 it is important to bear in mind the great length of time that wood is able to resist decay1 especially under water4 ,the wonderful state of preservation of old piles found in the bed of a river1 and the preservation of wooden portions of anchors of which the iron has been completely removed by disintegration1 illustrate this power of resistance4 ,in this connection1 the following passage from ,lyell's travels in ,america is of interest4 ,in describing the site of an old forest1 he writes#ih3 8,some of the stumps1 especially those of the fir tribe1 take fifty years to rot away1 though exposed in the air to alternations of rain and sunshine1 a fact on which every geologist will do well to reflect1 for it is clear that the trees of a forest submerged beneath the water1 or still more1 if entirely excluded from the air1 by becoming imbedded in sediment1 may endure for centuries without decay1 so that there may have been ample time for the slow petrifaction of erect fossil trees in the ,carboniferous and other formations1 or for the slow accumulation around them of a great succession of strata40 ,in another place1 in speaking of the trees in the ,great ,dismal ,swamp1 ,lyell writes3--8,when thrown down1 they are soon covered by water1 and keeping wet they never decompose1 except the sap wood1 which is less than an inch thick#ii40 ,we see1 then1 that trees may have resisted decay for a sufficiently long time to allow of a considerable deposition of sediment4 ,it is very difficult to make any computation of the rate of deposition of a particular set of sedimentary strata1 and1 therefore1 to estimate the length of time during which the fossil stems must have resisted decay4 ,sidenote3 ,,plants ,,and ,,coal4 ,the protective qualities of humus acids1 apart from the almost complete absence of ,bacteria#ajj from the waters of ,moor- or ,peat-land1 is a factor of great importance in the preservation of plants against decay for many thousands of years4 ,from examples of fossil stems or leaves in which the organic material has been either wholly or in part replaced by coal1 we may pass by a gradual transition to a mass of opaque coal in which no plant structure can be detected4 ,it is by no means uncommon to notice on the face of a piece of coal a distinct impression of a plant stem1 and in some cases the coal is obviously made up of a number of flattened and compressed branches or leaves of which the original tissues have been thoroughly carbonised4 ,a block of ,french coal1 represented in fig4 #ac1 consists very largely of laminated bands composed of the long parallel veined leaves of the genus ,cordaites and of the bark of ,lepidodendron1 ,sigillaria1 and other ,coal-,measure genera4 ,the long rhizomes and roots below the coal are preserved as casts in the underclay4 ,in examining thin sections of coal1 pieces of pitted tracheids or crushed spores are frequently met with as fragments of plant structures which have withstood decay more effectually than the bulk of the vegetable dbris from which the coal was formed4 ,the coaly layer on a fossil leaf is often found to be without any trace of the plant tissues1 but not infrequently such carbonised leaves1 if treated with certain reagents and examined microscopically1 are seen to retain the outlines of the epidermal cells of the leaf surface4 ,if a piece of the ,carbonaceous film detached from a fossil leaf is left for some days in a small quantity of nitric acid containing a crystal of chlorate of potash1 and1 after washing with water1 is transferred to ammonia1 transparent film often shows very clearly the outlines of the epidermal cell and the form of the stomata4 ,such treatment has been found useful in many cases as an aid to determination#aja4 ,prof4 ,zeiller informs me that he has found it particularly satisfactory in the case of cycadean leaves4 ,illustration3 ,,fig4 #ac4 ,part of a coal seam largely made up of ,cordaites leaves4 ,stigmaria and ,stigmariopsis shown in the rock 7underclay7 underlying the coal4 7,after ,grand',eury #hb ,pl4 ,i4 fig4 #c47 ,sidenote3 ,,fossils ,,in ,,half-,,relief4 ,it is sometimes possible to detach the thin lamina representing the carbonised leaf or other plant fragment from the rock on which it lies and to mount it whole on a slide4 ,good examples of plants treated in this way may be seen in the ,edinburgh and ,british ,museums1 especially ,sphenopteris fronds from the ,carboniferous oil shales of ,scotland4 ,in the excellent collection of fossil plants in ,stockholm there are still finer examples of such specimens1 obtained by ,dr ,nathorst from some of the ,triassic plants of ,southern ,sweden4 ,in a few instances the tissues of a plant have been converted into coal in such a manner as to retain the form of the individual cells1 which appear in section as a black framework in a lighter coloured matrix4 ,examples of such carbonised tissues were figured by some of the older writers1 and ,solms-,laubach has recently#ajb described sections of ,palaeozoic plants preserved in this manner4 ,the section represented in fig4 #gj is that of a ,calamite stem 7#h #ie cm47 in which the wood has been converted into carbonaceous material1 but the more delicate tissues have been almost completely destroyed4 ,the thin and irregular black line a little distance outside the ring of wood1 and forming the limit of the drawing1 probably represents the cuticle4 ,the whole section is embedded in a homogeneous matrix of calcareous rock1 in which the more resistant tissues of the plant have been left as black patches and faint lines4 ,mention should be made of a special form of preservation which has been described as fossilisation in half-relief4 ,if a stem is imbedded in sand or mud1 the matrix receives an impression of the plant surface1 and if the hollow pith-cavity is filled with the surrounding sediment1 the surface of the medullary cast will exhibit markings different from those seen on the surface in contact with the outside of the stem4 ,the space separating the pith-cast from the mould bearing the impression of the stem surface may remain empty1 or it may be filled with sedimentary material4 ,in half-relief fossils1 on the other hand1 we have projecting from the under surface of a bed a more or less rounded and prominent ridge with certain surface markings1 and fitting into a corresponding groove in the underlying rock on which the same markings have been impressed4 ,it is conceivable that such a cast might be obtained if soft plant fragments were lying on a bed of sand1 and were pressed into it by the weight of superincumbent material4 ,the plant fragment would be squeezed into a depression1 and its substance might eventually be removed and leave no other trace than the half-relief cast and hollow mould4 ,a twig lying on sand would by its own weight gradually sink a little below the surface2 if it were then blown away or in some manner removed1 the depression would show the surface features of the twig4 ,when more sand came to be spread out over the depression1 it would find its way into the pattern of the mould1 and so produce a cast4 ,if at a later period when the sand had hardened1 the upper portion were separated from the lower1 from the former there would project a rounded cast of the hollow mould4 ,the preservation of soft algae as half-relief casts has been doubted by ,nathorst#ajc and others as an unlikely occurrence in nature4 ,they prefer to regard such ridges on a rock face as the casts of the trails or burrows of animals4 ,this question of the preservation of the two sides of a mould showing the same impression of a plant has long been a difficult problem2 it is discussed by ,parkinson in his ,organic ,remains4 ,in one of the letters 7,no4 ,,xlvi471 he quotes the objection of a sceptical friend1 who refuses to believe such a manner of preservation possible1 8until10 says ,parkinson1 8,i can inform him if1 by involving a guinea in plaster of ,paris1 ,i could obtain two impressions of the king's head1 without any impression of the reverse#ajd40 ,it would occupy too much space to attempt even a brief reference to the various materials in which impressions of plants have been preserved4 ,carbonaceous matter is the most usual substance1 and in some cases it occurs in the form of graphite which on dark grey or black rocks has the appearance of a plant drawn in lead pencil4 ,the impressions of plants on the ,jurassic 7,kimeridgian7 slates of ,solenhofen#aje in ,bavaria1 like those on the ,triassic sandstones of the ,vosges1 are usually marked out in red iron oxide4 ,sidenote3 ,,petrified ,,trees4 ,so far we have chiefly considered examples of plants preserved in various ways by incrustation1 that is1 by having been enclosed in some medium which has received an impression of the surface of the plant in contact with it4 ,by far the most valuable fossil specimens from a botanical point of view are however those in which the internal structure has been preserved2 that is in which the preserving medium has not served merely as an encasing envelope or internal cast1 but has penetrated into the body of the plant fragment and rendered permanent the organization of the tissues4 ,in almost every ,natural ,history or ,geological ,museum one meets with specimens of petrified trees or polished sections of fossil palm stems and other plants1 in which the internal structure has been preserved in siliceous material1 and admits of detailed investigation in thin sections under the microscope4 ,silica1 calcium carbonate1 with usually a certain amount of carbonate of iron and magnesium carbonate1 iron pyrites1 amber1 and more rarely calcium fluoride or other substances have taken the place of the original cell-walls4 ,of silicified stems1 those from ,antigua1 ,egypt1 ,central ,france1 ,saxony1 ,brazil1 ,tasmania#ajf1 and numerous other places afford good examples4 ,darwin records numerous silicified stems in ,northern ,chili1 and the ,uspallata ,pass4 ,in the central part of the ,andes range1 #gjjj feet high1 he describes the occurrence of 8,snow-white projecting silicified columns4444 ,they must have grown10 he adds1 8in volcanic soil1 and were subsequently submerged below sea-level1 and covered with sedimentary beds and lava-flows#ajg40 ,a striking example of the occurrence of numerous petrified plant stems has been described by ,holmes from the ,tertiary forests of the ,yellowstone ,park4 ,from the face of a cliff on the north side of ,amethyst mountain 8rows of upright trunks stand out on the ledges like the columns of a ruined temple4 ,on the more gentle slopes farther down1 but where it is still too steep to support vegetation1 save a few pines1 the petrified trunks fairly cover the surface1 and were at first supposed by us to be the shattered remains of a recent forest#ajh40 ,marsh#aji and ,conwentz#aaj have described silicified trees more than fifty feet in length from a locality in ,california where several large forest trees of ,tertiary age have been preserved in volcanic strata4 ,in ,south ,africa on the ,drakenberg hills there occur numerous silicified trunks1 occasionally erect and often lying on the ground1 probably of ,triassic age#aaa4 ,in some instances the specimens measure several feet in length and diameter4 ,some of the coniferous stems seen in ,portland1 and occasionally met with reared up against a house side1 illustrate the silicification of plant structure on a large scale4 ,these are of ,upper ,jurassic 7,purbeck7 age4 ,from ,grand',croix in ,france a silicified stem of ,cordaites of ,palaeozoic age has been recorded with a length of twenty meters4 ,the preservation of plants by siliceous infiltrations has long been known4 ,one of the earliest descriptions of this form of petrifaction in the ,british ,isles is that of stems found in ,lough ,neagh1 ,ireland4 ,in his lectures on ,natural ,philosophy1 published at ,dublin in #agea1 ,barton gives several figures of ,irish silicified wood1 and records the following occurrence in illustration of the peculiar properties erroneously attributed to the waters of ,lough ,neagh4 ,describing a certain specimen 7,no4 ,,xxvi71 he writes3-- 8,this is a whetstone1 which as ,mr ,anthony ,shane1 apothecary1 who was born very near the lake1 and is now alive1 relates1 he made by putting a piece of holly in the water of the lake near his father's house1 and fixing it so as to withstand the motion of the water1 and marking the place so as to distinguish it1 he went to ,scotland to pursue his studies1 and seven years after took up a stone instead of holly1 the metamorphosis having been made in that time4 ,this account he gave under his handwriting4 ,the shore thereabouts is altogether loose sand1 and two rivers discharge themselves into the lake very near that place#aab40 ,the well-known petrified trees from the neighbourhood of ,lough ,neagh are probably of ,pliocene age1 but their exact source has been a matter of dispute#aac4 ,sidenote3 ,,petrified ,,wood4 ,in #ahcf ,stokes described certain stems in which the tissues had been partially mineralised4 ,in describing a specimen of beech from a ,roman aqueduct at ,eibsen in ,lippe ,bckeburg1 he says3-- 8,the wood is1 for the most part1 in the state of very old dry wood1 but there are several insulated portions1 in which the place of the wood has been taken by carbonate of lime4 ,these portions1 as seen on the surface of the horizontal section1 are irregularly circular1 varying in size1 but generally a little less or more than inch in diameter1 and they run through the whole thickness of the specimen in separate1 perpendicular columns4 ,the vessels of the wood are distinctly visible in the carbonate of lime1 and are more perfect in their form and size in those portions of the specimen than in that which remains unchanged#aad40 ,illustration3 ,,fig4 #ad4 ,a4 ,araucarioxylon ,withami 7,l4 and ,h474 ,radiating lines of crystallisation in secondary wood1 as seen in transverse section4 ,b4 ,lepidodendron sp4 ,concentric lines of crystallisation1 and scalariform tracheids1 as seen in longitudinal section4 ,this partial petrifaction of the structure in patches is often met with in fossil stems1 and may be seriously misleading to those unfamiliar with the appearance presented by the crystallisation of silica from scattered centres in a mass of vegetable tissue4 ,a good example of this is afforded by the gigantic stems discovered in #ahbi in the ,craigleith ,quarry near ,edinburgh#aae4 ,of those two large stems found in the ,sandstone rock1 the longest1 originally #aa meters long and #cc-ci meters in girth1 is now set up in the grounds of the ,british ,museum1 and a large polished section 7#a m4 #hg cm47 is exhibited in the ,fossil-plant ,gallery4 ,the other stem is in the ,botanic ,garden1 ,edinburgh4 ,transverse sections of the wood of the ,london specimen show scattered circular patches 7fig4 #ad ,a7 in the mineralised wood in which the tracheids are very clearly preserved2 while in the other portion the preservation is much less perfect4 ,the patch of tissue in fig4 #ad ,a shows a portion of the wood of the ,craigleith tree ,araucarioxylon ,withami 7,l4 and ,h47 in which the mineral matter1 consisting of dolomite with a little silica here and there1 has crystallised in such a manner as to produce what is practically a cone-in-cone structure on a small scale1 which has partially obliterated the structural features4 ,this minute cone-in-cone structure is not uncommon in petrified tissues2 it is precisely similar in appearance to that described by ,cole#aaf in certain minerals4 ,the crystallisation has been set up along lines radiating from different centres1 and the particles of the tissue have been pushed as it were along these lines4 ,illustration3 ,,fig4 #ae4 ,transverse section of the central cylinder of a ,carboniferous ,lepidodendroid stem in the collection of ,mr ,kidston4 ,from ,dalmeny1 ,scotland4 s4 ,silica filling up the central portion of the pith4 p4 ,remains of the pith tissue4 x4 ,primary xylem4 x4 ,secondary xylem4 c4 ,innermost cortex4 ,sidenote3 ,,preservation ,,of ,,tissues4 ,a somewhat different crystallisation phenomenon is illustrated by the extremely fine section of a ,lepidodendroid plant shown in fig4 #ae4 ,the tissues of the primary and secondary wood 7x and x7 are well preserved throughout in silica1 but scattered through the siliceous matrix there occur numerous circular patches1 as seen in the figure4 ,one of these is more clearly shown in fig4 #ad ,b drawn from a longitudinal section through the secondary wood1 x2 it will be noticed that where the concentric lines of the circular patch occur1 the scalariform thickenings of the tracheids are sharply defined1 but immediately a tracheid is free of the patch these details are lost4 ,it would appear that in this case silicification was first completed round definite isolated centres1 and the secondary crystallisation in the matrix partially obliterated some of the more delicate structural features4 ,the same phenomenon has been observed in oolitic rocks#aag1 in which the oolitic grains have resisted secondary crystallisation and so retained their original structure4 ,among the most important examples of silicified plants are those from a few localities in ,central ,france4 ,in the neighbourhood of ,autun there used to be found in abundance loose nodules of siliceous rock containing numerous fragments of seeds1 twigs1 and leaves of different plants4 ,the rock of which the broken portions are found on the surface of the ground was formed about the close of the ,carboniferous period4 ,at the hands of ,french investigators the microscopic examination of these fragments of a ,palaeozoic vegetation have thrown a flood of light on the anatomical structure of many extinct types4 ,sometimes the silica has penetrated the cavities of the cells and vessels1 and the walls have decayed without their substance being replaced by mineral material4 ,sections of tissues preserved in this manner1 if soaked in a coloured solution assume an appearance almost identical with that of stained sections of recent plants4 ,the spaces left by the decayed walls act as fine capillaries and suck up the coloured solution#aah4 ,illustration3 ,,fig4 #af4 ,internal cast of a sclerenchymatous cell from the root of a ,cretaceous fern 7,rhizodendron oppoliense ,gpp474 ,after ,stenzel 7#hf7 ,pl4 ,,iii4 fig4 #bi4 #bdj and reduced to one-half4 ,in the ,coal-,measure sandstones of ,england large pieces of woody stems are occasionally met with in which the mineralisation has been incomplete4 ,a brown piece of fossil stem lying in a bed of sandstone shows on the surface a distinct woody texture1 and the lines of wood elements are clearly visible4 ,the whole is1 however1 very friable and falls to pieces if an attempt is made to cut thin sections of it2 the tracheids of the wood easily fall apart owing to the walls being imperfectly preserved1 and the absence of a connecting framework such as would have been formed had the membranes been thoroughly silicified4 ,it is occasionally possible to obtain from petrified plant stems perfect casts in silica or other substances of the cavity of a sclerenchymatous fibre1 in which the mineral has been deposited not only in the cavity but in the fine pit-canals traversing the lignified walls4 ,such a cast is represented in fig4 #af1 the fine lateral projections are the delicate casts of the pit canals4 ,numerous instances of minute and delicate tissues preserved in silica are recorded in later chapters4 ,a somewhat unusual type of silicification is met with in some of the ,gondwana rocks of ,india1 in which cycadean fronds occur as white porcellaneous specimens showing a certain amount of internal structure in a siliceous matrix4 ,specimens of such leaves may be seen in the ,british ,museum4 ,sidenote3 ,,coal-,,balls4 ,in the ,coal-,measures of ,england1 especially in the neighbourhood of ,halifax in ,yorkshire1 and in ,south ,lancashire1 the seams of coal occasionally contain calcareous nodules varying in size from a nut to a man's head1 and consisting of about #gj of carbonate of calcium and magnesium1 and #cj of oxide of iron1 sulphide of iron1 c4#aai ,the nodules1 often spoken of by ,english writers as #8coal-balls1' contain numerous fragments of plants in which the minute cellular structure is preserved with remarkable perfection4 ,it should be noted that the term coal-ball is also applied to rounded or subangular pieces of coal which are occasionally met with in coal seams1 and especially in certain ,french coal fields4 ,to avoid confusion it is better to speak of the plant-containing nodules as calcareous nodules1 restricting the term coal-ball to true coal pebbles4 ,a section of a calcareous nodule1 when seen under the microscope1 presents the appearance of a matrix of a crystalline calcareous substance containing a heterogeneous mixture of all kinds of plant tissues1 usually in the form of broken pieces and in a confused mass4 ,illustration3 ,,fig4 #ag4 ,a thin section of a calcareous nodule from the ,coal-,measures4 ,binney collection1 ,woodwardian ,museum1 ,cambridge4 ,very slightly reduced4 ,a large section of one of these nodules 7#abe cm4 #he cm47 is shown in fig4 #ag4 ,it illustrates the manner of occurrence of various fragments of different plants in which the structure has been more or less perfectly preserved4 ,in this particular example we see sections of ,myeloxylon 7,i71 ,calamites 7,,ii71 ,fern petioles 7,rachiopteris7 7,,iii71 ,stigmarian appendages 7,,iv71 ,lepidodendroid leaves 7,v71 ,myeloxylon pinnules 7,,vi71 ,gymnospermous seeds 7,,vii71 ,twig of a ,lepidodendron1 showing the central xylem cylinder and large leaf-bases on the outer cortex1 7,,viii71 ,sporangia and spores of a strobilus 7,,ix71 ,tangential section of a ,myeloxylon petiole 7,x71 ,rachiopteris sp4 7,,xi71 ,rachiopteris sp4 7,,xii71 ,band of sclerenchymatous tissue 7,,xiii71 ,rachiopteris sp4 7,,xiv74 ,the general appearance of a calcareous plant-nodule suggests a soft pulpy mass of decaying vegetable dbris1 through which roots were able to bore their way1 as in a piece of peat or leafy mould4 ,overlying this accumulation of soft material there was spread out a bed of muddy sediment containing numerous calcareous shells1 which supplied the percolating water with the material which was afterwards deposited in portions of the vegetable dbris4 ,according to this view the calcareous nodules of the coal seams represent local patches of a widespread mass of dbris which were penetrated by a carbonated solution1 and so preserved as samples of a decaying mass of vegetation1 of which by far the greater portion became eventually converted into coal#abj4 ,sidenote3 ,,fossil ,,nuclei4 ,in such nodules1 we find that not only has the framework of the tissues been preserved1 but frequently the remains of cell contents are clearly seen4 ,in some cases the cells of a tissue may contain in each cavity a darker coloured spot1 which is probably the mineralised cell nucleus4 7,fig4 #db1 ,a1 #a1 p4 #bad47 ,the contents of secretory sacs1 such as those containing gum or resin1 are frequently found as black rods filling up the cavity of the cell or canal4 ,the contents of cells in some cases closely simulate starch grains1 and such may have been actually present in the tissues of a piece of a fossil dicotyledonous stem described by ,thiselton-,dyer from the ,lower ,eocene ,thanet beds#aba1 and in the rhizome of a fossil ,osmunda recorded by ,carruthers#abb4 7,fig4 #db1 ,b1 p4 #bad47 ,schultze in #aheeabc recorded the discovery of cellulose by microchemical tests applied to macerated tissue from ,tertiary lignite and coal4 ,with reference to the possibility of recognising cell contents in fossil tissue it is interesting to find that ,dr ,murray of ,scarborough had attempted1 and apparently with success1 to apply chemical tests to the tissues of ,jurassic leaves4 ,in a letter written to ,hutton in #ahcc ,murray speaks of his experiments as follows3-- 8,reverting to the ,oolitic plants1 ,i have again and with better success been experimenting upon the thin transparent films of leaves1 chiefly of ,taeniopteris vittata and ,cyclopteris1 which from their tenuity offer fine objects for the microscope4444 ,by many delicate trials ,i have ascertained the existence still in these leaves of resin and of tannin4444 ,i am seeking among the filmy leaves of the ,fucoides of ,a4 ,brongniart for iodine1 but hitherto without success1 and indeed can hardly expect it1 as probably did iodine exist in them1 it must have long ago entered into new combinations#abd40 ,apart from this difficulty1 it is not surprising that ,dr ,murray's search for iodine was unsuccessful1 considering how little algal nature most of the so-called ,fucoids possess4 ,some of the most perfectly preserved tissues as regards the details of cell contents are those of gymnospermous seeds from ,autun4 ,in sections of one of these seeds which ,i recently had the opportunity of examining in ,prof4 ,bertrand's collection1 the parenchymatous cells contained very distinct nuclei and protoplasmic contents4 ,in one portion of the tissue in the nucellus of ,sphaerospermum the cell walls had disappeared1 but the nuclei remained in a remarkable state of preservation4 ,the cells shown in fig4 #db are from the ground tissue of a petiole of ,cycadeoidea gigantea ,sew4#abe1 a magnificent ,cycadean stem from ,portland recently added to the ,british ,museum collection2 in the cell ,a1 #a1 the nucleus is fairly distinct and in #b and #d the contracted cell-contents is clearly seen4 ,other interesting examples of fossil nuclei are seen in a ,lyginodendron leaf figured by ,williamson and ,scott in a recent ,memoir on that genus#abf4 ,each mesophyll cell contains a single dark nucleus4 ,the mineralisation of the most delicate tissues and the preservation of the various forms of cell-contents are now generally admitted by those at all conversant with the possibilities of plant petrifaction4 ,if we consider what these facts mean--the microscopic investigation of not only the finest framework but even the very life-substance of ,palaeozoic plants--we feel that the aeons since the days when these plants lived have been well-nigh obliterated4 ,occasionally the plant tissues have assumed a black and somewhat ragged appearance1 giving the impression of charred wood4 ,a section of a recent burnt piece of wood resembles very closely some of the fossil twigs from the coal seam nodules4 ,it is possible that in such cases we have portions of mineralised tissues which were first burnt in a forest fire or by lightning and then infiltrated with a petrifying solution4 ,an example of one of these black petrified plants is shown in fig4 #gd ,b4 ,chap4 ,x4 ,in many of the fossil plants there are distinct traces of fungus or bacterial ravages1 and occasionally the section of a piece of mineralised wood shows circular spaces or canals which have the appearance of being the work of some wood-eating animal1 and small oval bodies sometimes occur in such spaces which may be the coprolites of the xylophagous intruder4 7,fig4 #bd1 p4 #ajg47 ,sidenote3 ,,fossil ,,plants ,,in ,,volcanic ,,ash4 ,it is well known to geologists that during the ,permian and ,carboniferous periods the southern portion of ,scotland was the scene of widespread volcanic activity4 ,forests were overwhelmed by lava-streams or showers of ash1 and in some districts tree stems and broken plant fragments became sealed up in a volcanic matrix4 ,laggan ,bay in the north-east corner of the ,isle of ,arran1 and ,pettycur a short distance from ,burntisland on the north shore of the ,firth of ,forth1 are two localities where petrified plants of ,carboniferous age occur in such preservation as allows of a minute investigation of their internal structure4 ,the occurrence of plants in the former locality was first discovered by ,mr ,wnsch of ,glasgow2 the fossils occur in association with hardened shales and beds of ash1 and are often exceedingly well preserved#abg4 ,in fig4 #ah is reproduced a sketch of a hollow tree trunk from ,arran1 probably a ,lepidodendron stem1 in which only the outer portion of the bark has been preserved1 while the inner cortical tissues have been removed and the space occupied by volcanic detritus4 ,illustration3 ,,fig4 #ah4 ,diagrammatic sketch of a slab cut from a fossil stem 7,lepidodendron87 from ,laggan ,bay4 e1 ,imperfectly preserved bark of a large stem1 extending in patches round the periphery of the specimen2 the oval and circular bodies in the interior are the xylem portions of the central cylinders of ,lepidodendron stems1 x1 primary wood1 x1 secondary wood4 ,from a specimen in the ,binney collection1 ,woodwardian ,museum1 ,cambridge4 nat4 size4 ,the smaller cylindrical structures in the interior of the hollow trunk are the central woody cylinders of ,lepidodendroid trees2 each consists of an axial pith surrounded by a band of primary wood and a broader zone of secondary wood4 ,one of the axes probably belonged to the stem of which only the shell has been preserved1 the others must have come from other trees and may have been floated in by water#abh4 ,the microscopic details of the wood and outer cortex have in this instance been preserved in a calcareous material1 which was no doubt derived by water percolating through the volcanic ash4 ,it is frequently found that in fossil trees or twigs a separation of the tissues has taken place along such natural lines of weakness as the cambium or the phellogen1 before the petrifying medium had time to permeate the entire structure4 ,tree stems recently killed by lava streams during volcanic eruptions at the present day supply a parallel with the ,palaeozoic forest trees of ,carboniferous times4 ,guillemard in describing a volcanic crater in ,celebes1 speaks of burnt trees still standing in the lava stream1 8so charred at the base of the trunk that we could easily push them down#abi40 ,an interesting case is quoted by ,hooker in his ,himalayan ,journals1 illustrating the occurrence of a hollow shell of a tree1 in which the outer portions of a stem had been left while the inner portions had disappeared1 the wood being hollow and so favourable to the production of a current of air which accelerated the destruction of the internal tissues4 ,on the coast near ,burntisland on the ,firth of ,forth blocks of rock are met with in which numerous plant fragments of ,carboniferous age are scattered in a confused mass through a calcareous volcanic matrix4 ,the twigs1 leaves1 spores1 and other portions are in small fragments1 and their delicate cells are often preserved in wonderful perfection4 ,sidenote3 ,,conditions ,,of ,,preservation4 ,the manner of occurrence of plants in sandstones1 shales or other rocks is often of considerable importance to the botanist and geologist1 as an aid to the correct interpretation of the actual conditions which obtained at the time when the plant remains were accumulating in beds of sediment4 ,to attempt to restore the conditions under which any set of plants became preserved1 we have to carefully consider each special case4 ,a nest of seeds preserved as internal casts in a mass of sandstone1 such as is represented by the block of ,carboniferous sandstone in fig4 #ai1 suggests a quiet spot in an eddy where seeds were deposited in the sandy sediment4 ,delicate leaf structures with sporangia still intact1 point to quietly flowing water and a transport of no great distance4 ,occasionally the large number of delicate and light plant fragments1 associated it may be with insect wings1 may favour the idea of a wind storm which swept along the lighter pieces from a forest-clad slope and deposited them in the water of a lake4 ,in some ,tertiary plant-beds the manner of occurrence of leaves and flowers is such as to suggest a seasonal alternation1 and the different layers of plant dbris may be correlated with definite seasons of growth#acj4 ,illustration3 ,,fig4 #ai4 ,piece of ,coal-,measures ,sandstone with casts of ,trigonocarpon seeds1 from ,peel ,quarry near ,wigan4 ,from a specimen in the ,manchester ,museum1 ,owens ,college4 nat4 size4 ,the predominance of certain classes of plants in a particular bed may be due to purely mechanical causes and to differential sorting by water1 or it may be that the district traversed by the stream which carried down the fragments was occupied almost exclusively by one set of plants4 ,the trees from higher ground may be deposited in a different part of a river's course to those growing in the plains or lowland marshes4 ,it is obviously impossible to lay down any definite rules as to the reading of plant records1 as aids to the elucidation of past physical and botanical conditions4 ,each case must be separately considered1 and the various probabilities taken into account1 judging by reference to the analogy of present day conditions4 ,various attempts1 more or less successful1 have been made to imitate the natural processes of plant mineralisation#aca4 ,by soaking sections of wood for some time in different solutions1 and then exposing them to heat1 the organic substance of the cell walls has been replaced by a deposit of oxide of iron and other substances4 ,fern leaves heated to redness between pieces of shale have been reduced to a condition very similar to that of fossil fronds4 ,pieces of wood left for centuries in disused mines have been found in a state closely resembling lignite#acb4 ,attempts have also been made to reproduce the conditions under which vegetable tissues were converted into coal1 but as yet these have not yielded results of much scientific value4 ,the ,geysers of ,yellowstone ,park have thrown some light on the manner in which wood may be petrified by the percolation of siliceous solutions2 and it has been suggested that the silicification of plants may have been effected by the waters of hot springs holding silica in solution4 ,examples of wood in process of petrifaction in the ,geyser district of ,north ,america have been recorded by ,kuntze#acc1 and discussed by ,schweinfurth#acd1 ,solms-,laubach#ace and others#acf4 ,the latter expresses the opinion that by a long continuance of such action as may now be observed in the neighbourhood of hot springs1 the organic substance of wood might be replaced by siliceous material4 ,the exact manner of replacement needs more thorough investigation4 ,kuntze describes the appearance of forest trees which have been reached by the waters of neighbouring ,geysers4 ,the siliceous solution rises in the wood by capillarity2 the leaves1 branches and bark are gradually lost1 and the outer tissues of the wood become hardened and petrified as the result of evaporation from the exposed surface of the stem4 ,the products of decay going on in the plant tissues must be taken into account1 and the double decomposition which might result4 ,there is no apparent reason why experiments undertaken with pieces of recent wood exposed to permeation by various calcareous and siliceous solutions under different conditions should not furnish useful results4 ,,chapter ,v4 ,,difficulties ,,and ,,sources ,,of ,,error ,,in ,,the ,,determination ,,of ,,fossil ,,plants4 8,robinson ,crusoe did not feel bound to conclude1 from the single human footprint which he saw in the sand1 that the maker of the impression had only one leg40 ,,huxley',s ,hume1 p4 #aje1 #ahgi4 ,the student of palaeobotany has perhaps to face more than his due share of difficulties and fruitful sources of error2 but on the other hand there is the compensating advantage that trustworthy conclusions arrived at possess a special value4 ,while always on the alert for rational explanations of obscure phenomena by means of the analogy supplied by existing causes1 and ready to draw from a wide knowledge of recent botany1 in the interpretation of problems furnished by fossil plants1 the palaeobotanist must be constantly alive to the necessity for cautious statement4 ,that there is the greatest need of moderation and safe reasoning in dealing with the botanical problems of past ages1 will be apparent to anyone possessing but a superficial acquaintance with fossil plant literature4 ,the necessity for a botanical and geological training has already been referred to in a previous chapter4 ,it would serve no useful purpose1 and would occupy no inconsiderable space1 to refer at length to the numerous mistakes which have been committed by experienced writers on the subject of fossil plants4 ,laymen might find in such a list of blunders a mere comedy of errors1 but the palaeobotanist must see in them serious warnings against dogmatic conclusions or expressions of opinion on imperfect data and insufficient evidence4 ,the description of a fragment of a handle of a ,wedgwood teapot as a curious form of ,calamite#acg and similar instances of unusual determinations need not detain us as examples of instructive errors4 ,the late ,prof4 ,williamson has on more than one occasion expressed himself in no undecided manner as to the futility of attempting to determine specific forms among fossil plants1 without the aid of internal structure#ach2 and even in the case of well-preserved petrifactions he always refused to commit himself to definite specific diagnoses4 ,in his remarks in this connection1 ,williamson no doubt allowed himself to express a much needed warning in too sweeping language4 ,it is one of the most serious drawbacks in palaeobotanical researches that in the majority of cases the specimens of plants are both fragmentary and without any trace of internal structure4 ,specimens in which the anatomical characters have been preserved necessarily possess far greater value from the botanist's point of view than those in which no such petrifaction has occurred4 ,on the other hand1 however1 it is perfectly possible with due care to obtain trustworthy and valuable results from the examination of structureless casts and impressions4 ,in dealing with the less promising forms of plant fossils1 there is in the first place the danger of trusting to superficial resemblance4 ,hundreds of fossil plants have been described under the names of existing genera on the strength of a supposed agreement in external form2 but such determinations are very frequently not only valueless but dangerously misleading4 ,unless the evidence is of the best1 it is a serious mistake to make use of recent generic designations4 ,if we consider the difficulties which would attend an attempt to determine the leaves1 fragments of stems and other detached portions of various recent genera1 we can better appreciate the greater probability of error in the case of imperfectly preserved fossil fragments4 ,sidenote3 ,,external ,,resemblance4 ,the portions of stems represented in figures #bj and #ba1 exhibit a fairly close resemblance to one another2 in the absence of microscopical sections or of the reproductive organs it would be practically impossible to discriminate with any certainty between fossil specimens of the plants shown in the drawings4 ,examples such as these1 and many others which might be cited1 serve to illustrate the possibility of confusion not merely between different genera of the same family1 but even between members of different classes or groups4 ,the long slender branches of the ,polygonum represented in 7fig4 #ba7 would naturally be referred to ,equisetum in the absence of the flowers 7fig4 #bj ,b71 or without a careful examination of the insignificant scaly leaves borne at the nodes4 ,the resemblance between ,casuarina and ,ephedra and the ,british species of ,equisetum1 or such a tropical form as ,e4 debile1 speaks for itself4 ,illustration3 ,,fig4 #bj4 ,a4 ,restio tetraphylla ,labill4 7,monocotyledon74 ,b4 ,equisetum variegatum ,schleich4 7,vascular ,cryptogam74 ,c4 ,equisetum debile ,roxb4 ,d4 ,casuarina stricta ,dryand4 7,dicotyledon74 ,e4 ,ephedra distachya ,linn4 7,gymnosperm74 7,a-,e nat4 size74 ,illustration3 ,,fig4 #ba4 ,polygonum ,equisetiforme ,sibth4 and ,sm4 ,a4 ,showing habit of plant4 nat4 size4 ,the two flowers towards the apex of one branch1 drawn to a larger scale in ,b4 ,c4 ,node with small leaf and ochrea characteristic of ,polygonace4 ,from a plant in the ,cambridge ,botanic ,garden4 ,illustration3 ,,fig4 #bb4 ,kaulfussia sculifolia ,blume4 ,from a specimen from ,java in the ,british ,museum herbarium4 nat4 size4 ,endless examples might be quoted illustrating the absolute futility1 in many cases1 of relying on external features even for the purpose of class distinction4 ,an acquaintance with the general habit and appearance of only the better known members of a family1 frequently leads to serious mistakes4 ,the specimen shown in fig4 #bb is a leaf of a tropical fern ,kaulfussia1 a genus now living in ,south-eastern ,asia1 and a member of one of the most important and interesting families of the ,filicin1 the ,marrattiace2 its form is widely different from that which one is accustomed to associate with fern fronds4 ,it is unlikely that the impression of a sterile leaf of ,kaulfussia would be recognised as a portion of a fern plant4 ,similarly in another exceedingly important group of plants1 the ,cycadace#aci1 the examples usually met with in botanical gardens are quite insufficient as standards of comparison when we are dealing with fossil forms4 ,familiarity with a few commoner types leads us to regard them as typical for the whole family4 ,in ,mesozoic times cycadean plants were far more numerous and widely distributed than at the present time1 and to adequately study the numerous fossil examples we need as thorough an acquaintance as possible with the comparatively small number of surviving genera and species4 ,the less common and more isolated species of an existing family may often be of far greater importance to the palaeobotanist than the common and more typical forms4 ,this importance of rare and little known types will be more fully illustrated in the chapters dealing with the ,cycadace and other plant groups4 ,among ,dicotyledons1 the ,natural ,order ,proteace1 at present characteristic of ,south ,africa and ,australia1 and also represented in ,south ,america and the ,pacific ,islands1 is of considerable interest to the student of fossil ,angiosperms4 ,in a valuable address delivered before the ,linnean ,society#adj in #ahgj ,bentham drew attention to the marked #8protean' character of the members of this family4 ,he laid special stress on this particular division of the ,dicotyledons in view of certain far-reaching conclusions1 which had been based on the occurrence in different parts of ,europe of fossil leaves supposed to be those of ,proteaceous genera#ada4 ,speaking of detached leaves1 ,bentham says3--8,i do not know of a single one which1 in outline or venation1 is exclusively characteristic of the order1 or of any one of its genera40 ,species of ,grevillea1 ,hakea and a few other genera are more or less familiar in plant houses1 but the leaf-forms illustrated by the commoner members of the family convey no idea of the enormous variation which is met with not only in the family as a whole1 but in the different species of the same genus4 ,the striking diversity of leaf within the limits of a single genus will be dealt with more fully in volume ,,ii4 under the head of ,fossil ,dicotyledons4 ,sidenote3 ,,venation ,,characters4 ,there is a common source of danger in attempting to carry too far the venation characters as tests of affinity4 ,the parallel venation of ,monocotyledons is by no means a safe guide to follow in all cases as a distinguishing feature of this class of plants4 ,in addition to such leaves as those of the ,gymnosperm ,cordaites and detached pinn of ,cycads1 there are certain species of ,dicotyledons which correspond in the character of their venation to ,monocotyledonous leaves4 ,eryngium montanum ,coult41 ,e4 ,lassauxi ,dcne41 and other species of this genus of ,umbellifer agree closely with such a plant as ,pandanus or other ,monocotyledons2 similarly the long linear leaves of ,richea dracophylla1 ,r4 ,br41 one of the ,ericace1 are identical in form with many monocotyledonous leaves4 ,instances might also be quoted of monocotyledonous leaves1 such as species of ,smilax and others which ,lindley included in his family of ,dictyogens which correspond closely with some types of ,dicotyledons#adb4 ,venation characters must be used with care even in determining classes or groups1 and with still greater reserve if relied on as family or generic tests4 ,it is too frequently the case that while we are conversant with the most detailed histological structure of a fossil plant stem1 its external form is a matter of conjecture4 ,the conditions which have favoured the petrifaction of plant tissues have as a rule not been favourable for the preservation of good casts or impressions of the external features2 and1 on the other hand1 in the best impressions of fern fronds or other plants1 in which the finest veins are clearly marked1 there is no trace of internal structure4 ,it is1 however1 frequently the case that a knowledge of the internal structure of a particular plant enables us to interpret certain features in a structureless cast which could not be understood without the help of histological facts4 ,a particularly interesting example of anatomical knowledge affording a key to apparently abnormal peculiarities in a specimen preserved by incrustation1 is afforded by the fructification of the genus ,sphenophyllum4 ,some few years ago ,williamson described in detail the structure of a fossil strobilus 7i4e4 cone7 from the ,coal-,measures1 but owing to the isolated occurrence of the specimens he was unable to determine the plant to which the strobilus belonged4 ,on re-examining some strobili of ,sphenophyllum1 preserved by incrustation1 in the light of ,williamson's descriptions1 ,zeiller was able to explain certain features in his specimens which had hitherto been a puzzle1 and he demonstrated that ,williamson's cone was that of a ,sphenophyllum4 ,similar examples might be quoted1 but enough has been said to emphasize the importance of dealing as far as possible with both petrifactions and incrustations4 ,the facts derived from a study of a plant in one form of preservation may enable us to interpret or to amplify the data afforded by specimens preserved in another form4 ,sidenote3 ,,decorticated ,,stems4 ,the fact that plants usually occur in detached fragments1 and that they have often been sorted by water1 and that portions of the same plant have been embedded in sediment considerable distances apart1 is a constant source of difficulty4 ,deciduous leaves1 cones1 or angiospermous flowers1 and other portions of a plant which become naturally separated from the parent tree1 are met with as detached specimens1 and it is comparatively seldom that we have the necessary data for reuniting the isolated members4 ,as the result of the partial decay and separation of portions of the same stem or branch1 the wood and bark may be separately preserved4 ,darwin#adc describes how the bark often falls from ,eucalyptus trees1 and hangs in long shreds1 which swing about in the wind1 and give to the woods a desolate and untidy appearance4 ,in the passage already quoted from the narrative of the voyage of the ,challenger1 illustrations are afforded of the manner in which detached portions of plants are likely to be preserved in a fossil state4 ,the epidermal layer of a leaf or the surface tissues of a twig may be detached from the underlying tissues and separately preserved#add4 ,it is exceedingly common for a stem to be partially decorticated before preservation1 and the appearance presented by a cast or impression of the surface of a woody cylinder1 and by the same stem with a part or the whole of its cortex intact is strikingly different4 ,the late ,prof4 ,balfour#ade draws attention to this source of error in his text-book of palaeobotany1 and gives figures illustrating the different appearance presented by a branch of ,araucaria imbricata ,pav4 when seen with its bark intact and more or less decorticated4 ,specimens that are now recognised as casts of stems from which the cortex had been more or less completely removed before preservation1 were originally described under distinct generic names1 such as ,bergeria1 ,knorria and others4 ,these are now known to be imperfect examples of ,sigillarian or ,lepidodendroid plants4 ,grand',eury#adf quotes the bark of ,lepidodendron ,veltheimianum ,presl4 as a fossil which has been described under twenty-eight specific names1 and placed in several genera4 ,since the microscopical examination of fossil plant-anatomy was rendered possible1 a more correct interpretation of decorticated and incomplete specimens has been considerably facilitated4 ,the examination of tangential sections taken at different levels in the cortex of such a plant as ,lepidodendron brings out the distribution of thin and thick-walled tissue4 ,regularly placed prominences on such a stem as the ,knorria shown in fig4 #bc are due to the existence in the original stem of spirally disposed areas of thin-walled and less resistant tissue2 as decay proceeded1 the thinner cells would be the first to disappear1 and depressions would thus be formed in the surrounding thicker walled and stronger tissue4 ,if the stem became embedded in mud or sand before the more resistant tissue had time to decay1 but after the removal of the thin-walled cells1 the surrounding sediment would fill up the depressions and finally1 after the complete decay of the stem1 the impression on the mould or on the cast1 formed by the filling up of the space left by the stem1 would have the form of regularly disposed projections marking the position of the more delicate tissues4 ,the specimen represented in the figure is an exceedingly interesting and well preserved example of a ,coal-,measure stem combining in itself representatives of what were formerly spoken of as distinct genera4 ,illustration3 ,,fig4 #bc4 ,a dichotomously branched ,lepidodendroid stem 7,knorria mirabilis ,ren4 and ,zeill474 ,after ,renault and ,zeiller#adg4 7 nat4 size47 ,the original specimen is in the ,natural ,history ,museum1 ,paris4 ,the surface of the fossil as seen at e affords a typical example of the ,knorria type of stem2 the spirally disposed peg-like projections are the casts of cavities formed by the decay of the delicate cells surrounding each leaf-trace bundle on its way through the cortex of the stem4 ,the surface g exhibits a somewhat different appearance1 owing to the fact that we have the cast of the stem taken at a slightly different level4 ,the surface of the thick layer of coal at a shows very clearly the outlines of the leaf-cushions2 on the somewhat deeper surfaces b1 c and d the leaf-cushions are but faintly indicated1 and the long narrow lines on the coal at c represent the leaf-traces in the immediate neighbourhood of the leaf-cushions4 ,sidenote3 ,,imperfect ,,casts4 ,it is not uncommon among the older plant-bearing rocks to find a piece of sandstone or shale of which the surface exhibits a somewhat irregular reticulate pattern1 the long and oval meshes having the form of slightly raised bosses4 ,the size of such a reticulum may vary from one in which the pattern is barely visible to the unaided eye to one with meshes more than an inch in length4 ,the generic name ,lyginodendron#adh was proposed several years ago 7#ahdc7 for a specimen having such a pattern on its surface1 but without any clue having been found as to the meaning of the elongated raised areas separated from one another by a narrow groove4 ,at a later date ,williamson investigated the anatomy of some petrified fragments of a ,carboniferous plant which suggested a possible explanation of the surface features in the structureless specimens4 ,the name ,lyginodendron was applied to this newly discovered plant1 of which one characteristic was found to be the occurrence of a hypodermal band of strong thick-walled tissue arranged in the form of a network with the meshes occupied by thin-walled parenchyma4 ,if such a stem were undergoing gradual decay1 the more delicate tissue of the meshes would be destroyed first and the harder framework left4 ,a cast of such a partially decayed stem would take the form1 therefore1 of projecting areas1 corresponding to the hollowed out areas of decayed tissue1 and intervening depressions corresponding to the projecting framework of the more resistant fibrous tissue4 ,a precisely similar arrangement of hypodermal strengthening tissue occurs in various ,palaeozoic and other plants1 and casts presenting a corresponding appearance cannot be referred with certainty to one special genus2 such casts are of no real scientific value#adi4 ,the old generic terms ,artisia and ,sternbergia illustrate another source of error which can be avoided only by means of a knowledge of internal structure4 ,the former name was proposed by ,sternberg and the latter by ,artis for precisely similar ,carboniferous fossils1 having the form of cylindrical bodies marked by numerous transverse annular ridges and grooves4 ,these fossils are now known to be casts of the large discoid pith of the genus ,cordaites1 an extinct type of ,palaeozoic ,gymnosperms4 ,calamites and ,tylodendron afford other instances of plants in which the supposed surface characters have been shown to be those of the pith-cast4 ,the former genus is described at length in a later chapter1 but the latter may be briefly referred to4 ,a cast1 apparently of a stem1 from the ,permian rocks of ,russia was figured in #ahgj under the name ,tylodendron2 the surface being characterised by spirally arranged lozenge-shaped projections1 described as leaf-scars4 ,specimens were eventually discovered in which the supposed stem was shown to be a cast of the large pith of a plant possessing secondary wood very like that of the recent genus ,araucaria4 ,the projecting portions1 instead of being leaf-cushions1 were found to be the casts of depressions in the inner face of the wood where strands of vascular tissue bent outwards on their way to the leaves4 ,if a cast is made of the comparatively large pith of ,araucaria imbricata the features of ,tylodendron are fairly closely reproduced#aej4 ,a dried ,bracken frond lying on the ground in the ,autumn presents a very different appearance as regards the form of the ultimate segments of the frond to that of a freshly cut leaf4 ,in the former the edges of the pinnules are strongly recurved1 and their shape is considerably altered4 ,immersed in water for some time fern fronds or other leaves undergo maceration1 and the more delicate lamina of the leaf rots away much more rapidly than the scaffolding of veins4 ,among fossil fern fronds differences in the form of the pinnules and in the shape and extent of the lamina1 to which a specific value is assigned1 are no doubt in many cases merely the expression either of differences in the state of the leaves at the time of fossilisation or of the different conditions under which they became embedded4 ,differential decay and disorganisation of plant tissues are factors of considerable importance with regard to the fossilisation of plants4 ,as ,lindley#aea and later writers have suggested1 the absence or comparative scarcity of certain forms of plants from a particular fossil flora may in some cases be due to their rapid decay and non-preservation as fossils2 it does not necessarily mean that such plants were unrepresented in the vegetation of that period4 ,the decayed rhizomes of the ,bracken fern often seen hanging from the roadside banks on a heath or moorland1 and consisting of flat dark coloured bands of resistant sclerenchyma in a loose sheath of the hard shrivelled tissue1 are in striking contrast to the perfect stem4 ,a rotting ,palm stem is gradually reduced to a loose stringy mass consisting of vascular strands of which the connecting parenchymatous tissue has been entirely removed4 ,it must frequently have happened that detached vascular bundles or strands and plates of hard strengthening tissue have been preserved as fossils and mistaken for complete portions of plants4 ,sidenote3 ,,mineral ,,deposits ,,simulating ,,plants4 ,apart from the necessity of keeping in view the possible differences in form due to the state of the plant fragments at the time of preservation1 and the marked contrast between the same species preserved in different kinds of rock1 there are numerous sources of error which belong to an entirely different category4 ,the so-called moss-agates and the well-known dendritic markings of black oxide of manganese1 are among the better known instances of purely inorganic structures simulating plant forms4 ,an interesting example of this striking similarity between a purely mineral deposit and the external form of a plant is afforded by some specimens originally described as impressions of the oldest known fern4 ,the frontispiece to a well-known work on fossil plants1 ,le monde des plantes avant l'apparition de l'homme#aeb1 represents a fern-like fossil on the surface of a piece of ,silurian slate4 ,the supposed plant was named ,eopteris ,morierei ,sap41 and it is occasionally referred to as the oldest land plant in books of comparatively recent date4 ,in the ,museum of the ,school of ,mines1 ,berlin1 there are some specimens of ,angers slate on some of which the cleavage face shows a shallow longitudinal groove bearing on either side somewhat irregularly oblong and oval appendages of which the surface is traversed by fine vein-like markings4 ,a careful examination of the slate reveals the fact that these apparent fern pinnules are merely films of iron pyrites deposited from a solution which was introduced along the rachis-like channel4 ,many of the extraordinary structures described as plants by ,reinsch#aec in his ,memoir on the minute structure of coal have been shown to be of purely mineral origin4 ,the innumerable casts of animal-burrows and trails as well as the casts of egg-cases and various other bodies1 which have been described as fossil algae1 must be included among the most fruitful sources of error4 ,it requires but a short experience of microscopical investigation of fossil plant structures to discover numerous pitfalls in the appearance presented by sections of calcareous and siliceous nodules4 ,the juxtaposition of tissues apparently parts of the same plant1 and the penetration by growing roots of partially decayed plant dbris1 serve to mislead an unpractised observer4 ,in sections of the ,english #8calcareous nodules' one very frequently finds the tissue of ,stigmarian appendages occupying every conceivable position1 and preserved in places admirably calculated to lead to false interpretations4 ,the more minute investigation of tissues is often rendered difficult by deceptive appearances simulating original structures1 but which are in reality the result of mineralisation4 ,it is no easy matter in some cases to discover whether a particular cell in a fossil tissue was originally thick-walled1 or whether its sclerous appearance is due to the deposition of mineral matter on the inside of the thin cell-membrane4 ,examples of such sources of error as have been briefly referred to1 and others1 will be found in various parts of the descriptive portions of this book4 ,illustration3 ,,fig4 #bd4 ,a4 ,section of partially disorganised tissue attacked by some boring animal4 c1 c1 coprolites2 d1 a tunnel made by the borer through the plant tissue4 ,b4 ,transverse section of a ,lepidodendroid leaf1 of which the inner tissues have been destroyed and the cavity filled with coprolites2 simulating a sporangium containing spores4 7,a and ,b from specimens in the ,botanical ,laboratory collection1 ,cambridge47 ,sidenote3 ,,traces ,,of ,,wood-,,borers ,,in ,,petrified ,,tissue4 ,there is one other form of pitfall which should be briefly noticed4 ,in sections of petrified plants one occasionally finds clean cut canals penetrating a mass of tissue1 and differing in their manner of occurrence and in their somewhat larger size from ordinary secretory ducts4 ,such tunnels or canals are probably the work of a wood-boring animal4 ,an example is illustrated in fig4 #bd ,a4 ,similarly it is not unusual to meet with groups or nests of spherical or elliptical bodies lying among plant tissues1 and having the appearance of spores4 ,such spore-like bodies appear on close examination to be made up of finely comminuted particles of tissue1 and in all probability they are the coprolites of some xylophagous animal4 ,examples of such coprolites are shown in fig4 #bd ,a#aed1 and in fig4 #bd ,b an interesting manner of occurrence of these misleading bodies is represented4 ,the framework of cells enclosing the nest of coprolites in fig4 #bd ,b1 represents the outer tissues of a ,lepidodendroid or a ,sigillarian leaf2 the inner tissues have been destroyed and the cavity is now occupied by what may possibly be the excreta of the wood-eating animal4 ,some of the oval spore-like structures met with in plant tissues may1 as ,renault has suggested1 be the eggs of an ,arthropod#aee4 ,in a section of a calcareous ,coal-,measure nodule in the ,williamson collection 7,british ,museum7#aef there occur several fungal spores or possibly oogonia lying among imperfectly preserved ,stigmarian appendages4 ,associated with these are numerous dark coloured and larger bodies consisting of a cavity bounded by a simple membrane2 the larger bodies may well be the eggs of some ,arthropod or other animal4 ,sidenote3 ,,photography ,,and ,,illustration4 ,in looking through the collections of ,coal-,measure plants in the ,museums of ,berlin1 ,vienna and other continental towns1 one cannot fail to be struck with the larger size of many of the specimens as compared with those usually seen in ,english ,museums4 ,the facilities afforded in the ,state ,collieries of ,germany to the scientific investigator may account in part at least for the better specimens which he is able to obtain4 ,it would no doubt be a great gain to our collections of ,coal-,measure plants if arrangements could be made in some collieries for the preservation of the finer specimens met with in the working of the seams1 instead of breaking up the slabs of shale and consigning everything to the waste heaps4 ,there is one more point which should be alluded to in connection with possible sources of error1 and that is the essential importance of accuracy in the illustration of specimens1 especially as regard type-specimens4 ,it is often impossible to inspect the original fossils which have served as types1 and it is of the utmost importance that the published figures should be as faithful as possible4 ,m4 ,crpin#aeg of ,brussels1 in an article on the use of photography in illustrating1 has given some examples of the confusion and mistakes caused by imperfect drawings4 ,it does not require a long experience of palaeobotanical work to demonstrate the need of care in the execution of drawings for reproduction4 ,,chapter ,,vi4 ,,nomenclature4 8,i do not think more credit is due to a man for defining a species1 than to a carpenter for making a box40 ,,charles ,,darwin1 ,life and ,letters1 ,vol4 ,i41 p4 #cga4 ,any attempt to discuss at length the difficult and thorny question of nomenclature would be entirely out of place in an elementary book on fossil plants1 but there are certain important points to which it may be well to draw attention4 ,when a student enters the field of independent research1 he is usually but imperfectly acquainted with the principles of nomenclature which should be followed in palaeontological work4 ,after losing himself in a maze of endless synonyms and confused terminology1 he recognises the desirability of adopting some definite and consistent plan in his method of naming genera and species4 ,it is extremely probable that whatever system is made use of1 it will be called in question by some critics as not being in strict conformity with accepted rules4 ,the opportunities for criticism in matters relating to nomenclature are particularly numerous1 and the critic who may be but imperfectly familiar with the subject-matter of a scientific work is not slow to avail himself of some supposed eccentricity on the part of the author in the manner of terminology4 ,the true value of work may be obscured by laying too much emphasis on the imperfections of a somewhat heterodox nomenclature4 ,on the other hand good systematic work is often seriously spoilt by a want of attention to generally accepted rules in naming and defining species4 ,it is essential that those who take up systematic research should pay attention to the necessary though secondary question of technical description4 ,sidenote3 ,,rules ,,for ,,nomenclature4 ,in inventing a new generic or specific name1 it is well to adhere to some definite plan as regards the form or termination of the words used4 ,to deal with this subject in detail1 or to recapitulate a series of rules as to the best method of constructing names whether descriptive or personal1 would take us beyond the limits of a single chapter4 ,the student should refer for guidance to such recognised rules as those drawn up by the late ,mr ,strickland and others at the instance of the ,british ,association#aeh4 ,it is not infrequently the case that the same generic name has been applied to a fossil and to a recent species4 ,such a double use of the same term should always be avoided as likely to lead to confusion1 and as tending to admit a divorce between botany and palaeobotany4 ,in the course of describing a collection of fossil species1 various problems are bound to present themselves as regards the best method of dealing with certain generic or specific names4 ,a few general suggestions may prove of use to those who are likely to be confronted with the intricacies of scientific and pseudoscientific terminology4 ,in writing the name of a species1 it is important to append the name1 often in an abbreviated form1 of the author who first proposed the accepted specific designation4 ,stigmaria ficoides ,brongn4 written in this form records the fact that ,brongniart was the author of the specific name ficoides4 ,it means1 moreover1 that ,brongniart not only suggested the name1 but that he was the first to give either a figure or a diagnosis of this particular fossil4 ,it is frequently the case that a specific name is proposed for a new species1 without either figures or description2 such a name is usually regarded as a nomen nudum1 and must yield priority to the name which was first accompanied by some description or illustration sufficiently accurate to afford a means of recognition4 ,a practice which may be recommended on the score of convenience is to write the name of the author of a species in brackets if he was not the first to use the generic as well as the specific name4 ,onychiopsis ,mantelli 7,brongn47 tells us that ,brongniart founded the species1 but made use of some other generic name than that which is now accepted4 ,this leads us to another point of some importance4 ,brongniart described this characteristic ,wealden fern under the name ,sphenopteris ,mantelli2 ,sphenopteris being one of those extremely useful provisional generic terms which are used in cases where we have no satisfactory proof of precise botanical affinity4 ,sphenopteris stands for fern fronds having a certain habit1 form of segment and venation1 and in this wide sense it necessarily includes representatives of various divisions and genera of ,filices4 ,if an example of a sphenopteroid frond is discovered with sori or spores sufficiently well preserved to enable us to determine its botanical position within narrower limits1 we may with advantage employ another genus in place of the purely artificial form-genus which was originally chosen as a consequence of imperfect knowledge4 ,fronds of this ,wealden fern have recently been found with well defined fertile segments having a form apparently identical with that which characterises the polypodiaceous genus ,onychium4 ,for this reason the name ,onychiopsis has been adopted4 ,it is safer and more convenient to use a name which differs in its termination from that of the recent plant with which we believe the fossil to be closely related4 ,a common custom is to slightly alter the recent name by adding the termination -opsis or -ites4 ,there are several other provisional generic terms that are often used in ,fossil ,botany1 and which might be advantageously chosen in many cases where the misleading resemblance of external form has often given rise to the use of a name implying affinities which cannot be satisfactorily demonstrated4 ,it was the custom of some of the earliest writers1 in spite of their habit of using the names of recent ,flowering plants for extinct ,palaeozoic species of ,vascular ,cryptogams1 to adopt also general and comprehensive terms4 ,we find such a name as ,lithoxylon employed by ,lhwyd#aei in #afii as a convenient designation for fossil wood4 ,sidenote3 ,,the ,,rule ,,of ,,priority4 ,one of the most important and frequently disputed questions associated with the naming of species is that of priority4 ,no name given to a plant in pre-,linnaean days need be considered1 as our present system of nomenclature dates from the institution of the binominal system by ,linnaeus4 ,as a general rule1 which it is advisable to follow1 the specific name which was first given to a plant1 if accompanied by a figure or diagnosis1 should take priority over a name of later date4 ,if ,a in #ahej describes a species under a certain name1 and in #ahfj ,b proposes a new name for the same species1 either in ignorance of the older name or from disapproval of ,a's choice of a specific term1 the later name should not be allowed to supersede ,a's original designation4 ,such a rule is not only just to the original author1 but is one which1 if generally observed1 would lead to less confusion and would diminish unnecessary multiplication of specific names4 ,some writers would have us conform in all cases to this rule of priority1 which they consistently adhere to apart from all considerations of convenience or long-established custom4 ,there are1 however1 cogent reasons for maintaining a certain amount of freedom4 ,while accepting priority as a good rule in most cases1 it is unwise to allow ourselves to be too servile in our conformity to a principle which was framed in the interests of convenience1 if the strict application of the rule clearly makes for confusion and inconvenience4 ,a name may have been in use for say eighty years1 and has become perfectly familiar as the recognised designation of a particular fossil2 it is discovered1 however1 that an older name was proposed for the same species ninety years ago1 and therefore according to the priority rule1 we must accustom ourselves to a new name in place of one which is thoroughly established by long usage4 ,from a scientific point of view1 the ideal of nomenclature is to be plain and intelligible4 ,to prefer priority to established usage entails obscurity and confusion4 ,if priority is to be the rule which we must invariably obey in the shadowy hope that by such means finality in nomenclature#afj may be reached1 it becomes necessary for the student to devote no inconsiderable portion of his time to antiquarian research1 with a view to discover whether a particular name may be stamped with the hallmark of #8the very first4' ,while admitting the advisability of retaining as a general principle the original generic or specific name1 the extreme subservience to #8the priority craze' without regard to convenience1 would seem to lead irresistibly to the view that 8botanists who waste their time over priority are like boys who1 when sent on an errand1 spend their time in playing by the roadside#afa40 ,sidenote3 ,,terminology ,,and ,,convenience4 ,there is another point which cannot be satisfactorily settled in all cases by a rigid adherence to an arbitrary rule4 ,how far should we regard a generic name in the sense of a mere mark or sign to denote a particular plant1 or to what extent may we accept the literal meaning of the generic term as an index of the affinity or character of the plant8 ,if we consider the etymology of many generic names1 we soon find that they are entirely inappropriate as aids in recognizing the true taxonomic position of the plants to which they are applied4 ,the generic name ,calamites was first suggested by the supposed resemblance of this ,palaeozoic plant to recent reeds4 ,if considered etymologically1 it is merely a record of a past mistake1 but it would be absurd to discard such a well-known name on the grounds that the genus is a ,vascular ,cryptogam and far removed from reeds4 ,on the other hand1 there often arise cases which present a real difficulty4 ,the following example conveniently illustrates two distinct points of view as regards generic nomenclature4 ,in #ahge ,saporta described and figured a fragment of a fossil plant from the ,jurassic beds of ,france as ,cycadorachis armata#afb2 the name being chosen in the belief that the specimen was part of a cycadean petiole1 and there were good grounds for such a view4 ,a few years ago ,mr ,rufford discovered more perfect specimens1 in the ,wealden rocks of ,sussex1 clearly belonging to ,saporta's genus1 and these afforded definite evidence that ,saporta had been deceived by the imperfection of the specimens as to their true botanical position4 ,owing to the obviously misleading name first given to this plant1 ,i ventured to substitute ,withamia#afc for ,cycadorachis1 and chose such a term in preference to one denoting affinity1 on account of the difficulty of placing the plant in a definite class or family4 ,on the other hand1 it has been objected that the original name1 despite its meaningless meaning--if the expression may be used--should be retained4 ,a friendly critic#afd1 in writing of the proposed change of ,cycadorachis1 urges the importance of adhering to the name which was first applied to a genus4 ,the same author pertinently remarks that we can no more dispense with a nomenclature than we can dispense with language4 ,we may extend the comparison and point out that in language1 as in scientific nomenclature1 conciseness1 clearness and convenience should be kept in view as guiding principles4 ,the student must judge for himself what course to follow in each case4 ,while adhering as far as possible to a consistent plan1 he must take care that he does not allow his own judgment to be completely over-ridden by a blind obedience to fixed rules1 which if pressed too far may defeat their own ends4 ,,part ,,ii4 ,,systematic4 ,,chapter ,,vii4 ,,thallophyta4 ,the divisions of the plant kingdom dealt with in the following chapters of ,volume ,i4 are taken in their natural sequence1 beginning with the lowest and passing gradually to the highest groups4 ,the list of the classes and families included in ,chapters ,,vii4-,,xi4 is given in the table of contents preceding ,chapter ,i4 ,thallophytes are of the simplest type1 but they exhibit a very wide range as regards both the structure and differentiation of the vegetative body and the methods of reproduction4 ,in some cases the individual consists of a minute simple cell which multiplies by cell-division2 in others the body or thallus is made up of a number of similar units1 while in a great number of forms there is a well-marked physiological division of labour1 as expressed both in the external division of the thallus into distinct organs corresponding in function to the root1 stem1 and leaves of the higher plants1 and further in the high degree of histological differentiation of the tissues4 ,in other thallophytes1 again1 the thallus is a coenocyte either unseptate or incompletely septate2 that is1 the individual consists of a single cell differing from a true plant-cell1 in the stricter sense of the term1 in possessing several nuclei1 in other words1 the thallus is divided up into compartments by transverse septa1 but each division contains more than one nucleus4 ,such coenocytic plants may show well-marked external differentiation of the thallus into members or parts subserving different functions4 ,a similar wide range is covered by the methods of reproduction among thallophytes4 ,i4 ,,peridiniales4 ,the organisms included under this head are of little importance from a palaeontological point of view1 but a brief reference may be made to them as a section of the ,thallophyta4 ,the ,peridiniales include very small single-celled organisms which have often been described as occupying a position on the borderland between animals and plants1 lying on the 8shadowy boundary between animal and vegetable life40 ,the individuals are rarely naked1 more frequently they are covered with a cellulose or mucilaginous investment which has frequently the form of two or more minute armour-like plates of a limiting membrane4 ,the chromatophores are green1 yellow1 brown or colourless4 ,simple division is the usual method of reproduction1 but spores have been described as occurring in some species4 ,the motile forms are provided with cilia4 ,the ,peridiniaceae1 a section of the ,peridiniales1 are regarded as nearly related to the ,diatoms4 ,the ,peridiniales play an important rle in the ,plankton flora of the sea and freshwater lakes1 and have a world-wide distribution4 ,in the narrative of the ,challenger cruise they are described as occasionally filling the tow-nets with a yellow coloured slime#afe4 ,some genera1 such as ,ceratium1 are found in enormous numbers off the ,british coast4 ,as an example of the occurrence of fossil representatives of the ,peridiniaceae reference may be made to one of two species of ,peridinium described by ,ehrenberg in #ahcf4 ,these were found in a siliceous rock described as ,cretaceous in age from ,delitzsch in ,saxony4 ,a comparison of ,ehrenberg's figures of the fossil species ,peridinium pyrophorum ,ehrenb4#aff1 with those of the recent species ,peridinium divergens ,ehrenb41 as given by ,schtt#afg and other writers1 brings out clearly the very close resemblance if not identity of the two forms4 ,btschli#afh in his account of the ,dinoflagellata in ,bronn's ,thier-,reich confirms ,ehrenberg's determination of ,peridinium pyrophorum1 and points out its striking agreement with the recent species4 ,,ii4 ,,coccospheres ,,and ,,rhabdospheres4 7,organisms of doubtful affinity47 ,our knowledge of these minute calcareous organisms is derived from ,huxley's description of coccoliths from the ,atlantic in #aheg1 and from the accounts of ,wallich1 ,john ,murray1 and other writers4 ,in the first volume of the narrative of the ,challenger cruise#afi and in the volume on deep-sea deposits#agj these minute forms of life are figured and described4 ,in the latter volume both genera are spoken of as extremely abundant in the surface waters of the tropical and temperate regions of the open ocean1 and as forming an important constituent of the ,globigerine ooze2 they are said to occur entangled in the gelatinous substance of the ,radiolarians1 ,diatoms1 and ,foraminifera1 and are very common in the stomachs of ,salps1 ,pteropods and other pelagic animals4 ,rhabdospheres are rare in regions where the temperature of the water sinks below #fe ,f42 the ,coccospheres occur in tropical and temperate latitudes1 and extend further north and south than the ,rhabdospheres4 ,as regards their botanical position1 ,john ,murray expresses the view that they are in all probability pelagic algae4 ,in the interesting memoir by ,schtt on the ,pflanzenleben der ,hochsee#aga there occurs a short reference to the forms described in the ,challenger ,reports1 but they were not obtained by the staff of the ,hensen ,plankton ,expedition and ,schtt's remarks are not based therefore on personal observations4 ,while admitting the existence of such bodies1 he points out that ,zoologists have referred ,coccospheres and ,rhabdospheres to the algae as organisms which cannot be included in any group of animals1 and ,schtt is unable to recognise a sufficient reason for referring them to this class of plants4 ,it is suggested indeed that they may be purely inorganic structures4 ,illustration3 ,,fig4 #be4 7,from ,murray and ,blackman74 ,a1 ,coccosphere #acjj4 ,b1 ,rhabdosphere #ijj4 ,c1 ,portion of the same #acjj4 ,d1 ,rhabdosphere of another type1 in optical section #aijj4 ,e1 ,the same in surface view #aijj4 ,f1 ,end of one of the trumpet-shaped appendages of ,e4 ,the most recent account of these two genera is by ,messrs ,g4 ,murray and ,blackman a short notice in ,nature for ,april #a1 #ahigagb4 ,numerous examples of ,coccospheres and ,rhabdospheres were obtained by ,capt4 ,milner of the ,r4,m4,s4 ,para during a voyage to ,barbados by allowing the sea water to enter the feed-pipe of the boiler through a fine muslin net4 ,all the forms described in the ,challenger ,reports were met with1 and an examination of the material by means of extremely high objectives has confirmed the original account of the genera1 and added some points to our previous knowledge4 ,coccospheres 7fig4 #be ,a74 ,spherical bodies of exceedingly small size1 consisting of a central protoplasmic vesicle covered with overlapping circular calcareous scales1 each of which is attached to the minute cell by a button-like projection4 ,the scales are frequently found detached and are then spoken of as ,coccoliths4 ,rhabdospheres 7fig4 #be ,b-,f74 ,spherical bodies1 extremely minute1 consisting of a single cell1 on the surface of which are embedded numerous calcareous plates bearing long blunt spines 7fig4 #be1 ,c7 or beautiful trumpet-like appendages 7fig4 #be1 ,d-,f74 ,the detached plates of ,rhabdospheres are known as ,rhabdoliths4 ,in addition to the text-figures of ,coccospheres and ,rhabdospheres in the ,challenger ,reports1 the same structures are shown in samples of globigerine ooze figured in ,plate ,,xi4 of the ,monograph on deep-sea deposits4 ,in a recent number of ,nature ,messrs ,dixon and ,joly#agc have announced the discovery of ,coccoliths and ,coccospheres in the coastal waters off ,south ,county ,dublin4 ,they estimate that in one sample of water taken about three miles from the ,irish coast there were #bjj ,coccoliths in each cubic centimetre of sea water4 ,the interest of these calcareous bodies from a palaeobotanical point of view lies in the fact that similar forms have been recognized in the ,chalk and the ,upper ,lias4 ,sorby1 in his memorable ,address delivered before the ,geological ,society in #ahgi1 refers to the abundance of ,coccoliths in sections of chalk which he examined#agd4 ,rothpletz#age has recently recorded the occurrence of numerous ,coccoliths1 #e-ab in diameter1 associated with the skeleton of a horny sponge 7,phymatoderma7 of ,liassic age4 ,the question of the nature of ,coccospheres and ,rhabdospheres cannot be regarded as definitely settled4 ,it has been shown by ,j4 ,murray1 and more recently by ,g4 ,murray and ,v4 ,h4 ,blackman1 that on the solution of the calcareous material by a weak acid there remains a small gelatinous body apparently protoplasmic in nature4 ,we may at least express the opinion that ,schtt's suggestion as to their being inorganic must be ruled out of court4 ,it would appear that they are extremely minute unicellular organisms characterised by a delicate calcareous armour consisting of numerous plates or scales4 ,we know nothing as to their life-history1 and cannot attempt to determine their affinities with any degree of certainty until further facts are before us4 ,it is not improbable that they are algae of an extremely minute size1 and the evidence so far obtained would lead us to regard them as complete individuals rather than the reproductive cells of some larger organism4 ,mr ,george ,murray is of opinion that they are certainly algae1 but he considers that they cannot be included in any existing family4 ,it is conceivable that they may be minute eggs or reproductive cells of animals or plants1 but on the whole the balance of probability would seem to be in favour of regarding them as autonomous organisms4 ,,iii4 ,,schizophyta4 ,a4 ,,schizophyceae 7,,cyanophyceae74 ,b4 ,,schizomycetes 7,bacteria74 ,in this group are included small single-celled plants of an extremely low type of organisation1 in which reproduction takes the form of multiplication by simple cell-division1 or the formation of spores4 ,the characteristic method of reproduction by division has given rise to the general term ,fission-plants for this lowest sub-class in the vegetable kingdom4 ,in many cases the members of this sub-class contain chlorophyll1 and associated with it a blue-green colouring matter2 such plants are classed together as the ,blue-green algae1 ,cyanophyceae1 or ,schizophyceae4 ,others1 again1 are destitute of chlorophyll1 and may be conveniently designated ,schizomycetes or ,fission-fungi4 ,seeing how close is the resemblance and relationship between the members of the sub-class1 it has been the custom to include them as two parallel series under the general head1 ,schizophyta1 rather than to incorporate them among the ,algae and ,fungi respectively4 ,a4 ,,schizophyceae 7,,cyanophyceae or ,blue-green ,algae74 ,chroococcaceae4 ,thallus of a single cell1 the cells may be either free1 or more usually joined together in colonies enveloped by a common gelatinous matrix1 formed by the mucilaginous degeneration of the outer portion of the cell-walls4 ,reproduction by means of simple division or resting cells4 ,nostocaceae4 ,thallus consists of simple or branched rows of cells in which special cells known as heterocysts often occur4 ,reproduction by means of germ-plants or hormogonia1 or by resting cells specially modified to resist unfavourable conditions4 ,in both families the individuals are surrounded by a gelatinous envelope1 which in some genera assumes the form of a conspicuous and comparatively resistant sheath4 ,marine1 freshwater1 and aerial forms are represented among recent genera4 ,several species occur as endophytes1 living in the tissues or mucilage-containing spaces in the bodies of higher plants4 ,in addition to the frequent occurrence of blue-green algae in freshwater streams and on damp surfaces1 certain forms are particularly abundant in the open sea#agf1 and in lakes or meres#agg where they are the cause of what is known in some parts of the country as 8the breaking of the meres0 78,fleurs d'eau074 ,from the narrative of the cruise of the ,challenger1 we learn that the ,oscillariaceae are especially abundant in the surface waters of the ocean4 ,the 8sea sawdust0 so named by ,cook's sailors#agh1 and the same floating scum collected by ,darwin#agi1 affords an illustration of the abundance of some of these blue-green algae in the sea4 ,another manner of occurrence of these plants has been recorded by different writers1 which is of special importance from the point of view of fossil algae4 ,on the shores of the ,great ,salt ,lake1 ,utah1 there are found numerous small oolitic calcareous bodies thrown up by the waves#ahj4 ,these are coated with the cells of ,glocapsa and ,glotheca1 two genera of the ,chroococcaceae4 ,sections of the grains reveal the presence of the same forms in the interior of the calcareous matrix1 and it has been concluded1 on good evidence that the algae are responsible for the deposition of the carbonate of lime of the oolitic grains4 ,by extracting the carbonic acid which they require as a source of food1 from the waters of the lake1 the solvent power of the water is decreased and carbonate of lime is thrown down4 ,in similar white grains from the ,red ,sea#aha there is a central nucleus in the form of a grain of sand1 and cells of ,chroococcaceae occur in the surrounding carbonate of lime as in the ,salt ,lake oolite4 ,prof4 ,cohn of ,breslau in #ahfb demonstrated the importance of low forms of plant life in the deposition of the ,carlsbad 8,sprudelstein#ahb40 ,on the bottom of ,lough ,belvedere1 near ,mullingar in ,ireland#ahc1 there occur numerous spherical calcareous pebbles1 of all sizes up to that of a filbert4 ,from a pond in ,michigan 7,u4,s4,a47#ahd similar bodies have been obtained varying in diameter from one to three and a half inches4 ,in the former pebbles a species of ,schizothrix1 one of the ,nostocaceae occurs in abundance1 in the form of chains of small cells enclosed in the characteristic and comparatively hard tubular sheath1 and associated with ,schizothrix fasciculata there have been found ,nostoc cells and the siliceous frustules of ,diatoms4 ,in the ,michigan nodules the same ,schizothrix occurs1 associated with ,stigonema and ,dichothrix1 other genera of the ,nostocaceae4 ,one of the ,michigan pebbles is shown in section in fig4 #cb ,d4 ,sidenote3 ,,oolitic ,,structure4 ,the connection between the well-known oolitic structure1 characteristic of rocks of various ages in all parts of the world1 and the presence of algal cells is of the greatest interest from a geological point of view4 ,in recent years considerable attention has been paid to the structure of oolitic rocks1 and in many instances there have been found in the calcareous grains tubular structures suggestive of simple cylindrical plants1 which have probably been concerned in the deposition of the carbonate of lime of which the granules consist4 ,in #ahhj ,messrs ,nicholson and ,etheridge#ahe recorded the occurrence of such a tubular structure in calcareous nodules obtained from a rock of ,ordovician age in the ,girvan district of ,scotland4 ,these ,authors considered the tubes to be those of some ,rhizopod1 and proposed to designate the fossil ,girvanella4 ,girvanella 7fig4 #bf74 ,messrs ,nicholson and ,etheridge defined the genus as follows3-- 8,microscopic tubuli1 with arenaceous or calcareous 787 walls1 flexuous or contorted1 circular in section1 forming loosely compacted masses4 ,the tubes1 apparently simple cylinders1 without perforations in their sides1 and destitute of internal partitions or other structures of a similar kind40 ,illustration3 ,,fig4 #bf4 ,girvanella problematica1 ,eth4 and ,nich4 ,tubules of ,girvanella lying in various positions and surrounding an inorganic #8nucleus' or centre4 ,from a section of ,wenlock limestone1 ,may ,hill4 #fe ,since this diagnosis was published very many examples of similar tubular fossils have been described by several writers in rocks from widely separated geological horizons4 ,the accompanying sketch 7,fig4 #bf71 drawn from a micro-photograph kindly lent to me by ,mr ,wethered of ,cheltenham1 who has made oolitic grains a special subject of careful investigation1 affords a good example of the occurrence of such tubular structures in an oolitic grain of ,silurian age from the ,wenlock limestone of ,may ,hill1 ,gloucestershire#ahf4 ,in the centre is a crystalline core or nucleus round which the tubules have grown1 and presumably they had an important share in the deposition of the calcareous substance4 ,the nature of ,girvanella1 and still more its exact position in the organic world1 is quite uncertain2 it is mentioned rather as propos of the association of recent ,cyanophyceae with oolitic structure1 than as a well-defined genus of fossil algae4 ,in the typo description of the calcareous nodules from ,michigan1 ,murray speaks of the ,schizothrix filaments at the surface of the pebbles as fairly intact1 while nearer the centre only sheaths were met with4 ,it is conceivable that in some of the tubular structures referred to ,girvanella we have the mineralised sheaths of a fossil ,cyanophyceous genus#ahg4 ,the organic nature of these tubules has been a matter of dispute1 but we may probably assume with safety that in some at least of the fossil oolitic grains there are distinct traces of some simple organism which was in all likelihood a plant4 ,some authors have suggested that ,girvanella is a calcareous alga which should be included in the family ,siphoneae#ahh4 ,as a matter of fact we must be content for the present to leave its precise nature as still sub judice1 and while regarding it as probably an alga1 we may venture to consider it more fittingly discussed under the ,schizophyta than elsewhere4 ,wethered#ahi would go so far as to refer oolitic structure in general to an organic origin4 ,while admitting that a ,girvanella-like structure has been very frequently met with in oolitic rocks1 it would be unwise to adopt so far-reaching a conclusion4 ,it is at least premature to refer the formation of all oolitic structure to algal agency1 and the evidence adduced is by no means convincing in every case4 ,the discovery of ,girvanella and allied forms in rocks from the ,cambrian#aij1 ,ordovician1 ,silurian1 ,carboniferous1 ,jurassic and other systems is a striking fact1 and lends support to the view that oolitic structure is in many cases intimately associated with the presence of a simple tubular organism4 ,among recent algae we find different genera1 and representatives of different families1 growing in such a manner and under such circumstances as are favourable to the formation of a ball-like mass of algal threads1 which may or may not be encrusted with carbonate of lime4 ,similarly as regards oolitic grains of various sizes1 and the occurrence in rocks of calcareous nodules1 the tubular structure is not always of precisely the same type1 and cannot always be included under the genus ,girvanella4 ,several observers have recorded the occurrence of low forms of plant-life in the waters of thermal springs4 ,it has been already mentioned that ,cohn described the occurrence of simple plants in the warm ,carlsbad ,springs1 and fission-plants of various types have been discovered in the thermal waters of ,iceland1 the ,azores#aia1 ,new ,zealand1 the ,yellowstone ,park1 ,japan1 ,india1 and numerous other places4 ,a few years ago ,mr ,weed1 of the geological survey of the ,united ,states1 published an interesting account of the formation of calcareous travertine and siliceous sinter in the ,yellowstone ,park district#aib4 ,this author emphasizes the important rle of certain forms of plants in the building up of the calcareous and siliceous material4 ,among other forms of frequent occurrence1 ,calothrix gypsophila and a species ,leptothrix are mentioned1 the former being a member of the ,nostocaceae1 allied to ,rivularia1 and the latter a genus of ,schizomycetes4 ,in many of the springs there are found masses of algal jelly like those previously described by ,cohn in the ,carlsbad waters4 ,sections of such dried jelly showed a number of interlaced filaments with glassy silica between them4 ,weed refers to the occurrence of small gritty particles in this mucilaginous material4 ,these are calcareous oolitic granules which are eventually cemented together into a compact and firm mass of travertine by the continued deposition of carbonate of lime4 ,the presence of the plant filaments is often difficult to recognise in the 8leathery sheet of tough gelatinous material10 or in 8the skeins of delicate white filaments0 which make up the travertine deposits4 ,sidenote3 ,,borings ,,in ,,shells4 ,under the head of ,cyanophyceae1 mention should be made of the recent genus ,hyella#aic1 which occurs as a perforating or boring alga in the calcareous shells of molluscs4 ,on dissolving the carbonate of lime of shells perforated by this alga1 the latter is isolated and appears to consist of rows of small cells1 with possibly some sporangia containing spores4 ,other boring algae have been recorded among the ,chlorophyceae1 and recently a member of the ,rhodophyceae#aid has been found living in the substance of calcareous shells4 ,such examples are worthy of note in view of the not infrequent occurrence of fossil corals1 shells and fish-scales1 which have evidently been bored by an organism resembling in form and manner of occurrence these recent algal borers4 ,the occurrence of small ramifying tubes in recent and fossil corals1 fish-scales1 and bones was long ago pointed out by ,quekett#aie1 ,klliker#aif1 ,rose#aig and other writers#aih4 ,these narrow tubular cavities have generally been attributed to the boring action of some parasitic organism1 either a fungus or an alga4 ,in #ahgf ,duncan published two important papers#aii dealing with the occurrence of such tubes in recent corals1 as well as in the calcareous skeleton of ,calceolina1 ,goniophyllum and other ,palaeozoic1 ,mesozoic and ,tertiary species of corals4 ,this writer attributed the formation of the cavities in the case of the fossil species to the action of a fungus which he named ,palaeachlya perforans1 and considered as very nearly related to ,achlya penetrans found in the 8dense sclerenchyma0 of recent corals4 ,in fig4 #bg ,a4 is reproduced one of the drawings given by ,rose#bjj in his paper published in #ahee2 it shows a section of a fish-scale from the ,kimeridge clay which has been attacked by a boring organism4 ,rose attributes the dichotomously branched canals to some 8infusorial parasite40 ,illustration3 ,,fig4 #bg4 ,a1 ,section of a fish-scale from the ,kimeridge ,clay1 showing branched canals1 made by a boring organism1 #he4 ,b1 ,section of a ,solen shell1 penetrated in all directions by the boring thallus of ,ostracoblabe 7a fungus871 #ccj4 ,c1 ,piece of the thallus of ,ostracoblabe isolated by decalcification1 #gde4 ,a1 after ,rose4 ,b and ,c1 after ,bornet and ,flahault4 ,in the important paper by ,,mm4 ,bornet and ,flahault on perforating algae a full description is given of various boring forms belonging to the ,chlorophyceae and the ,cyanophyceae#bja4 ,the canals which these algae produce in calcareous shells and other hard substances are of the same type as those previously described in fossil corals1 fish-scales and bones4 ,in dealing with living perforating ,thallophytes the colour and other cell-contents often enable us to distinguish between algae and fungi1 but in fossil specimens such tests cannot be applied4 ,the fossil tubular borings may or may not show traces of the transverse septa and reproductive cells2 it is often the case that no trace of the organism has been left1 but only the canals by which it penetrated the calcareous or bony skeleton4 ,in some of the examples of ,palaeachlya figured by ,duncan there appear to be numerous spores in some of the sections1 but it is generally a very difficult and often an impossible task to discriminate between the borings of fungi and algae in fossil material4 ,fig4 #bg ,b1 which is copied from one of ,bornet and ,flahault's drawings1 represents a piece of ,solen shell riddled with small canals made by the organism which has been named by the ,french authors ,ostracoblabe implexa1 and regarded by them as a fungus4 ,fig4 #bg ,c represents a small piece of the vegetative body of ,ostracoblabe obtained from a decalcified shell4 ,in endeavouring to determine the organism which has produced borings in fossil corals or shells1 it must be borne in mind that some forms of canals or passages may have been the work of perforating sponges1 but these are larger in diameter than those made by algae or fungi4 ,by some writers#bjb the tubular cavities in shells have been referred to true algae1 but others consider them to be of fungal origin4 ,as an example of a fossil alga referred to the ,cyanophyceae1 the genus ,zonatrichites#bjc may be quoted4 ,bornemann1 who first described the specimens1 points out the close resemblance in habit to some members of the recent ,rivulariaceae4 ,zonatrichites4 ,the author of the genus defines it as follows3-- 8,a calcareous alga1 with radially arranged filaments1 forming hemispherical or kidney-shaped layers1 growing on or enclosing other bodies4 ,parallel or concentric zones are seen in cross-section1 formed by the periodic growth of the alga1 the older and dead layers serving as a foundation on which the young filaments grow in radially arranged groups40 ,the nodules which are apparently formed by species of this genus occur in various sizes and shapes2 ,bornemann describes one hemispherical mass #h cm4 broad and #d cm4 thick4 ,in some cases the organism has given rise to oolitic spherules1 which in radial section exhibit the branched tubular cells spreading in fan-shaped groups from the centre of the oolitic grain4 ,the section parallel to the surface of a nodule presents the appearance of a number of circular or elliptical tubes cut across transversely or more or less obliquely4 ,the resemblance between the fossil and a specimen of the recent species ,zonatrichia calcivora ,braun1 is certainly very close1 but it is very difficult1 in the absence of material exhibiting more detailed structure than is shown in the specimens described by ,bornemann1 to decide with any certainty the true position of the fossil4 ,the figures do not enable us to recognise any trace of cells in the radiating tubes4 ,it is possible that we have in ,zonatrichites an example of a ,cyanophyceous genus in which only the sheaths of the filaments have been preserved4 ,in any case it is probable that this ,mesozoic species affords another instance of a fossil alga which has been responsible for certain oolitic or other structures in limestone rocks4 ,the species described by ,bornemann was obtained from a ,breccia near ,lissau in ,silesia1 of ,keuper age4 ,m4 ,renault has recently described certain minute structures in a ,palaeozoic coprolite to which he gives the name ,gloioconis ,borneti#bjd1 and which he regards as a ,permian gelatinous alga similar to the well-known recent genus ,glocapsa4 ,the appearances revealed in a section of the coprolite are interpreted by this author as a collection of small colonies of a unicellular gelatinous alga in various stages of development4 ,renault's figure shows a spherical group of faintly outlined and cloudy bodies1 most of which include one or two small dark spots4 ,the latter are regarded as the cells of the alga1 and the surrounding cloudy substance is described as the gelatinous sheath4 ,the absence of a nucleus in these extremely minute fossil cells 7#h-aj in diameter7 is referred to as an argument in favour of referring the organism to the ,cyanophyceae rather than to the ,chlorophyceae4 ,it is possible that the ill-defined structure described by ,renault may be a petrified alga1 but there is not sufficient evidence to warrant a decided opinion2 the absence of nuclei can hardly be taken seriously in such a case as this as an argument in favour of the ,cyanophyceae4 ,sidenote3 ,,cyanophyceae4 ,although our exact knowledge of fossil ,cyanophyceae is extremely small1 it is probable that such simple forms of plants existed in abundance during the past ages in the earth's history4 ,several writers have expressed the opinion that the blue-green algae may be taken as the modern representatives of those earliest plants which first existed on an archaean land-surface4 ,the living species possess the power of resisting unfavourable conditions in a marked degree1 and are able to adapt themselves to very different surroundings4 ,their occurrence in hot springs proves them capable of living under conditions which are fatal to most plants1 and suggests the possibility of their occurrence in the heated waters which probably constituted the medium in which vegetable life began4 ,an interesting example of the growth of blue-green algae under unfavourable conditions was recorded in #ahhf by ,dr ,treub#bje of the ,buitenzorg ,gardens1 ,java4 ,in #ahhc a considerable part of the island ,krakatoa1 situated in the ,straits of ,sunda1 between ,sumatra and ,java1 was entirely destroyed by a terrific volcanic explosion4 ,what remained had been reduced to a lifeless mass of hot volcanic ashes4 ,three years later1 ,treub visited the island1 and found that several plants had already established themselves on the volcanic rocks4 ,various ferns and flowering plants were recorded in ,treub's description of this newly established flora4 ,it seemed that the barren rocky surface had been prepared for the more highly organised plants by the action of certain forms of ,cyanophyceae1 which were able to live under conditions which would be fatal to more complex types4 ,in the petrified tissues of fossil plants there are occasionally found small spherical vesicles1 with delicate limiting membranes1 in the cavities of parenchymatous cells or in the elements of vascular tissue4 ,some of these spherical inclusions have been described as possibly simple forms of endophytic algae#bjf1 such as we are now familiar with in species of the ,cyanophyceae and other algae4 ,so far1 however1 no recorded instance of such fossil endophytic algae is entirely satisfactory4 ,some of the cells figured by ,williamson as possibly algae1 endophytic in the tissues of ,coal-,measure plants1 are no doubt thin-walled vesicles which formed part of a highly vacuolated cell-contents4 ,examples of such vesicles in living and fossil cells are shown in fig4 #db4 ,the fact that the contents of living plant tissues have been erroneously described as endophytic organisms1 should serve as a warning against describing fossil endophytes without the test of good evidence to support them4 ,the description of a fossil ,nostoc by the late ,prof4 ,heer#bjg from the ,tertiary rocks of ,switzerland cannot be accepted as a trustworthy example of a fossil plant1 much less of a genus of recent algae4 ,the application of recent generic names to fossils which are possibly not even organic must do more harm than good4 ,b4 ,,schizomycetes 7,bacteria74 ,it is impossible to draw a sharp line between the two subdivisions of the ,schizophyta4 ,the so-called ,fission-,fungi or ,bacteria differ from the ,schizophyceae or ,fission-,algae in the cell-contents being either colourless1 blood-red or green1 but never blue-green4 ,we may regard the ,bacteria1 generally1 as the lowest forms of plants2 they are extremely simple organisms which have been derived from some primitive types which possessed the power of independent existence and contained chlorophyll--that important substance which enables a plant to obtain its carbon first-hand from the carbon dioxide of the atmosphere4 ,bacteria may be briefly described as single-celled plants1 and as de ,bary suggested comparable in shape to a billiard ball1 a lead pencil or a corkscrew#bjh4 ,a single spherical or cylindrical cell measures about #a in diameter#bji4 ,they occur either singly or in filaments1 or as masses of various shapes consisting of numberless bacterial cells4 ,the nature and manner of life of ,bacteria1 and their extraordinary power of successfully resisting the most unfavourable conditions1 render it probable that they constitute an extremely ancient group of organisms4 ,the wonderful perfection of preservation of many fossil plants enables us to investigate the contents of petrified cells and to examine in minutest detail the histology of extinct plants4 ,to those who are familiar with the possibilities of microscopical research as applied to silicified and calcified fossil tissues1 it is by no means incredible that evidence has been detected of the existence of ,bacteria as far back in the history of the earth as the ,carboniferous and ,devonian periods4 ,were there no trustworthy records of the occurrence of ,bacteria in ,palaeozoic times1 it would still be a natural supposition that these ubiquitous organisms must have been abundantly represented4 ,it has been suggested as a probable conclusion that some forms of ,bacteria1 which produced chemical changes in the soil necessary for the nutrition of plants1 must have existed contemporaneously with the oldest vegetation#baj4 ,the paper-coal of ,toula1 which in some places reaches a thickness of #bj cm41 is a plant-bed of exceptional interest4 ,it differs from ordinary coal in being made up of numberless thin brown-papery sheets associated with a darker coloured substance largely composed of ulmic acid4 ,prof4 ,zeiller#baa1 in an interesting account of the papery layers1 has shown that they consist of the cuticles of a ,lepidodendroid plant1 ,bothrodendron4 ,an examination of a piece of one of the sheets at once reveals the existence of a regular network of which the walls of the meshes are the outlines of the epidermal cells1 the meshes being bridged across by a thin light brown membrane which represents the layer of cuticularised cell-wall of each epidermal cell4 ,at regular intervals and disposed in a spiral arrangement1 we find small gaps in the papery cuticle which mark the position of the ,bothrodendron leaves4 ,these ,palaeozoic cuticles are not petrified2 they are only slightly altered1 and have retained the power of swelling in water1 being able to take up stains like recent tissues4 ,it may reasonably be assumed that the persistent cuticles owe their preservation to a greater power of resistance to destructive agents than was possessed by the other tissues of the plant4 ,it is by no means unlikely1 as ,renault#bab has recently suggested1 that as the ,bothrodendron stem-fragments lay in the swamps or marshes the tissues were gradually eaten away by ,bacteria1 but the cuticles successfully resisted the attacks of the bacterial saprophytes4 ,the same observer has described what he regards as the actual organism which effected this wholesale destruction1 under the name ,micrococcus ,zeilleri4 ,he finds1 after treating the cuticles with ammonia to remove the ulmic acid1 that there occur numerous minute spherical bodies1 each surrounded by a thin envelope1 either singly or in groups on the surface of the cuticular membrane4 ,these vary in size from #e to #a in diameter4 ,i have not been able to detect any satisfactory proof of such ,micrococci in specimens of the paper-coal which were treated according to ,renault's method1 but it is extremely probable that this unusual method of preservation of stem-cuticles is the result of selective bacterial action4 ,renault believes that some of the minute spherulitic structures which are seen in sections of decayed tissues of ,palaeozoic plants owe their origin1 in part1 to the ravages of bacteria4 ,the disorganisation of parenchymatous cells gives rise to a gelatinous substance in which needle-like crystals of silica may be deposited1 from a siliceous solution1 in a matrix which has resulted from bacterial activity4 ,in some of the sections of tissues figured by ,renault#bac the outlines of a few cells are still indicated by fragments of the partially decayed wall1 while in other cells the walls have been completely destroyed by ,bacteria of which some are preserved in the centre of the cell-area1 forming a kind of nucleus to the siliceous spherulites4 ,sidenote3 ,,bacilli4 ,in addition to the ,micrococcus described by ,renault from the ,toula paper-coal1 there are a host of other forms which have been minutely diagnosed and figured by ,profs4 ,renault and ,bertrand#bad4 ,these authors have discovered what they believe to be well-defined species of ,micrococcus and ,bacillus ranging in age from ,devonian to ,jurassic4 ,the material which has afforded the somewhat startling results of their investigations consists partly of the coprolites of reptiles and fishes1 and of silicified and calcified plant tissues4 ,bacillus ,permicus4 ,ren4 and ,bert4#bae 7,fig4 #bh ,b47 ,this ,bacillus1 which was discovered in sections of a ,permian coprolite from ,central ,france1 has the form of cylindrical rods #ab-ad in length1 and #ac-ae broad1 rounded at each end4 ,the rods occur either singly or occasionally1 two or three individuals are joined end to end4 ,fig4 #bh ,b represents a piece of one of ,renault and ,bertrand's sections2 the small rods are clearly seen lying in various directions in the homogeneous matrix of the coprolite4 ,each individual is said to be surrounded by an extremely minute empty space #d in width1 originally occupied by the ,bacillus membrane1 the central rod representing the mineralised cell-contents4 ,in this example the petrifying substance was probably derived from the phosphate of calcium of bones which were attacked by ,bacteria4 ,i am indebted to ,prof4 ,renault for an opportunity of examining specimens of this and other fossil ,bacteria1 and in this particular case there is undoubtedly strong evidence in favour of the author's determination4 ,illustration3 ,,fig4 #bh4 ,a1 ,bacillus ,tieghemi ,ren4 and ,micrococcus ,guignardi ,ren4 ,b1 ,bacillus ,permicus ,ren4 7,after ,renault47 ,bacillus ,tieghemi ,ren4#baf and ,micrococcus ,guignardi ,ren4#bag 7,fig4 #bh ,a47 ,renault has given the name ,bacillus ,tieghemi to certain minute rods #f-aj1 in length1 and #bb-ch broad1 often containing a dark coloured spherical spore-like body #b in diameter1 which have been found in the tissues of a ,coal-,measure plant4 ,the name ,micrococcus ,guignardi has been applied to more or less spherical bodies #bb in diameter1 also met with in silicified plants4 ,a portion of one of ,renault's figures is reproduced in ,fig4 #bh ,a4 ,the faint and broken lines mark the position of the middle lamellae of parenchymatous cells from the pith of a ,calamite4 ,the tissue has been almost completely destroyed1 but the more resistant middle lamellae have been partially preserved4 ,the short and broad rods represent what ,renault terms ,bacillus ,tieghemi2 the small circle in the middle of some of these being referred to as a spore1 and in one specimen shown in the figure1 the second rod at right angles to the first is described as a small daughter-,bacillus formed by the germination of the central spore4 ,the isolated circles in the figure are referred to ,micrococcus4 ,sidenote3 ,,fossil ,,bacteria4 ,it is unnecessary to give an account of the numerous examples of ,micrococci and ,bacilli described by ,renault from ,devonian1 ,carboniferous1 ,permian and ,jurassic rocks4 ,we may1 however1 in a few words consider the general question of the existence and possible determination of fossil ,bacteria4 ,in #ahgg ,prof4 ,van ,tieghem#bah of ,paris drew attention to the method of operation and plan of attack of ,bacillus amylobacter as a destructive agent in the decay of plant dbris in water4 ,he was able to follow the gradual disorganisation of the tissues and the various steps in the #8butyric fermentation' effected by this ,bacterium4 ,similarly the same author#bai was able to detect the action of an allied organism in some silicified tissues from the ,carboniferous nodules of ,grand-,croix1 a well-known locality for petrified plants near ,saint-tienne4 ,he recognised also the traces of the ,bacillus itself in the partially destroyed plant tissues4 ,the ,palaeozoic ,bacteria made use of some cellulose-dissolving ferment of which the action is clearly demonstrated in sections of silicified tissues4 ,many of the phenomena described by ,renault and ,bertrand as due to similar ,bacterial action1 afford additional evidence that the gradual disorganisation of vegetable tissues was effected in precisely the same manner as at the present day4 ,in some cases we have ,i believe trustworthy examples of the ,bacteria themselves1 both in coprolites and plant-tissues1 but it is more than probable that some of the recorded examples are not of any scientific value4 ,the examination of petrified tissues under the higher powers of a microscope often reveals the existence of numerous spherical particles and rod-like bodies which agree in shape with ,micrococci or ,bacilli4 ,minute crystals of mineral substances may occur in the siliceous or calcareous matrix of a petrified plant which simulate minute organic forms4 ,vogelsang#bbj in his important work die ,krystalliten has thrown considerable light on the ontogeny of crystals1 and the minute globulites and other forms of incipient crystallisation might well be mistaken for ,bacterial cells4 ,granting1 however1 that we have satisfactory evidence1 both direct and indirect1 that some forms of ,bacteria lived in the decaying tissues of ,palaeozoic plants1 and in the intestines of reptiles and other animals1 we cannot safely proceed to specific diagnoses and determinations#bba4 ,renault has pointed out that fossil ,bacteria may often be more readily detected than living forms owing to the presence of a brown ulmic substance which results from the carbonisation of the protoplasm4 ,he is forced to admit1 however1 that such diagnostic characters as are obtained by ,bacteriologists by means of cultures cannot be utilised when we are dealing with fossil examples6 ,we are told that 8,partout o nous avons cherch des ,bacteriaces1 nous en avons rencontr40#bbb ,this indeed is the danger2 an extended examination of fossil sections under an immersion-lens must almost inevitably lead to the discovery of minute bodies of a more or less spherical form which might be ,micrococci4 ,to measure1 and name such bodies as definite species of ,micrococci is1 ,i believe1 but wasted energy and an attempt to compass the impossible4 ,specialists tell us that the accurate determination of species of recent ,bacteria is practically hopeless3 may we not reasonably conclude that the attempt to specifically diagnose fossil forms is absolutely hopeless8 8,the imagination of man is naturally sublime1 delighted with whatever is remote and extraordinary--01 but it is to be deplored if the fascination of fossil bacteriology is allowed to warp sound scientific sense4 ,,iv4 ,,algae4 ,a4 ,,diatomaceae4 7,diatoms47 ,b4 ,,chlorophyceae4 7,green algae47 ,c4 ,,rhodophyceae4 7,red algae47 ,d4 ,,phaeophyceae4 7,brown algae47 ,the presence of chlorophyll is one common characteristic of the numerous plants included in the ,algae4 ,the generally adopted classification rests in part on an artificial distinction1 namely the prevailing colour of the plant4 ,it must be definitely admitted1 at the outset1 that palaeobotany has so far afforded extremely little trustworthy information as to the past history of algae4 ,were we to measure the importance of the geological history of these plants by the number of recorded fossil species1 we should arrive at a totally wrong and misleading estimate4 ,by far the greater number of the supposed fossil algae have no claim to be regarded as authentic records of this class of ,thallophytes4 ,it has been justly said that palaeontologists have been in the habit of referring to algae such impressions or markings on rocks as cannot well be included in any other group4 8,a fossil alga10 has often been the dernier ressort of the doubtful student4 ,sidenote3 ,,large ,,seaweeds4 ,before discussing our knowledge1 or rather lack of knowledge1 of fossil algae at greater length1 it will be well to briefly consider the manner of occurrence and botanical nature of existing forms4 ,in the sea and in fresh water1 as well as in damp places and even in situations subject to periods of drought1 algae occur in abundance in all parts of the world4 ,we find them attaining full development and reproducing themselves at a temperature of #a ,c4 in the ,arctic ,seas1 and again living in enormous numbers in the waters of thermal springs4 ,around the coast-line of land areas1 and on the floor of shallow seas algae exhibit a remarkable wealth of form and luxuriance of growth4 ,as regards habit and structure1 there is every gradation from algae in which the whole individual consists of a thin-walled unseptate vesicle1 to those in which the thallus attains a length unsurpassed by any other plant1 and of which the anatomical features clearly express a well-marked physiological division of labour such as occurs in the highest plants4 ,the large and leathery seaweeds which flourish in the extreme northern and southern seas are plants which it is reasonable to suppose might well have left traces of their existence in ancient sediments4 ,sir ,joseph ,hooker1 in his account of the ,antarctic flora#bbc1 investigated during ,sir ,james ,ross's voyage in ,h4,m4 ships ,erebus and ,terror1 has given an exceedingly interesting description of the gigantic brown seaweeds of southern latitudes4 ,the trunks are described as usually #e-aj feet long1 and as thick as a human thigh1 dividing towards the summit into numerous pendulous branches which are again broken up into sprays with linear #8leaves4' ,hooker records how a captain of a brig employed his crew for two bitterly cold days in collecting ,lessonia stems which had been washed up on the beach1 thinking they were trunks of trees fit for burning4 ,on our own coasts we are familiar with the common ,laminaria1 the large brown seaweed with long and strap-shaped or digitate fronds which grows on the rocks below low-tide level4 ,the frond passes downwards into a thick and tough stipe firmly attached to the ground by special holdfasts4 ,a transverse section of the stalk of a fairly old plant presents an appearance not unlike that of a section of a woody plant4 ,in the centre there is a well-defined axial region or pith consisting of thick walled1 long and narrow tubes pursuing a generally vertical though irregular course1 and embedded in a matrix of gelatinous substance derived from the mucilaginous degeneration of the outer portions of the cell-walls4 ,the greater part of such a section consists1 however1 of regularly disposed rows of cells which have obviously been formed by the activity of a zone of dividing or meristematic elements4 ,the occurrence of distinct concentric rings in this secondary tissue clearly points to some periodicity of growth which is expressed by the alternation of narrow and broader cells4 ,in the ,antarctic genus ,lessonia1 the stem reaches a girth equal to that of a man's thigh1 and in structure it agrees closely with the smaller stem of ,laminaria4 ,in these large algal stems1 the cells are not lignified as in woody plants1 and in longitudinal section they have for the most part the form of somewhat elongated parenchyma1 differing widely in appearance from the tracheids or vessels of woody plants4 ,at the periphery of the ,laminaria stem1 represented in fig4 #bi1 there occur numerous and comparatively large mucilage ducts4 ,illustration3 ,,fig4 #bi4 ,a1 ,transverse section of the stipe of a ,laminaria1 slightly enlarged4 ,b1 ,a small piece of the tissue between the central #8pith' and #8cortex' showing the radially disposed secondary elements more highly magnified4 ,in certain algae of different families the thallus is encrusted with carbonate of lime1 and is thus rendered much more resistant4 ,the ,diatoms1 on the other hand1 possess still more durable siliceous tests which are particularly well adapted to resist the solvent action of water and other agents of destruction4 ,it is these calcareous and siliceous forms which supply the greater part of the trustworthy data furnished by fossil algae4 ,sidenote3 ,,scarcity ,,of ,,fossil ,,algae4 ,it remains to consider some of the causes to which we may attribute the scarcity of fossil algae1 and the possible sources of error which beset any attempt to describe or assign names to impressions and casts simulating algal forms4 ,in the first place1 the delicate nature of algal cells is a serious obstacle to fossilisation4 ,even in plants in which the woody stems have been preserved by a siliceous or calcareous solution1 we frequently find the more delicate cells represented by a mass of crystalline matter without any trace of the cell-walls being preserved4 ,in such plants as algae1 where the cell-walls are not lignified1 but consist of cellulose or some special form of cellulose1 which readily breaks down into a mucilaginous product1 the tissues have but a small chance of withstanding the wear and tear of fossilisation4 ,the danger of relying on external form as a means of recognition is especially patent in the case of those numerous markings or impressions frequently met with on rocks1 and which resemble in outline the thallus of recent algae4 ,among animals1 such as certain ,polyzoa1 the flat branching body of various algae is closely simulated1 and in other plants1 such as the frondose liverworts1 the same thalloid and branched form of body is again met with4 ,some of the much dissected ,aphlebia leaves of ferns 7e4g4 ,rhacophyllum species7 bear a striking resemblance to fossil algae2 and numerous other examples might be quoted4 ,in palaeobotanical literature we find a host of names1 such as ,chondrites1 ,fucoides#bbd1 ,caulerpites and others applied to indefinite and indistinct surface markings which happen to resemble in shape certain of the better known genera of recent seaweeds4 ,the close parallelism in outward form displayed by different genera and families of algae is in itself sufficient argument against the use of recent generic names for fossils of which the algal nature is often more than doubtful4 ,were external form to be accepted as a trustworthy guide1 in the absence of internal structure and reproductive organs1 such a genus as ,caulerpa#bbe would afford material for numerous generic designations4 ,a comparison of the different species of this ,siphoneous green alga brings out very clearly the exceedingly protean nature of this interesting genus1 and serves as one instance among many of the small taxonomic value which can be attached to external configuration4 ,caulerpa pusilla ,mart4 and ,her41 ,c4 taxifolia 7,vahl471 ,c4 plumaris ,forsk41 ,c4 abies-marina ,j4 ,ag41 ,c4 ericifolia 7,turn471 ,c4 hypnoides 7,r4 ,br471 ,c4 cactoides 7,turn471 ,c4 scalpelli formis 7,r4 ,br471 and others clearly illustrate the almost endless variety of form exhibited by the species of a single genus of algae4 ,we constantly find in the several classes of plants a repetition of the same form either in the whole or in the separate members of the vegetative body1 and but a slight acquaintance with plant types should lead us to use the test of external resemblance with the greatest possible caution4 ,to emphasize this danger may seem merely the needless reiteration of a self-evident fact1 but there is1 perhaps1 no source of error which has been more responsible for the creation of numerous worthless species among fossil plants4 ,illustration3 ,,fig4 #cj4 #a4 ,rill-mark 7after ,williamson74 #b4 ,trail made by a seaweed dragged along a soft plaster of ,paris surface 7after ,nathorst74 #c4 ,tracks made by ,goniada maculata1 a ,polychaet 7after ,nathorst74 #d4 ,burrow of an insect4 #d;a4 ,section of the gallery 7after ,zeiller74 ,there is1 however1 another category of impressions and casts of common occurrence in sedimentary rocks which requires a brief notice4 ,very many of the fossil algae described in text-books and palaeobotanical memoirs have been shown to be of animal origin1 and to be merely the casts of tracks and burrows4 ,a few examples will best serve to illustrate the identity of many of the fossils referred to algae with animal trails and with impressions produced by inorganic agency4 ,dr ,nathorst of ,stockholm has done more than any other worker to demonstrate the true nature of many of the species of ,chondrites1 ,cruziana1 ,spirophyton1 ,eophyton1 and numerous other genera4 ,in #ahfg there were discovered in certain ,cambrian beds of ,vestrogothia1 long convex and furrowed structures in sandstone rocks which were described as the remains of some comparatively highly organised plant1 and described under the generic name ,eophyton#bbf4 ,by many authors these fossils have been referred to algae1 but ,nathorst has shown that the frond of an alga trailed along the surface of soft plaster of ,paris produces a finely furrowed groove 7fig4 #cj1 #b7 which would afford a cast similar to that of ,eophyton4 ,the same author has also adduced good reasons for believing that the ,eophytons of ,cambrian rocks may represent the trails made by the tentacles of a ,medusa having a habit similar to that of ,polydonia frondosa ,ag4 ,impressions of ,medusae have been described by ,nathorst from the beds in which ,eophyton occurs2 and the specimens in the ,stockholm ,museum afford a remarkable instance of the rare preservation of a soft-bodied organism#bbg4 ,by allowing various animals to crawl over a soft-prepared surface it is possible to obtain moulds and casts which suggest in a striking manner the branched thallus of an alga4 ,the tracks of the ,polychaet1 ,goniada maculata rstd4#bbh1 one of the ,glyceridae1 are always branched and very algal-like in form 7fig4 #cj1 #c74 ,many of the so-called fossil algae are undoubtedly mere tracks or trails of this type4 ,in the fossil-plant gallery of the ,british ,museum there are several specimens of small branched casts1 clearly marked as whitish fossils on a dark grey rock of ,lower ,eocene age from ,bognor2 these were described by ,mantell and ,brongniart#bbi as an alga1 but there is little doubt of their being of the same category as the track shown in fig4 #cj1 #c4 ,sidenote3 ,,fossils ,,simulating ,,algae4 ,the well-known half-relief casts met with in ,cambrian1 ,silurian and ,carboniferous rocks1 and known as ,cruziana or ,bilobites1 are probably casts of the tracks of ,crustaceans4 ,the impression left by a ,king-,crab 7,limulus7 as it walks over a soft surface affords an example of this form of cast4 ,it has been suggested that some of the ,bilobites may be the casts of an organism like ,balanoglossus#bcj1 a worm-like animal supposed by some to have vertebrate affinities4 ,the resemblance between some of the lower ,palaeozoic ,bilobites and the external features of a ,balanoglossus is very striking1 and such a comparison is worth considering in view of the fact that soft-bodied animals have occasionally left distinct impressions on ancient sediments4 ,the literature on the subject of fossil algae versus inorganic and animal markings is too extensive and too wearisome to consider in a short summary2 the student will find a sufficient amount of such controversial writing--with references to more--in the works quoted below#bca4 ,in the ,stockholm ,museum of ,palaeobotany there is an exceedingly interesting collection of plaster casts obtained by ,dr ,nathorst in his experiments on the manufacture of fossil #8algae1' which afford convincing proof of the value and correctness of his general conclusions4 ,the pressure of the hand on a soft moist surface produces a raised pattern like a branched and delicate thallus4 ,the well-known ,oldhamia antiqua ,forbes and ,oldhamia radiata ,forbes#bcb1 from the ,cambrian rocks of ,ireland may1 in part at least1 owe their origin to mechanical causes1 and we have no sufficient evidence for including them among the select class of true fossil algae4 ,sollas#bcc has shown that the structure known as ,oldhamia radiata is not merely superficial but that it extends across the cleavage-planes4 ,oldhamia is recorded from ,lower ,palaeozoic rocks in the ,pyrenees#bcd by ,barrois1 who agrees with ,salter1 ,gppert and others in classing the fossil among the algae4 ,the photograph accompanying ,barrois' description does not1 however1 add further evidence in favour of accepting ,oldhamia as a genus of fossil algae4 ,the burrows made by ,gryllotalpa vulgaris ,latr41 the ,mole-cricket1 have been shown by ,zeiller to bear a close resemblance to a branch of a conifer in half-relief 7fig4 #cj1 #d71 or to such a supposed algal genus as ,phymatoderma#bce4 ,in fig4 #cj1 #a1 we have what might well be described as a fossil alga4 ,this is merely a cast of a miniature river-system such as one frequently sees cut out by the small rills of water flowing over a gently-sloping sandy beach4 ,a cast figured and described by ,newberry as an alga1 ,dendrophycus triassicus#bcf1 from the ,trias of the ,connecticut ,valley1 is practically identical with the rill-marks shown in fig4 #cj1 #a4 ,the cracks produced in drying and contracting sediment may form moulds in which casts are subsequently produced by the deposition of an overlying layer of sand1 and such casts have been erroneously referred to algal impressions#bcg4 ,dawson#bch has figured two good examples of ,carboniferous rill-marks from ,nova ,scotia in his paper on ,palaeozoic burrows and tracks of invertebrate animals4 ,sidenote3 ,,recognition ,,of ,,fossil ,,algae4 ,illustration3 ,,fig4 #ca4 ,chondrites verisimilis ,salt4 ,wenlock limestone1 ,dudley4 ,from a specimen in the ,british ,museum 7,v4 #beej74 ,slightly reduced4 ,the specimen represented in fig4 #ca affords an example of a fairly well-known fossil from the ,wenlock limestone1 originally described by ,salter as ,chondrites verisimilis ,salt1 from ,dudley#bci4 ,he regarded it as an alga1 and the graphitic impression agrees closely in form with the thallus of some small seaweeds4 ,a closer examination of the fossil reveals a curious and characteristic irregular wrinkling on the graphite surface1 which suggests an organism of more chitinous and firmer material than that of an alga4 ,a similar and probably an identical fossil is described and figured by ,lapworth#bdj in an appendix to a paper by ,walter ,keeping on the geology of ,central ,wales1 under the name of ,odontocaulis ,keepingi ,lap4 and regarded as a dendroid graptolite4 ,in any case we have no satisfactory grounds for including these fossils in the plant-kingdom4 ,how then are we to recognise the traces of ancient algae8 ,there is no golden rule1 and we must admit the difficulty of separating real fossil algae from markings made by animal or mechanical agency4 ,the presence of a carbonaceous film is occasionally a help1 but its occurrence is no sure test of plant origin1 nor is its absence a fatal objection to an organic origin4 ,while being fully alive to the small value of external resemblance1 and to the numerous agents which have been shown to be capable of producing appearances indistinguishable from plant impressions1 we must not go too far in a purely negative direction4 ,an important contribution to the subject of fossil algae has lately appeared by ,prof4 ,rothpletz#bda4 ,he deals more particularly with the much discussed ,flysch#bdb ,fucoids of ,tertiary age1 and while refusing to accept certain examples as fossil algae1 he brings forward weighty arguments in favour of including several other forms among the algae4 ,he is of opinion that most of the main divisions of the algae are represented among the ,flysch ,fucoids1 but considers that the ,phaeophyceae are the most numerous4 ,rothpletz's work is chiefly interesting as illustrating the application of microscopic examination and chemical analysis to the determination of fossil algae4 ,although he makes out a good case in favour of restoring many of the ,tertiary fossils to the plant kingdom1 the material at his disposal does not admit of satisfactory botanical diagnosis4 ,no doubt some of the fossils from the ,silurian and ,cambrian rocks are true algae1 and ,nathorst has pointed out that such a species as ,hall's ,sphenothallus angustifolius#bdc may well be an alga4 ,additional examples might be quoted from ,bornemann and other writers1 but in view of the attempts which are sometimes made to trace the development of more recent plants to more than doubtful ,lower ,palaeozoic ,algae1 one must agree with ,nathorst's opinion1--8,je crois que l'on rend un bien mauvais service la thorie de l'volution1 en essayant de baser l'arbre gnalogique des algues fossiles sur des corps aussi douteux que les ,bilobites1 ,crossochorda1 ,eophyton1 etc4#bdd0 ,there are many carbonaceous impressions on rocks of different ages which it is reasonable to refer to algal origin1 and although such are of little or no botanical value1 it may be a convenience to refer to them under a definite term4 ,the comprehensive generic name ,algites#bde has been suggested as a convenient designation for impressions or casts which are probably those of algae4 ,sidenote3 ,,supposed ,,fossil ,,algae4 ,some of the fossils described by ,mr ,kidston from ,british ,carboniferous rocks as probably algae present an undoubted algal appearance1 and might be placed in the genus ,algites2 but in some cases--e4g4 ,chondrites plumosa#bdf ,kidst4 from the ,calciferous ,sandstone of ,eskdale1 one feels much more doubtful2 in this particular instance the impressions suggest the fine roots of a water-plant4 ,the statement is occasionally made that the numerous fossil algae and the absence of higher plants in the older strata justify the description of the oldest rocks as belonging to the #8age of algae4' ,such an assertion rests on an unsound basis1 and is rather the expression of what might be expected than what has been proved to be the case4 ,the oldest plants with which we are at all closely acquainted are of such a type as to forcibly suggest that in the lowest fossiliferous rocks we are still very far from the sediments of that age which witnessed the dawn of plant life4 ,many of the obscure markings on rock surfaces which have been referred to existing genera of algae or described as new genera1 are much too doubtful to be included even under such a comprehensive name as ,algites4 ,space does not admit of further reference to determinations of this type which abound in palaeontological literature4 ,it would be very difficult to produce satisfactory evidence for the algal nature of many of the supposed fossil algae from ,cambrian rocks#bdg2 there has been a special tendency to recognise algal remains in the oldest fossiliferous strata1 due in part no doubt to the fallacy that in that period nothing higher than ,thallophytes is likely to have existed4 ,the so-called ,phycodes referred to by ,credner#bdh as characteristic of the ,cambrian rocks of the ,fichtelgebirge 78,phycoden-,schiefer07 is probably of inorganic origin1 and comparable to the genus ,vexillum of ,saporta#bdi and other writers1 which ,solms-,laubach has described as being formed every day in the soft mud of our ponds where local currents are checked by branches and other obstacles#bej4 ,there are several good specimens of ,phycodes in the ,bergakademie of ,berlin and in the ,leipzig ,museum which1 ,i believe1 clearly demonstrate the absence of all satisfactory evidence of an algal origin4 ,we may next pass to a short description of a few representative types of algae1 which may reasonably be classed under definite families1 and accepted as evidence possessing some botanical value4 ,a4 ,,diatomaceae 7,,bacillariaceae74 ,this family occupies a somewhat isolated position among the algae1 and is best considered as a distinct subdivision rather than as a family of the ,phaeophyceae or ,brown algae1 with which it possesses as a common characteristic a brown-colouring matter4 ,single-celled plants consisting of a simple protoplasmic body containing a nucleus and brown colouring matter 7diatomin7 associated with the chlorophyll4 ,the cell-wall is in the form of two halves1 known as valves1 which fit into one another like the two portions of a pill-box4 ,the cell-wall contains a large amount of silica1 and the siliceous cases of the diatoms are commonly spoken of as the valves of the individual1 or the frustules4 ,diatoms exhibit a characteristic creeping movement1 and are reproduced by division1 also by the development of spores in various forms#bea4 ,the recent members of the family have an exceedingly wide distribution1 occurring both in freshwater and in the sea4 ,owing to the lightness of the frustules1 they are frequently carried along in the air1 and atmospheric dust falling on ships at sea has been found to contain large numbers of diatoms#beb4 ,the siliceous valves are abundant in guano deposits1 and they have been found also in association with volcanic material4 ,diatomaceous deposits are now being formed in the ,yellowstone ,park district2 8they cover many square miles in the vicinity of active or extinct hot spring vents of the park1 and are often three feet1 four feet1 and sometimes five to six feet thick#bec40 ,the gradual accumulation of the siliceous tests on the floor of a fresh-water lake results in the formation of a sediment consisting in part of pure silica4 ,such deposits1 often spoken of as kieselguhr or diatomite1 and used as a polishing material1 occur in many parts of ,britain1 marking the sites of dried-up pools or lakes4 ,at the northern end of the island of ,skye there occurs an unusually pure deposit of diatomite overlain by peat and turf1 and extending over an area of fifty-eight square miles4 ,many of the individuals in this deposit were in all probability carried into the lake by running water1 while others lived in the lake and after death their tests contributed to the siliceous deposit#bed4 ,the late ,dr ,ehrenberg published numerous papers on diatomaceous deposits in different parts of the world1 and in his great work1 ,zur ,mikrogeologie#bee1 he gave numerous and beautifully executed illustrations of such siliceous accumulations4 ,in many of the samples he figures one sees fragments of plant tissues1 spores of conifers and ferns1 associated with the diatom tests4 ,the occurrence of the pollen grains of coniferous trees in lacustrine and marine deposits is not surprising in view of their abundance in ,lake ,constance and other lakes4 ,it is stated that the pollen of conifers in the ,norwegian fiords plays an important part in the nourishment of the ,rhizopod ,saccamina#bef4 ,sidenote3 ,,diatomaceous ,,ooze4 ,in the waters of the ocean diatoms are of frequent occurrence1 and very widely distributed4 ,sir ,joseph ,hooker records the existence of masses of diatomaceous ooze over a wide area in ,antarctic regions#beg4 ,along the shores of the ,victoria ,barrier1 a perpendicular wall of ice1 between one and two hundred feet above sea-level1 the soundings were found to be invariably charged with diatom remains1 and from the base of the ice-wall there appeared to be in process of formation a bank of these tests stretching north for a distance of #bjj miles4 ,the more extended researches conducted during the cruise of the ,challenger have clearly proved the enormous accumulations of diatoms now being formed on the ocean-bed#beh4 ,south of latitude #de ,s4 there is now being built up a vast deposit which may be eventually upraised as a fairly pure siliceous rock4 ,from extreme northern latitudes ,nansen has recently recorded the occurrence of these lowly organised plants4 ,he writes1--8,i found a whole world of diatoms and other microscopical organisms1 both vegetable and animal1 living in the fresh-water pools on the ,polar drift-ice1 and constantly travelling from ,siberia to the east coast of ,greenland#bei40 ,in warmer latitudes diatoms abound in the surface waters1 but there they are associated with numerous other forms of the ,plankton vegetation4 ,the waters of the ,amazon carry with them into the sea large numbers of fresh-water forms1 which are floated out to sea and finally added to the rock-building material which is constantly accumulating on the ocean floor#bfj4 ,no definite results have so far been obtained as to the geographical and bathymetrical distribution of marine diatoms4 ,the enormous number of recent species precludes any attempt to give a description of the better-known forms4 ,it is more important for us to realize how common and widely distributed are the living genera4 ,the hard and almost indestructible valves have been frequently found in a fossil condition1 often forming thick and extensive masses of siliceous rock4 ,from diatom-beds now forming in lakes and on the ocean-bed we pass to deposits such as those in ,skye and elsewhere1 which mark the site of recently dried-up sheets of water1 and so to older rocks of ,tertiary age formed under similar conditions4 ,among the many examples of diatomaceous deposits of ,tertiary and ,cretaceous age mention should be made of those of ,berlin1 ,knigsberg1 ,bilin in ,bohemia1 and ,richmond in ,virginia4 ,the diatoms in the beds of ,berlin are regarded as fresh-water1 and those of ,richmond as marine4 ,it has been pointed out by ,pfitzer that it is a comparatively easy matter to distinguish between fresh-water and marine forms of diatoms4 ,the diatomaceous rocks of ,bilin are known as polishing slates2 they attain a thickness of #ej feet4 ,in these1 as in many other cases1 the deposit has become cemented together as a hard flinty or glassy rock1 in which the cementing material was formed by the solution of some of the diatom tests#bfa4 ,in many cases in which calcareous and siliceous rocks reveal no direct evidence of organic origin it is probable that they were originally formed by the accumulation of plants of which the structure has been completely obliterated by secondary causes4 ,the genus ,gallionella plays an important part in the composition of the ,bilin beds4 ,occasionally impressions of leaves and other organic remains are found associated with the diatoms in the siliceous rocks4 ,in the ,british ,museum 7,botanical department7 a large block of white powdery rock is exhibited as an example of a diatomaceous deposit of ,tertiary age from ,australia4 ,it is described as being largely made up of the tests of fresh-water diatoms1 such as ,navicula1 ,gomphonema1 ,cymbella1 ,synedra1 and others4 ,sidenote3 ,,fossil ,,diatoms4 ,the abundance of ,diatoms in ,cretaceous rocks of the ,paris basin has recently been recorded by ,cayeux#bfb2 it would seem that these algae had already assumed an important rle as rock-builders in pre-,tertiary times4 ,cayeux points out that the silica of these ,cretaceous diatomaceous frustules has often been replaced by carbonate of calcium4 ,in addition to the occurrence of ,diatoms in the various diatomaceous deposits1 their siliceous tests may occasionally be recognised in argillaceous or other sediments4 ,shrubsole and ,kitton#bfc have described several species of ,diatoms from the ,london ,clay of ,lower ,eocene age4 ,in many localities in the ,london basin the clay obtained from well-sinkings presented the appearance of being dusted with sulphur-like particles of a dark bronze or golden colour which glistened in the sunlight4 ,these yellow bodies have been found to be diatomaceous frustules in which the silica has been replaced by iron pyrites4 ,the genus ,coscinodiscus is one of the commonest forms recorded from the ,london ,clay#bfd4 ,without further considering individual examples of diatomaceous rocks we may briefly notice the general facts of the geological history of the family4 ,as ,ehrenberg pointed out several years ago1 the ,tertiary and ,cretaceous species of diatoms show a very marked resemblance to living forms4 ,in many cases the species are identical1 and the fossil deposits as a whole seem to differ in no special respect from those now being built up4 ,with the exception of two species of ,liassic ,diatoms1 no trustworthy examples of the ,diatomaceae have been found below the ,cretaceous series4 ,the oldest known ,diatoms were discovered by ,rothpletz#bfe among the fibres of an ,upper ,lias sponge from ,boll in ,wrttemberg4 ,they occur as small thimble-shaped siliceous tests with coccoliths and foraminifera in the horny skeleton of ,phymatoderma1 a genus formerly regarded as an alga4 ,rothpletz describes two species which he includes in the genus ,pyxidicula1 ,p4 bollensis and ,p4 liasica4 ,this generic name of ,ehrenberg is used by ,schtt#bff as a subgenus of ,stephanopyxis4 ,seeing how great a resemblance there is between the recent and ,cretaceous species1 and how many examples there are of ,tertiary diatom deposits1 it is not a little surprising that the past history of these plants has not been traced to earlier periods4 ,in #ahgf ,castracane#bfg1 an ,italian diatomist1 gave an account of certain species of diatoms said to have been found in a block of coal from ,liverpool obtained from the ,english ,coal-,measures4 ,the species were found to be identical with recent forms4 ,it is generally agreed that these specimens cannot have been from the coal itself1 but that they must have been living forms which had come to be associated with the coal4 ,the late ,prof4 ,williamson spent many years examining thin sections and other preparations of coal from various parts of the world1 but he never found a trace of any fossil diatom4 ,there is no apparent reason why diatoms should not be found in ,pre-,cretaceous rocks1 and the microscopic investigation of old sediments may well lead to their discovery4 ,prof4 ,bertrand of ,lille1 who has devoted himself for some time past to a detailed microscopical examination of coal1 informs me that he has so far failed to discover any trace of ,palaeozoic diatomaceous tests4 ,sidenote3 ,,bactryllium4 ,the genus ,bactryllium is often quoted in text-books as a probable example of a ,triassic diatom4 ,it was first described by ,heer#bfh from the ,trias of ,switzerland and ,north ,italy1 also from the neighbourhood of ,heidelberg1 and regarded as an extinct member of the ,diatomaceae4 ,heer defined the genus as follows3 8,small bodies1 with parallel sides1 rounded at either end1 the surface traversed by one or two longitudinal grooves40 7fig4 #cb1 ,c47 ,several species have been figured by ,heer from beds of ,muschelkalk1 ,keuper and ,rhaetic age4 ,he describes the wall as thick and firm 7fig4 #cb1 ,c4 ii47 and probably composed of silica1 with a hollow interior4 ,the specimen shown in fig4 #cb1 ,c4 was found in the ,rhaetic beds1 and named by ,heer ,bactryllium deplanatum2 it has a length of #de mm42 the surface is transversely striated and traversed by a single longitudinal groove4 ,stefani#bfi has given reasons in favour of removing ,bactryllium from the plant to the animal kingdom2 he points out that the specimens are too large for diatoms1 and moreover that they are asymmetrical in form and possessed a calcareous and not a siliceous shell4 ,he would place the fossil among the ,pteropods1 comparing it with such genera as ,cuvierina and ,hyalaea4 ,in view of ,stefani's opinion we cannot attach any importance to this supposed diatom1 especially as it has generally been regarded as at best but an unsatisfactory genus4 ,illustration3 ,,fig4 #cb4 ,a1 ,lithothamnion mamillosum ,gmb4 7i7 ,in section1 7ii7 surface view after ,gmbel4 7i7 #cbj1 7ii7 nat4 size4 ,b1 ,sycidium melo ,sandb4 7i7 ,surface view1 7ii7 transverse section 7after ,deecke74 ,c1 ,bactryllium deplanatum ,heer4 7i7 ,surface view1 7ii7 section1 showing the thick wall and hollow interior 7after ,heer74 ,d1 ,calcareous pebble from a lake in ,michigan4 ,rather less than nat4 size 7after ,murray74 ,b4 ,,chlorophyceae 7,,green ,,algae74 ,thallus unseptate1 having the form of a vesicle or a variously branched coenocyte1 which may or may not be encrusted with carbonate of lime1 or of filaments composed of cells containing a single nucleus1 or of cells in which more than one nucleus occurs2 in other instances consisting of a plate of cells or a cell-mass4 ,asexual reproduction by zoospores and other reproductive cells2 sexual reproduction by means of the conjugation of similar gametes or by the fertilisation of a typical egg-cell by a motile spermatozoid4 ,this family of algae is represented at the present day by numerous and widely distributed marine and fresh-water genera1 as well as by genera growing in moist air or as endophytes in the tissues of higher plants#bgj4 ,seeing how very few fossil forms have been described which have any claim to inclusion in this subdivision of the ,algae1 it is unnecessary to enumerate or define the various families of the ,chlorophyceae4 ,it is true that many species have been figured as examples of different genera of green algae1 but few of these possess any scientific value4 ,there is1 however1 one division of the ,chlorophyceae1 the ,siphoneae1 which must be treated at some length on account of its importance from a palaeobotanical and geological point of view4 a4 ,,siphoneae4 ,thallus consisting of simple or branched cells very rarely divided by septa1 and containing many nuclei4 ,in certain genera the branches form a pseudoparenchymatous tissue by their repeated branching1 and as a result of the intimate felting together of the branched cells4 ,reproduction is effected either by the conjugation of similar gametes or by the fertilisation of an egg-cell4 ,vaucheria and ,botrydium are two well-known ,british genera of this order1 but most of the recent representatives live in tropical and subtropical seas4 ,the most striking characteristic feature of this division of the ,chlorophyceae is the fact that the thallus of a siphoneous alga consists of an unseptate coenocyte2 the plant may be extremely small and simple1 or it may reach a length of several inches1 but in all cases the body does not consist of more than one cell or coenocyte4 ,from a palaeontological standpoint the ,siphoneae are of exceptional interest4 ,it is impossible to do more than refer to a few of the living and fossil genera4 ,there are numerous fossil representatives already known1 and there can be little doubt that further research would be productive of valuable results4 ,as examples of the order1 a few genera may be described belonging to the three families ,caulerpaceae1 ,codiaceae1 and ,dasycladaceae4 4 ,caulerpaceae4 ,thallus unseptate1 showing an extraordinary variation in the external differentiation of the plant-body4 ,reproduction is effected by means of detached portions of the parent plant4 ,the genus ,caulerpa1 represented by a few species in the ,mediterranean and by many tropical forms1 has already been alluded to as a striking example of a plant which appears under a great many different forms#bga4 ,as a recent writer has said1 8,nature seems to have shown in this genus the utmost possibilities of the siphoneous thallus#bgb10 ,fragments of coniferous twigs1 the tracks and burrows of various animals and other objects have been described by several authors as fossil species of ,caulerpa4 ,as an illustration of the identification of a very doubtful fossil as a species of ,caulerpites1 reference may be made to such a form as ,c4 cactoides ,gpp4#bgc from ,silurian and ,cambrian rocks4 ,there are several examples of this fossil in the ,brussels ,museum which probably owe their origin to some burrowing animal1 and may be compared with ,zeiller's figures of the tunnels made by the mole-cricket 7fig4 #cj1 #d7bgd4 ,mr ,murray1 of the ,british ,museum1 has recently described what he regards as a trustworthy example of a fossil ,caulerpa from the ,kimeridge ,clay near ,weymouth#bge4 ,specimens of the fossil were first figured in a book on the geology of the ,dorset coast as casts of an equisetaceous plant#bgf4 ,to this fossil ,murray has assigned the name ,caulerpa ,carruthersi1 and given to it a scientific diagnosis4 ,the best specimens have the form of a slender central axis1 giving off at fairly regular intervals whorls of short and somewhat clavate branches2 they bear a superficial resemblance to such a recent species as ,caulerpa cactoides ,ag4 ,an examination of several examples of this fossil leads me to express the opinion that there is not sufficient reason for assigning to them the name of a recent genus of algae#bgg4 ,to use the generic name of a recent plant without following the common custom of adding on the termination 8ites0 7i4e4 ,caulerpites7 is as a general rule to be avoided in dealing with fossil forms2 and there are1 ,i believe1 no satisfactory grounds for referring to these fossils as trustworthy examples of a ,mesozoic alga4 ,in the present case ,i am disposed to regard the ,caulerpa-like casts as of animal rather than plant origin4 ,the clavate branches have the form of very deep moulds in the hard brown rock which have been filled in with blue mud4 ,it is hardly conceivable that the branches of a soft watery plant such as ,caulerpa could leave more than a faint impression on an old sea-floor4 ,the specimens occur in different positions in the matrix of the rock and they are not confined to the lines of bedding2 in none of the examples is there any trace of carbonaceous matter in association with the deep moulds4 ,on the whole1 then1 this ,kimeridge fossil cannot1 ,i believe1 be accepted as an authentic example of a ,mesozoic ,caulerpa4 ,it is not improbable that some of the supposed fossil algae may be casts of egg-cases or spawn-clusters of animals4 ,in ,ellis' ,natural ,history of the ,corallines#bgh there is a drawing representing a number of disc-like ovaries attached to a tough ligament1 and referred to the mollusc ,buccinum1 which bears a certain resemblance to the ,weymouth fossil4 ,a similar body is figured by ,fuchs#bgi in an important memoir on supposed fossil algae4 ,it is not suggested that the ,caulerpa ,carruthersi of ,murray should be regarded as the cast of some molluscan egg-case attached to a slender axis1 but it is important to bear in mind the possibility of matching such extremely doubtful fossils with other organic bodies than the thallus of a ,caulerpa4 ,in an example of an egg-case in the ,cambridge ,zoological ,museum1 referred to a species of ,pyrula1 there is a hard1 long and slender axis1 bearing a series of semicircular chambers divided into radial compartments4 ,the whole is hard and horny and might well be preserved as a fossil4 4 ,codiaceae4 ,the members of this ,order present a considerable diversity of form as regards the shape of the plant-body2 the thallus of some species is encrusted with carbonate of lime4 ,the order is widely distributed in tropical and temperate seas4 ,among the recent genera ,penicillus and ,codium may be chosen as important types from the point of view of fossil representatives4 ,codium4 ,the thallus of ,codium consists of a spongy mass of tubular cell-branches which are differentiated into two fairly distinct regions1 an outer peripheral layer in which the branches have long club-shaped terminations1 and an inner region consisting of loosely interwoven filaments4 ,codium ,bursa ,l4 and ,c4 tomentosum ,huds4 are two well-known ,british species1 the former presents the appearance of a spongy ball of cells1 and in the latter the thallus is divided up into dichotomously forked branches#bhj4 ,in this genus the thallus is not encrusted with carbonate of lime1 at least in recent species4 ,sphaerocodium4 ,fig4 #cg1 ,d4 ,rothpletz#bha instituted this genus for certain small spherical or oval bodies varying from #a mm4 to #b cm4 in diameter1 which have been found on crinoid stems or shell fragments of ,triassic age4 ,each spherical body consists of dichotomously branched single-celled filaments1 between #ej and #ajj in breadth1 and from #cjj-ejj in height4 ,the tubular cavities occasionally swell out into spherical spaces which are regarded by ,rothpletz as sporangia4 ,there is not sufficient evidence that ,sphaerocodium ,bornemanni ,roth4 has been correctly referred to the ,codiaceae4 ,the sporangia-like swellings described by the author of the species are not by any means conclusive as characters of important taxonomic value4 ,figure #cg1 ,d1 illustrates the general structure of the fossil as seen in a transverse section of one of the calcareous grains4 ,like ,girvanella1 which has been referred by some writers to the ,siphoneae1 ,sphaerocodium occurs in the form of oolitic grains4 ,in the ,triassic ,raibler and ,st ,cassian beds of the ,tyrol1 as well as in rocks of ,rhaetic age in the ,eastern ,alps1 it makes up large masses of limestone4 ,rothpletz compares the structure of this genus with that of the recent alga ,codium adhaerens ,ag41 but it is wiser to regard such tubular structures as ,girvanella1 ,siphonema#bhb and ,sphaerocodium as closely allied organisms1 which are probably algae1 but too imperfectly known to be referred to any particular family4 ,penicillus4 ,the recent genus ,penicillus is one of those algae formerly included among animals4 ,fig4 #cc1 ,o1 has been copied from a drawing of a species of ,penicillus given by ,lamouroux#bhc under the generic name of ,nesea in his treatise on the genera of ,polyps published in #ahba4 ,he describes the genus as a brush-like ,polyp with a simple stem4 ,the thallus consists of a stout stem terminating in a brush-like tuft of fine dichotomously-branched filaments4 ,the apical branches are divided by regular constrictions into short oval or rod-like segments which may be encrusted with carbonate of lime4 ,a few of the segments from the terminal tuft of a recent ,penicillus are shown in fig4 #ce1 ,e4 ,each of these calcareous segments has the form of an oval shell perforated at each end1 and the wall is pierced by numerous fine canals4 ,penicillus is represented by about #aj recent species1 which with one exception live in tropical seas4 ,the recognition of ,penicillus1 or a very similar type1 in a fossil condition is due to ,munier-,chalmas#bhd4 ,this keen observer has rendered great service to palaeobotany by directing attention to the calcareous algae in the ,paris basin beds1 and by proving that many of the fossils from these ,tertiary deposits have been erroneously included by previous writers among the ,foraminifera#bhe4 ,it is greatly to be desired that ,prof4 ,munier-,chalmas may soon publish a monograph on the fossil ,siphoneous forms of which he possesses a unique collection4 ,ovulites4 ,figs4 #cc1 ,k1 ,l1 and #ce1 ,f4 ,in his ,natural ,history of ,invertebrate ,animals1 ,lamarck described some small oval bodies from the ,calcaire ,grossier 7,eocene7 of the ,paris basin under the name of ,ovulites4 ,he defined them as follows3--8,polypier pierreux1 libre1 ovuliforme ou cylindrac1 creux intrieurement1 souvent perc aux deux bouts4 ,pores trs petits1 rgulirement disposs la surface#bhf40 ,illustration3 ,,fig4 #cc4 ,a and ,b1 ,cymopolia barbata 7,l472 ,a1 transverse section of the calcareous cylinder4 ,b1 verticillate branches and sporangium after removal of the calcareous matrix 7,a and ,b after ,munier-,chalmas74 ,c and ,d1 ,acicularia ,andrussowi ,solms 7,c1 after ,andrussowi2 ,d1 after ,solms74 ,e1 ,acicularia ,miocenica ,reuss2 section of a spicula 7after ,reuss74 ,f and ,g1 ,acicularia sp4 7after ,carpenter71 ,f #dj2 ,g #bj4 ,h1 ,acicularia ,schencki 7,mb47 7after ,solms74 ,i1 ,acetabularia ,mediterranea ,lamx42 section of the cap 7after ,falkenberg74 ,k and ,l1 ,ovulites margaritula 7,lam47 7after ,munier-,chalmas72 ,k slightly enlarged2 ,l1 a piece of the thallus more highly magnified4 ,m1 ,cymopolia barbata 7,l47 7after ,ellis1 nat4 size74 ,n1 ,c4 barbata 7,l472 the surface of the thallus2 magnified4 ,o1 ,penicillus pyramidalis 7,lamx47 7after ,lamouroux1 nat4 size74 ,the specimens are referred to two species1 ,ovulites margaritula and ,o4 elongata4 ,by some subsequent writers#bhg these calcareous fossils1 like miniature birds' eggs with a hole at either end1 were included among the ,zoophytes4 ,carpenter and others afterwards referred ,ovulites to the ,foraminifera1 and compared the genus with ,lagena#bhh4 ,the single specimens of ,ovulites have a length of #b-f mm4 ,at each end there is usually a fairly large and somewhat irregular hole 7fig4 #ce1 ,f71 and in some rarer cases there may be two apertures at the broader end of an ,ovulite4 ,a good example of ,ovulites margaritula with two pores at the broader end is figured by ,michelin#bhi4 ,the surface of the shell when seen under a low magnifying power appears to be covered over with regularly arranged circular pores1 which are the external openings of fine canals 7fig4 #cc1 ,l74 ,in #ahgh ,munier-,chalmas expressed the opinion1 which was supported by strong evidence1 that ,ovulites should be referred to the siphoneous algae#bij4 ,he regarded it as generically identical with ,penicillus 7,coralliodendron1 ,ktzing74 ,it has already been pointed out that in ,penicillus the apical tuft of filaments is partially calcareous 7fig4 #cc1 ,o7#bia4 ,the individual calcareous segments agree almost exactly with the fossil ,ovulites4 ,as a rule the ,ovulites occur as separate egg- or rod-like bodies1 but ,munier-,chalmas informs me that occasionally two or three have been found joined end to end in their natural position4 ,the terminal holes in the fossil specimens represent the apertures left after the detachment of the calcareous segments from the uncalcified filaments of the alga4 ,the segments with two holes at the broader end were no doubt situated at the base of dichotomising branches as shown in fig4 #cc1 ,k4 ,the restoration of ,ovulites1 shown in fig4 #cc1 ,k1 bears a striking resemblance to the figure of an ,australian ,penicillus given by ,harvey in his ,phycologia ,australica#bib4 ,it is probable that these ,eocene forms agreed closely in habit with the recent species of ,penicillus4 ,the portions preserved as fossils are segments of the filaments which probably formed a terminal brush of fine branches supported on a stem4 ,the retention of the original generic name ,ovulites is on the whole better than the inclusion of the fossil species in the recent genus4 ,the ,tertiary species lived in warm seas of the ,lower and ,middle ,eocene of ,england1 ,belgium1 ,france and ,italy4 ,halimeda4 ,an example of an ,eocene species of ,halimeda has been recorded by ,fuchs from ,greifenstein under the name of ,halimeda ,saportae#bic4 ,the impression has the form of a branched plant consisting of wedge-shaped or oval segments1 and there is a close resemblance to the thallus of a recent ,halimeda1 e4g4 ,h4 gracilis ,harv4 ,it is not improbable that ,fuchs' determination is correct1 but without more definite evidence than is afforded by a mere impression it is a little rash to make use of the recent generic name4 4 ,dasycladaceae4 ,in this family of ,siphoneae are included a number of genera represented by species living in tropical and subtropical seas4 ,the thallus consists of an elongated axial cell fixed to the substratum by basal rhizoids1 and bearing whorls of lateral appendages of limited growth which may be either simple or branched4 ,many of the lateral branches bear sporangia or spores4 ,the thallus is in many species encrusted with carbonate of lime4 ,the two genera ,acetabularia and ,cymopolia may be briefly described as recent types which are represented by trustworthy fossil forms4 ,illustration3 ,,fig4 #cd4 ,acetabularia mediterranea ,lamx4 ,from a specimen in the ,cambridge ,botanical ,museum 7nat4 size74 ,acetabularia4 ,figs4 #cc1 ,i1 and #cd4 ,with the exception of ,a4 mediterranea ,lamx4 7fig4 #cd7 the few living species of this genus are confined to tropical seas4 ,the habit of ,acetabularia is well illustrated by the photograph of a cluster of plants of ,a4 mediterranea ,lamx4#bid reproduced in fig4 #cd4 ,the thallus consists of a delicate stalk attached to the substratum by a tuft of basal holdfasts1 and expanded distally into a small circular disc #aj-ab mm4 in diameter and more or less concave above4 ,this terminal cap is made up of a number of laterally fused appendages given off from the upper part of the stalk in the form of a crowded whorl4 ,the whole thallus resembles a small and long-stalked calcareous fungus4 ,in each radially elongated compartment of the fertile cap 7fig4 #cc1 ,i7 there are several sporangia 7gametangia7 developed2 these eventually open and produce numerous ciliated gametes which give rise to zygospores by conjugation4 ,fig4 #cc1 ,i1 represents the cap of an ,acetabularia in radial section and surface-view2 the two radial compartments seen in section contain the elliptical gametangia2 the circular markings at the base of the figure are scars of sterile deciduous branches4 ,the whole plant is unicellular1 each chamber in the disc being in open communication with the stem of the plant4 ,acicularia4 ,fig4 #cc1 ,c-,h4 ,in a recent monograph on the ,acetabularieae1 ,solms-,laubach#bie has described a new type of these algae which is of special importance from the point of view of the past history of the family4 ,mbius described an example of ,acetabularia in #ahhi under the name ,a4 ,schencki2 this species has since been placed in ,d',archiac's genus ,acicularia#bif4 ,acicularia ,schencki#big bears a close resemblance as regards external form to ,acetabularia mediterranea4 ,in the latter species the walls of the terminal disc compartments are calcified1 and the cavity of each of the laterally fused members contains numerous free spores2 in ,acicularia1 the cavity of each disc-ray is occupied by a calcareous substance in the form of a spicule containing numerous cavities in each of which is a single sporangium4 ,a single spicule is seen in fig4 #cc1 ,h1 showing the spherical pockets in which the sporangia were originally situated4 ,this species1 ,acicularia ,schencki1 has been recorded from ,martinique1 ,guadeloupe1 ,brazil1 and a few other places4 ,the genus ,acicularia was founded by ,d',archiac for certain minute calcareous spicules found in the ,eocene sands 7,calcaire ,grossier7 of the ,paris basin4 ,d',archiac describes one species1 ,acicularia pavantina1 which he defines as follows3--8,polypier aciculaire1 largi1 et lgrement comprim sa partie suprieure1 qui est chancre au milieu4 ,surface couverte de petits pores simples1 nombreux1 disposs irrgulirement#bih40 ,the same species is figured also in ,michelin's ,iconographie ,zoophytologique1 and described as an organism of which the exact zoological position is uncertain#bii4 ,after these fossils had been placed in various divisions of the animal kingdom1 ,carpenter#cjj described several specimens as portions of foraminifera4 ,finally1 ,munier-,chalmas removed ,acicularia to the plant kingdom1 and 8with rare divination0 placed the genus among the ,acetabularieae4 ,the history of our knowledge of the true nature of ,acicularia is of unusual interest4 ,some of the specimens of this genus figured in ,carpenter's monograph have the form of imperfect long and narrow bodies tapering to a point at one end and broad at the other 7fig4 #cc1 ,f and ,g72 they are joined together laterally and pitted with numerous small cavities4 ,from the resemblance of such specimens to a fragment of the terminal fertile disc of the recent ,acetabularias1 ,munier-,chalmas referred the fossils to this type of algae4 ,in the living species which were then known the radiating chambers of the disc contained loose sporangia1 without any calcareous matrix filling the cavity of the chambers4 ,in the fossil ,acicularias1 on the other hand1 the manner of preservation of the pitted calcareous spicules pointed to the occurrence of sporangia embedded in cavities in a calcareous matrix4 ,subsequent to ,munier-,chalmas' somewhat daring conclusions as to the relation of ,acicularia to ,acetabularia1 ,solms-,laubach found that the species originally described by ,mbius as ,acetabularia ,schencki from ,guadeloupe presented exactly those characters in which the fossil specimens differ from ,acetabularia4 ,the genus ,acicularia formerly restricted to fossil species is now applied also to this single living species ,acicularia ,schencki4 ,the genus is thus defined by ,solms-,laubach3-- 8,discus fertilis terminalis e radiis inter se conjunctis formatus1 coronis et inferiore et superiore praeditis1 sporae massa mucosa calce incrustata coalitae1 pro radio spiculam solidam cuneatam formantes#cja40 ,as ,solms-,laubach points out in his recent monograph1 ,munier-,chalmas' conjecture1 8which had little to support it in the fossil material1 has been more recently proved true in the most brilliant fashion by the discovery of a living species of this genus40 #a4 ,acicularia ,andrussowi ,solms#cjb4 ,fig4 #cc1 ,c and ,d4 ,this species was first described by ,andrussow#cjc as ,acetabularia miocenica from the ,crimea4 ,it occurs in ,miocene rocks south of ,sevastopol1 and1 with ,ostrea and ,pecten1 forms masses of white limestone4 ,in each sporangial ray of the disc the cavity contains a calcareous spicula bearing spore cavities in four rows4 8,round each spore-cavity there is a circular zone which stands out1 when viewed in reflected light1 through its white colour against the central mass of the spicule1 though a sharp contour is not visible#cjd40 ,fig4 #cc1 ,c1 is taken from a somewhat diagrammatic sketch by ,andrussow2 it shows ten of the fertile rays of the disc4 ,the thick walls of the chambers are seen in the two lowest rays1 and in the next two rays the spore-cavities are represented4 ,a more accurate drawing1 from ,solms-,laubach's memoir1 is reproduced in fig4 #cc1 ,d4 ,the calcareous spicule with numerous spore-cavities shown in fig4 #cc1 ,h1 is from a fertile ray of the recent species ,acicularia ,schencki4 ,this corresponds to the spore-containing calcareous matrix in each ray of the disc of ,acicularia ,andrussowi ,solms4 ,the spicule copied in fig4 #cc1 ,f from one of ,carpenter's drawings#cje of an ,eocene specimen bears the closest resemblance to the recent spicule of fig4 #cc1 ,h1 and emphasizes the very close relationship between the fossil forms and the single rare tropical species4 #b4 ,acicularia miocenica ,reuss4 ,another ,tertiary species has been described under this name by ,reuss#cjf from the ,miocene of the ,vienna district1 from the ,leithakalk of ,moravia and elsewhere4 ,it agrees very closely with the recent species ,a4 ,schencki4 ,a section of one of the spicules of this species is shown in fig4 #cc1 ,e2 the dark patches represent the pockets in the calcareous spicule which were originally occupied by sporangia and spores4 ,cymopolia4 ,fig4 #cc1 ,a1 ,b1 ,m and ,n4 ,the genus ,cymopolia is at present represented by two species1 ,c4 barbata 7,l47 and ,c4 mexicana1 ,ag41 living in the ,gulf of ,mexico and off the ,canary ,islands4 ,cymopolia and ,acetabularia1 with several other calcareous algae1 are figured by ,ellis and other writers as members of the animal kingdom4 ,ellis speaks of the species of ,cymopolia which he figures as the ,rosary ,bead-,coralline of ,jamaica4 ,fig4 #cc1 ,m1 has been drawn from a figure published by ,ellis in his ,natural ,history of the ,corallines published in #ageecjg4 ,the thallus has the form of a repeatedly forked body1 of which the branches are divided into cylindrical joints thickly encrusted with carbonate of lime1 but constricted and uncalcified at the limits of each segment4 ,a tuft of hairs is given off from the terminal segment of each branch4 ,the axis of each branch of the thallus is occupied by a cylindrical and unseptate cell which gives off crowded whorls of lateral branches4 ,in the lower part of fig4 #cc1 ,m1 the calcareous investment has been removed1 and the branches are seen as fine hair-like appendages of the central cell4 ,the branches given off from the constricted portions of the axis are unbranched simple appendages1 but the others terminate in bladder-like swellings1 each of which bears an apical sporangium4 ,the sporangia are surrounded and enclosed by the swollen tips of four to six branches which spring from the summit of the sporangial branch4 ,fig4 #cc1 ,a1 represents part of a transverse section through the calcareous outer portion of a branch of ,cymopolia2 the darker portions or cavities in the calcareous matrix were originally occupied by the lateral branches and sporangia#cjh4 ,in ,fig4 #cc1 ,b1 the sporangial branch with the terminal sporangium and three of the investing branches are more clearly shown1 the surrounding calcareous investment and the thallus having been removed by the action of an acid4 ,in a transverse section of a branch from which the organic matter had been removed1 and only the calcareous matrix left1 one would see a central circular cavity surrounded by a thick calcareous wall perforated by radially disposed canals and containing globular cavities2 the canals and cavities being occupied in the living plant by branches and sporangia respectively4 ,the two circular cavities shown in the figure mark the position of the sporangia which are borne on branches with somewhat swollen tips4 ,from the summit the left-hand sporangial branch shown in fig4 #cc1 ,a1 three of the secondary branches are represented by channels in the calcareous matrix2 the two black dots on the face of the sporangiophore being the scars of the remaining two secondary branches4 ,by the lateral contact of the swollen ends of the ultimate branches enclosing the sporangia the whole surface of the thallus1 when examined with a lens1 presents a pitted appearance4 ,each pit or circular depression 7fig4 #cc1 ,n7 marks the position of the swollen tip of a branch4 ,this form of thallus represents a type which is met with in several members of the ,dasycladaceae4 ,it would carry us beyond the limits of a short account to describe additional recent genera which throw light on the numerous fossil species4 ,for further information as to the recent members of the family1 the student should refer to ,murray's ,seaweeds#cji1 and for a more detailed memoir on the group to ,wille's recent contribution to the ,pflanzenfamilien#caj of ,engler and ,prantl4 ,among the various special contributions to our knowledge of the ,dasycladaceae1 those by ,munier-,chalmas#caa1 ,cramer#cab1 ,solms-,laubach#cac1 and ,church#cad1 may be mentioned4 ,sidenote3 ,,palaeozoic ,,siphoneae4 ,the publication of a short preliminary note by ,prof4 ,munier-,chalmas in the ,comptes ,rendus for #ahgg was the means of calling attention to the exceptional importance of the calcareous ,siphoneae as algae possessing an interesting past history1 of which satisfactory records had been preserved in rocks of various ages4 ,decaisne had pointed out in #ahdb that certain marine organisms previously regarded as animals should be transferred to the plant kingdom4 ,such seaweeds as ,halimeda1 ,udotea1 ,penicillus and others were thus assigned to their correct position4 ,many fossil algae belonging to this group continued to be dealt with as ,foraminifera until ,munier-,chalmas demonstrated their true affinities4 ,in ,gmbel's monograph on the so-called ,nullipores found in limestone rocks1 published in #ahgacae1 several examples of siphoneous algae are included among the fossil ,protozoa4 ,in recent years there have been several additions to an already long list of fossil ,siphoneae4 ,in addition to the numerous and well-preserved specimens1 representing a large number of generic and specific forms1 which have been collected from the ,eocene of the ,paris basin1 there is plenty of evidence of the abundance of the members of the ,dasycladaceae in the ,triassic seas4 ,in the ,triassic limestones of the ,tyrol1 as well as in other regions1 the calcareous bodies of siphoneous algae have played no inconsiderable part as agents of rock-building#caf4 ,genera have been recorded from ,silurian and other ,palaeozoic horizons1 and there is no doubt that the ,verticillate ,siphoneae of to-day are the remnants of an extremely ancient family1 which in former periods was represented by a much more widely distributed and more varied assemblage of species4 ,there is probably no more promising field of work in the domain of fossil algae than the further investigation of the numerous forms included in ,munier-,chalmas' class of ,siphoneae ,verticillatae4 ,a brief description of a few genera from different geological horizons must suffice to draw attention to the character of the data for a phylogenetic history of this group4 ,the fossil examples of the genus ,cymopolia 7,polytrypa7 were originally described by ,defrance#cag in the ,dictionnaire des ,sciences ,naturelles as small polyps under the generic name ,polytrypa4 ,in the ,eocene sands of the ,paris basin there have been found numerous specimens of short1 calcareous tubes which ,munier-,chalmas has shewn are no doubt the isolated segments of an alga practically identical with the recent ,cymopolia4 ,a section#cah through one of the fossil segments presents precisely the same features as those which are represented in fig4 #cc1 ,a4 ,the habit of the ,eocene alga and its minute structure were apparently almost identical with those of the recent species1 ,cymopolia barbata4 ,the two drawings of ,cymopolia reproduced in fig4 #cc1 ,a and ,b1 have been copied from ,munier-,chalmas' note in the ,comptes ,rendus#cai2 the corresponding figures given by this author of the ,eocene species 7,cymopolia elongata ,deb47 are practically identical with figs4 ,a and ,b1 and show no points of real difference4 ,the segments of the thallus of the fossil species1 as figured by ,defrance#cbj1 appear to be rather longer than those of the recent species4 ,the calcareous investment of the axial cell of the thallus was traversed by regular verticils of branches or #8leaves'2 the central branch of each whorl terminates in an oval sporangial cavity1 exactly as in fig4 #cc1 ,a and ,b2 and from the top of this branch there is given off a ring of slender prolongations which terminate on the surface of the calcareous tube as regularly disposed depressions1 which were no doubt originally occupied by their swollen distal ends as in the recent species4 ,vermiporella4 ,this generic name was proposed by ,stolley for certain branched and curved tubes found in ,silurian boulders from the ,north ,german drift#cba4 ,the tubes have a diameter of #e-a mm41 and are perforated by radial canals which probably mark the position of verticils of branches given off at right angles to the central axis4 ,the surface of the tubes is divided into regular hexagonal areas4 ,the resemblance of these ,silurian fossils to ,diplopora and other genera favours their inclusion in the ,verticillate ,siphoneae4 ,sycidium4 ,fig4 #cb1 ,b4 ,the fossils included in this genus were first described by ,sandberger from the middle ,devonian rocks of the ,eifel1 and referred by him to the animal kingdom4 ,more recently ,deecke has suggested the removal of the genus to the calcareous ,siphoneae1 and such a view appears perfectly reasonable1 although without more data it is not possible to speak with absolute certainty4 ,sycidium melo4 7,sandb47 ,fig4 #cb1 ,b4 ,the specimen represented in fig4 #cb1 ,b 7i71 7ii71 drawn from ,deecke's figures#cbb1 has the form of a small oval calcareous body1 #a mm4 in transverse diameter and #a-ac mm4 in longitudinal diameter4 ,it is pointed at one end and flattened at the other4 ,at the flatter end there is a circular depression1 continued into a funnel-shaped cavity1 and on the walls of this cavity there are #ah-bj radially disposed ribs1 which extend over the surface of the whole body4 ,a series of transverse ribs intersects the vertical ribs at right angles4 ,the calcareous wall is perforated by numerous whorls of circular pores1 and the internal cavity is a simple undivided space4 ,each of these oval bodies 7fig4 #cc1 ,b7 is probably the segment of a thallus1 and the perforations in the wall may have been originally occupied by lateral prolongations from the unseptate axial cell of the thallus4 ,sycidium bears a fairly close resemblance to the ,tertiary ,ovulites4 ,diplopora4 ,fig4 #ce1 ,a and ,b4 ,this genus of algae is characteristic of ,triassic rocks1 and is especially abundant in ,muschelkalk and ,lower ,keuper limestones of the ,alps1 ,silesia1 and elsewhere4 ,the thallus1 or rather the calcareous portion of the thallus1 has the form of a thick-walled tube1 with a diameter of about #d mm41 and occasionally reaching a length of #ej mm4 ,at one end the tube has a rounded and closed termination1 and the wall is pierced throughout its whole length by regular whorls of fine canals4 ,diplopora agrees with ,cymopolia in its main features4 ,illustration3 ,,fig4 #ce4 ,a1 ,b1 ,diplopora4 #b4 ,c1 ,d1 ,gyroporella 7after ,benecke4 #d74 ,e1 ,calcareous segments of ,penicillus1 from a specimen in the ,british ,museum4 #e4 ,f1 a single segment of ,ovulites margaritula ,lam4 #d4 ,g1 ,confervites chantransioides ,born4 7after ,bornemann4 #aej74 ,fig4 #ce1 ,a1 affords a diagrammatic view of a ,diplopora tube1 and shews the arrangement of the numerous whorls of canals4 ,in fig4 #ce1 ,b1 a piece of limestone is represented containing several ,diploporas cut across transversely and more or less obliquely4 ,in an obliquely transverse section of a tube perforated by horizontal canals the cavities of the canals necessarily appear as holes or discontinuous canals in the substance of the calcareous wall4 ,the manner of occurrence of the specimens points to the abundance of this genus in the ,triassic seas1 and suggests that the calcareous tubes of ,diplopora may have been important factors in the building up of limestone sediments#cbc4 ,in many instances no doubt the carbonate of lime of the thallus has been dissolved and recrystallised1 and the original form completely obliterated4 ,as in the rocks built up largely of calcareous ,florideae 7p4 #ahe7 which have lost their structure1 it is a legitimate inference that some of the limestone rocks which shew no trace of organic structure may have been in part derived from the calcareous incrustation of various algal genera4 ,gyroporella4 ,fig4 #ce1 ,c and ,d4 ,in this genus from the ,alpine ,trias the structure of the calcareous tube is very similar to that in ,diplopora1 but in ,gyroporella the canals form less distinct whorls and are closed externally by a small plate1 as seen in figs4 #ce1 ,c and ,d4 ,as ,solms-,laubach has pointed out1 the branch-systems of ,diplopora1 ,gyroporella and other older genera are much simpler than in the ,tertiary genera ,dactylopora and others#cbd4 ,a species of ,gyroporella1 ,g4 bellerophontis1 has recently been described by ,rothpletz#cbe from ,permian rocks in the ,southern ,tyrol4 ,the thallus is tubular in form and has a diameter of #e-a mm4 ,dactylopora4 ,the genus ,dactylopora was founded by ,lamarck#cbf on some fossil specimens from the ,calcaire ,grossier and included among the ,zoophytes4 ,d',orbigny afterwards included it among the ,foraminifera1 and the structure of the calcareous body has been described by ,carpenter#cbg and other writers on the ,foraminifera4 ,in a specimen of ,dactylopora cylindracea ,lam4 from the ,paris basin1 for which ,i am indebted to ,munier-,chalmas1 the tubular thallus measures #d mm4 in diameter2 at the complete end it is closed and bluntly rounded4 ,the wall of the tube is perforated by numerous canals1 and contains oval cavities which were no doubt originally occupied by sporangia4 ,the shape of the specimens is similar to that of ,diplopora1 but the canals and cavities present a characteristic and more complex appearance1 when seen in a transverse section of the wall1 than in the older genus ,diplopora4 ,gmbel has given a detailed account of this ,tertiary genus in his memoir on ,die sogenannten ,nulliporen#cbh2 he distinguishes between ,dactyloporella and ,gyroporella by the existence of cavities in the calcareous wall of the tube in the former genus1 and by their absence in the latter4 ,the oval cavities in a ,dactyloporella were originally occupied by sporangia2 in ,diplopora and ,gyroporella the sporangia were probably borne externally and on an uncalcified portion of the thallus4 ,in addition to the few examples of fossil species described above there are numerous others of considerable interest1 which illustrate the great wealth of form among the ,tertiary and other representatives of the ,verticillate ,siphoneae4 ,reference has already been made to ,vermiporella as an example of a ,silurian genus4 ,other genera have been described by ,stolley from ,silurian boulders in the ,north-,german drift under the names ,palaeoporella1 ,dasyporella and ,rhabdoporella#cbi2 the latter genus is compared with the ,triassic ,diplopora1 and the two preceding with the recent ,bornetella4 ,schlter has transferred a supposed ,devonian ,foraminiferal genus1 ,coelotrochium#ccj1 to the list of ,palaeozoic ,siphoneae4 ,munier-,chalmas regards some of the fossils described by ,saporta under the name of ,goniolina#cca1 and classed among the inflorescences of pro-angiospermous plants1 as examples of ,jurassic ,siphoneae4 ,the shape and surface-features of some of the examples of ,goniolina suggest a comparison with ,echinoid spines1 but the resemblance which many of the forms in the ,sorbonne collection present to large calcareous ,siphoneae is still more striking4 ,a comparison of ,saporta's fig4 #e1 ,pl4 xxxiii4 and fig4 #d1 ,pl4 xxxii4 in volume iv4 of the ,flore ,jurassique1 with the figures given by ,solms-,laubach#ccb and ,cramer#ccc of species of ,bornetella brings out a close similarity between ,goniolina and recent algae2 the chief difference being the greater size of the fossil forms4 ,the possibility of confounding ,echinoid spines with calcareous ,siphoneae is illustrated by ,rothpletz#ccd1 who has expressed the opinion that ,gmbel's ,haploporella fasciculata is not an alga but the spine of a sea-urchin4 ,among ,cretaceous forms1 in addition to ,goniolina1 which passes upwards from ,jurassic rocks1 ,triploporella#cce and other genera have been recorded4 ,uteria#ccf is an interesting type of ,tertiary genera2 it occurs in the form of barrel-shaped rings1 which are probably the detached segments of a form in which the central axial cell was encrusted with carbonate of lime1 but the sporangia and the whorls of branches differed from those of ,cymopolia in being without a calcareous investment4 b4 ,,confervoideae4 ,without attempting to describe at length the fossil forms referred to this division of the ,chlorophyceae1 there is one fossil which deserves a passing notice4 ,brongniart in #ahbhccg instituted the generic term ,confervites for filamentous fossils resembling recent species of confervoid algae4 ,numerous fossils have been referred to this genus by different authors1 but they are for the most part valueless and need not be further considered4 ,in #ahhg ,bornemann described some new forms which he referred to this genus from the ,cambrian rocks of ,sardinia4 ,he describes the red marble of ,san ,pietra1 near ,masne1 as being in places full of the delicate remains of algae having the form of branched filaments1 and appearing in sections of the rock as white lines on a dark crystalline matrix4 ,in fig4 #ce1 ,g1 one of these ,sardinian specimens is represented4 ,this form is named ,confervites ,chantransioides#cch2 the thallus consists of branched cell-filaments1 having a breadth of #f-g1 and composed of ovate cells4 ,it is possible that this is a fragment of a ,cambrian alga1 but the figures and descriptions do not afford by any means convincing evidence4 ,from post-,tertiary beds various genera1 such as ,vaucheria and others1 have been recorded1 but they possess but little botanical value4 ,c4 ,,incertae ,,sedis4 ,fossils in ,boghead #8,coal' referred by some authors to the ,chlorophyceae4 ,during the last few years much has been written by two ,french authors1 ,dr ,renault and ,prof4 ,bertrand1 on the subject of the so-called ,boghead of ,france1 ,scotland1 and other countries4 ,they hold the view that the formation of the extensive beds of this carbonaceous material was due to the accumulation and preservation of enormous numbers of minute algae which lived in ,permo-,carboniferous lakes4 ,in an article contributed to ,science-,progress in #ahie ,i ventured to express doubts as to the correctness of the conclusions of ,,mm4 ,renault and ,bertrand#cci4 ,since then ,prof4 ,bertrand has very kindly demonstrated to me many of his microscopic preparations of various ,bogheads1 and ,i am indebted to ,prof4 ,bayley ,balfour of ,edinburgh for an opportunity of examining a series of sections of the ,scotch ,boghead4 ,the examination of these specimens has convinced me of the difficulties of the problems which many investigators have tried to solve1 but it has by no means led me to entirely adopt the views expressed by ,,mm4 ,bertrand and ,renault4 ,sidenote3 ,,boghead4 ,the ,boghead or ,torbanite of ,scotland was rendered famous by a protracted lawsuit tried in ,edinburgh from ,july #bith to ,august #dth1 #ahec4 ,a lease had been granted by ,mr and ,mrs ,gillespie1 of ,torbanehill1 in ,fifeshire1 to ,messrs ,james ,russell and ,son1 coal-masters of ,falkirk1 of 8the whole coal1 ironstone1 iron-ore1 limestone1 and fire-clay 7but not to comprehend copper1 or any other minerals whatsoever1 except those specified7 with lands of ,torbanehill#cdj40 ,after the ,boghead had been worked for two years the ,gillespies challenged the right of ,messrs ,russell1 and argued that the valuable mineral ,torbanite was not included among the substances named in the agreement4 ,the defendants maintained that it was a coal1 known as gas-1 cannel- or parrot-coal4 ,a verdict was given for the defendants4 ,some of the scientific experts who gave evidence at the trial considered that the ,boghead afforded indications of organic structure1 while others regarded it as essentially mineral in origin4 ,the ,torbanite or ,boghead is a close-grained brown rock1 of peculiar toughness and having a subconchoidal fracture4 ,it contains about #fe carbon1 with some hydrogen1 oxygen1 sulphur1 and mineral substances4 ,a thin section examined under the microscope presents the appearance of a dark and amorphous matrix1 containing numerous oval1 spherical and irregularly shaped bright orange-yellow patches4 ,fig4 #cf1 #a shows the manner of occurrence of the yellow bodies in a piece of ,scotch ,boghead1 as seen in a slightly magnified horizontal section4 ,under a higher power the light patches in the figure reveal traces of a faint radial striation1 which in some cases suggests the occurrence of a number of oval or polygonal cells4 ,the ,autun ,boghead possesses practically the same structure4 ,the yellow bodies are often sufficiently abundant to impart a bright yellow colour to a thin section4 ,if the section is vertical the coloured bodies are seen to be arranged in more or less regular layers parallel to the plane of bedding4 ,the ,kerosene shale of ,new ,south ,wales agrees closely with the ,scotch and ,french ,boghead2 it is approximately of the same geological age1 and is largely made up of orange or yellow bodies similar to those of the ,european ,boghead1 but much more clearly preserved4 ,the nature and manner of formation of the various forms of coal should be dealt with in a later chapter devoted to the subject of plants as rock-builders1 but in view of the recent statements as to the algal nature of these bituminous deposits it may not be out of place to state briefly the main conclusions of the ,french authors4 ,,mm4 ,renault and ,bertrand regard each of the yellow bodies in the ,european and ,australian ,boghead as the thallus of an alga4 ,to the form which is most abundant in the ,kerosene shale they have given the generic name of ,reinschia1 while that in the ,scotch and ,french ,boghead is named ,pila4 ,reinschia4 ,fig4 #cf1 #c4 ,a section of a piece of ,kerosene shale at right angles to the bedding appears to be made up of fairly regular layers of flattened elliptical sacs of an orange or yellow colour4 ,each sac or thallus is about #cjj in length and #aej broad 7fig4 #cf1 #c74 ,a single row of cells constitutes the wall surrounding the central globular cavity4 ,the cells are more or less pyriform in shape1 and the cell-cavities are filled with a dark substance1 described by ,renault and ,bertrand as protoplasm1 and the cell-walls are fairly thick4 ,in some of the larger specimens there are often found a few smaller sacs enclosed in the cavity of the partially disorganised mother-thallus4 ,in the larger specimens the wall is usually invaginated in several places1 giving the whole thallus a lobed or brain-like appearance4 ,the supposed alga1 which makes up ths of the contents of a block of ,kerosene shale1 is named ,reinschia ,australis2 it is regarded by the authors of the species as nearly related to the ,hydrodictyaceae or ,volvocineae4 ,illustration3 ,,fig4 #cf1 #a4 ,section of a piece of ,scotch ,torbanite4 ,slightly enlarged4 #b4 ,pila bibractensis from the ,autun ,boghead1 #bhb 7after ,bertrand74 #c4 ,reinschia ,australis1 from the ,kerosene shale of ,new ,south ,wales1 #eib 7after ,bertrand74 ,in the ,kerosene shale from certain localities in ,new ,south ,wales ,bertrand recognises a second form of thallus1 which he refers to the genus ,pila1 characteristic of the ,european ,bogheads4 ,pila4 ,fig4 #cf1 #b4 ,the 8thallus0 characteristic of the ,scotch ,boghead has been named ,pila scotica1 and that of the ,autun ,boghead1 ,pila bibractensis4 ,in the latter form1 which has been studied in more detail by ,,mm4 ,renault and ,bertrand1 the thallus consists of about #f-gjj cells1 and is irregularly ellipsoidal in form1 from #ahi-bbemm4 in length1 and #acf-afjmm4 broad4 ,the surface-cells are radially disposed and pyramidal in shape1 the internal cells are polygonal in outline and less regularly arranged 7fig4 #cf1 #b74 ,the ,pila thalli make up ths of the mass in an average sample of the ,autun ,boghead4 ,the ,autun ,boghead often contains siliceous nodules1 and sections of these occasionally include cells of a ,pila in which the protoplasmic contents and nuclei have been described by the ,french authors4 ,the evidence for the existence of these supposed nuclei is1 however1 not entirely satisfactory2 sections of silicified thalli which were shown to me by ,prof4 ,bertrand did not satisfy me as to the minute histological details recognised by ,bertrand and ,renault4 ,the species of ,pila are compared with the recent genus ,celastrum1 and regarded as most nearly allied to the ,chroococcaceae or ,pleurococcaceae among recent algae4 ,prof4 ,bornet#cda has suggested ,gomphosphaeria as a genus which presents a resemblance to the ,autun ,pila4 ,in addition to the ,bogheads of ,autun1 ,torbanehill1 and ,new ,south ,wales1 there are similar ,palaeozoic deposits in ,russia1 ,america1 and various other parts of the world4 ,full details of the structure of ,boghead and the supposed algae referred to ,reinschia1 ,pila1 and other genera will be found in the writings of ,bertrand and ,renault#cdb4 ,the ,kerosene shale of ,new ,south ,wales affords the most striking and well-preserved examples of the cellular orange and yellow bodies referred to as the globular thalli of algae4 ,it is almost impossible to conceive a purely inorganic material assuming such forms as those which occur in the ,australian ,boghead4 ,on the other hand1 it is hardly less easy to understand the possibility of such explanations as have been suggested of the organic origin of these characteristic bodies4 ,the ground-mass or matrix of the ,boghead is referred to a brown ulmic precipitate thrown down on the floor of a ,permian or ,carboniferous lake1 probably under the action of calcareous water4 ,in this material there accumulated countless thalli of minute gelatinous algae1 which probably at certain seasons completely covered the surface of the waters1 as the fleurs d'eau in many of our fresh-water lakes4 ,in addition to the thalli of ,reinschia and ,pila the ,bogheads contain a few remains of various plant fragments1 pollen-grains1 and pieces of wood4 ,fish-scales and the coprolites of reptiles and fishes occur in some of the beds4 ,on a piece of ,kerosene shale in the ,woodwardian ,museum1 ,cambridge1 there are two well-preserved graphitic impressions of the tongue-shaped fronds of ,glossopteris ,browniana1 ,brongn4 ,there can be little doubt that the beds of ,boghead were deposited under water as members of a regular sequence of sedimentary strata4 ,the yellow bodies which form so great a part of the beds are practically all of the same type4 ,reinschia and ,pila cannot always be distinguished1 and it would seem that there are no adequate grounds for instituting two distinct genera and referring them to different families of recent algae4 ,stated briefly1 my conclusion is that the algae of the ,french authors may be definite organic bodies1 but it is unwise to attempt to determine their affinities within such narrow limits as have been referred to in the above rsum4 ,the structure of the bituminous deposits is worthy of careful study1 and it is by no means impossible that further research might lead us to accept the view of the earlier investigators1 that the brightly coloured organic-like bodies may be inorganic in origin4 ,d4 ,,rhodophyceae4 7,,florideae4 ,,red ,,algae47 ,the thallus of the members of this group assumes various forms1 and consists of branched cell-filaments of a more or less complex structure4 ,cells of the thallus contain a red colouring matter in addition to the green chlorophyll4 ,the reproduction is asexual and sexual2 the formation of asexual reproductive cells 7tetraspores7 in groups of four in sporangia is a characteristic method of reproduction4 ,sexual reproduction is effected by means of distinct male and female cells4 ,with the exception of a few fresh-water genera all the red algae are marine4 ,the ,rhodophyceae1 like the ,cyanophyceae and ,chlorophyceae1 include a shell-boring form which has been found in the common razor-shell#cdc4 ,several genera live as endophytes in the tissues of other algae4 ,the recent species of this section of algae are characteristic of temperate and tropical seas4 ,one subdivision of the red algae1 the ,corallinaceae1 is extremely important from a geological point of view and must be dealt with in some detail4 ,,corallinaceae4 ,the thallus is usually encrusted with carbonate of lime2 it is of a branched cylindrical form in the well-known ,corallina officinalis1 ,linn4 of the ,british coasts1 of an encrusting and foliaceous type1 in the genus ,lithophyllum1 and of a more coral-like form in the genus ,lithothamnion4 ,the reproductive organs occur in conceptacles1 having the form of small depressed cavities in the thallus1 or projecting as warty swellings above the surface of the plant4 ,asexual reproduction is by means of tetraspores formed in conceptacles resembling those containing the sexual cells4 ,the ,corallinaceae may be subdivided into the two families ,melobesieae and ,corallineae#cdd4 ,melobesieae4 ,thallus encrusting1 leaf- or coral-like2 unsegmented4 7,melobesia1 ,lithophyllum1 ,lithothamnion47 ,corallineae4 ,cylindrical filamentous and segmented thallus4 7,amphiroa and ,corallina47 ,the genus ,corallina is the best known ,british representative of the ,corallinaceae4 ,with other members of the group it was long regarded as a coralline animal1 and it is only comparatively recently that the plant-nature of these forms has been generally admitted4 ,lithophyllum1 ,lithothamnion1 ,melobesia1 and other genera of the ,corallinaceae and some of the ,siphoneae play a very important part in the building and cementing of coral-reefs4 ,the pink or rose-coloured calcareous thallus of some of these calcareous algae or ,nullipores imparts to coral-reefs a characteristic appearance4 ,in some cases1 indeed1 the coral-reefs are very largely composed of algae4 ,saville ,kent#cde describes the ,corallines or ,nullipores of the ,australian ,barrier-reef as furnishing a considerable quota towards the composition of the coral rock4 ,mr ,stanley ,gardiner1 who accompanied the coral-boring expedition to the island of ,funafuti1 has kindly allowed me to quote the following extract from his notes1 which affords an interesting example of the importance of calcareous algae as reef-building organisms4 8,it is quite a misnomer to speak of the outer edge of a reef like this 7,rotuma ,island7 as being formed of coral4 ,it would be far better to call it a ,nullipore reef1 as it is completely encrusted by these algae1 while outside in the perfectly clear water1 #aj to #ae fathoms in depth1 the bottom has a most brilliant appearance from masses of red1 white and pink ,nullipores1 with only a stray coral here and there40 ,agassiz#cdf has given an account of the occurrence of immense masses of ,nullipores 7,udotea1 ,halimeda etc47 in the ,florida reefs2 his description is illustrated by good figures of these algae4 ,in the ,mediterranean there are true ,nullipore reefs1 which are interesting geologically as well as botanically4 ,walther#cdg has described one of these limestone-banks in the ,gulf of ,naples which occurs about #a kilometre from the coast and #cj metres below the surface of the water4 ,every dredging1 he says1 brings up numberless masses of ,lithothamnion fasciculatum 7,lamarck71 and ,l4 crassum 7,phil474 ,between the branches of the algae1 gasteropods and other animals become completely enclosed by the growing plants1 while diatoms1 foraminifera1 and other forms of life are abundant4 ,water percolating through the mass gradually destroys the structure of the algal thalli1 and in places reduces the whole bank to a compact structureless limestone4 ,the same author#cdh has also called attention to the importance of ,lithophyllum as a constructive element in the coral-reefs off the ,sinai peninsula4 ,lithothamnion a typical genus of the ,corallinaceae may be briefly described4 ,lithothamnion4 ,fig4 #cg4 ,philippi#cdi was the first writer to describe this and other genera as plants4 ,he gave the following definition of ,lithothamnion3 8,stirps calcarea rigida1 e ramis cylindricis vel compressiusculis dichotoma ramosis constans40 ,the thallus of ,lithothamnion grows attached to the face of a rock or other foundation1 and forms a hard1 stony mass1 assuming various coralline shapes4 ,the exposed face may have the form of numerous short branches or of an irregular warty surface4 ,in section 7fig4 #cg1 ,a47 the lower part of the thallus is seen to be made up of rows of cells radiating out from a central point1 and the upper portion consists of vertical and horizontal rows of cells4 ,the whole body is divided up into a large number of small cells by anticlinal and periclinal walls1 and possesses an evident cellular as distinct from a tubular structure4 ,conceptacles containing reproductive organs are either sunk in the thallus or project above the surface4 ,the two types of structure in a single thallus are shown in fig4 #cg1 ,a1 also a conceptacle containing tetraspores4 ,illustration3 ,,fig4 #cg1 ,a4 ,section of a recent ,lithothamnion 7after ,rosanoff#cej1 #bjj74 ,b4 ,section of ,lithothamnion suganum1 ,roth 7after ,rothpletz#cea1 #ajj74 ,c4 ,a conceptacle with tetraspores from a ,tertiary ,lithothamnion 7after ,frh#ceb1 #cjj74 ,d4 ,sphaerocodium ,bornemanni ,roth1 7after ,rothpletz1 #aej74 ,in the closely allied ,lithophyllum the thallus is encrusting1 and in section it presents the same appearance as the lower part of a ,lithothamnion thallus4 ,species of ,lithothamnion occur in the ,mediterranean ,sea1 and are abundant in the arctic regions#cec1 while on the ,british coasts the genus is represented by four species#ced4 ,some large specimens of ,lithothamnion and ,lithophyllum are exhibited in one of the show-cases in the botanical department of the ,british ,museum4 ,for the best figures and descriptions of recent species reference should be made to the works of ,hauck1 ,rosanoff1 ,rosenvinge1 ,kjellman and ,solms-,laubach#cee4 ,it is to be expected that such calcareous algae as ,lithothamnion should be widely represented by fossil forms4 ,in addition to the botanical importance of the data furnished by the fossil species as to the past history of the ,corallinaceae1 there is much of geological interest to be learnt from a study of the manner of occurrence of both the fossil and recent representatives4 ,as agents of rock-building the coralline algae are especially important4 ,the late ,prof4 ,unger#cef in #aheh gave an account of the so-called ,leithakalk of the ,tertiary ,vienna basin1 and recognised the importance of fossil algae as rock-forming organisms4 ,the ,miocene ,leithakalk1 which is widely used in ,vienna as a building stone#ceg1 consists in part of limestone rocks consisting to a large extent of ,lithothamnion4 ,since the publication of ,unger's work several writers have described numerous fossil species of ,lithothamnion from various geological horizons4 ,a few examples will suffice to illustrate the range and structure of this and other genera of the ,corallinaceae4 ,in dealing with the fossil species it is often impossible to make use of those characters which are of primary importance in the recognition of recent species4 ,the fossil thallus is usually too intimately associated with the surrounding rock to admit of any use being made of external form as a diagnostic feature4 ,the size and form of the cells must be taken as the chief basis on which to determine specific differences4 ,in the absence of conceptacles or reproductive organs it is not always easy to distinguish calcareous algae from fossil ,hydrozoa or ,bryozoa4 ,in many instances1 however1 apart from the nature and size of the elements composing the thallus1 the conceptacles afford a valuable aid to identification4 ,an example of a fossil conceptacle containing tetraspores is shown in fig4 #cg1 ,c2 it is from a ,tertiary species of ,lithothamnion1 described by ,frh from ,montvraz in ,switzerland4 #a4 ,lithothamnion mamillosum ,gmb4 ,fig4 #cb1 ,a 7i7 and 7ii74 7p4 #aee47 ,this species was first recorded by ,gmbel#ceh from the ,upper ,cretaceous 7,danian7 rocks of ,petersbergs1 near ,mastricht1 on the ,belgian frontier4 ,it was originally described as a ,bryozoan4 ,the thallus has the form of an encrusting calcareous structure bearing on its upper surface thick nodular branches1 as shown in fig4 #cb1 ,a 7ii72 in section1 ,a 7i71 the thallus consists of a regular series of rectangular cells4 ,the specific name mamillosum has also been given to a recent species by ,hauck#cei1 but probably in ignorance of the existence of ,gmbel's ,cretaceous species4 #b4 ,lithothamnion suganum ,roth4 ,fig4 #cg1 ,b4 ,the section of this form given in fig4 #cg1 ,b shows three oval conceptacles filled with crystalline material4 ,the two lower conceptacles originally communicated with the surface of the thallus1 but as in recent species the deeper portions of the algal body became covered over by additions to the surface1 forming merely dead foundations for new and overlying living tissues4 ,the cells of the thallus have a breadth of #g-i1 and a length of #i-ab4 ,the specimen was obtained from a ,lithothamnion bank1 probably of ,upper ,oligocene age1 in ,val ,sugana#cfj1 in the ,austrian ,tyrol4 ,numerous other species of ,jurassic1 ,cretaceous and ,tertiary age might be quoted1 but the above may suffice to illustrate the general characters and mode of occurrence of the genus4 ,it is important that the student should become familiar with the ,lithothamnion and ,lithophyllum types of thallus1 in view of their frequent occurrence in crystalline limestone rocks and in such comparatively recent deposits as those of upraised coral-reefs4 ,the coral-rock of ,barbados and other ,west-,indian islands affords a good illustration of the manner of occurrence of fossil coralline algae in association with corals and other organisms#cfa4 ,in the fossil species of ,lithothamnion hitherto recorded there do not appear to be any important features in which they differ from recent forms2 the geological history of the genus so far as it is known1 favours the view that the generic characters are of considerable antiquity4 ,solenopora4 ,fig4 #ch4 ,mr ,a4 ,brown#cfb1 of ,aberdeen1 has recently brought forward good evidence for including various calcareous fossils1 described by several authors under different names and referred to various genera of fossil animals1 in the genus ,solenopora1 which he places among the coralline algae4 ,species of this genus have been described from ,england1 ,scotland1 ,esthonia1 ,russia1 and other countries4 ,the geological range of ,solenopora appears to be from ,ordovician to ,jurassic rocks2 in some cases it is an important constituent of beds of limestone4 ,solenopora compacta 7,billings74 ,fig4 #ch4 ,this species was originally described by ,billings as ,stromatopora compacta1 and afterwards defined by ,nicholson and ,etheridge4 ,the thallus forms sub-spheroidal masses1 from the size of a hemp-seed to that of an orange4 ,the external surface is lobulate2 the fractured surface has a porcellaneous and sometimes a fibrous appearance1 and is usually white or light brown in colour4 ,in vertical section 7fig4 #ch1 ,b7 the cells are elongated and arranged in a radiating and parallel fashion2 they often occur in concentric layers4 ,the cells have a diameter of about mm4 and possess distinctly undulating walls1 as seen in a tangential section 7fig4 #ch1 ,a74 ,brown describes certain larger cells in the thallus 7fig4 #ch1 ,a7 as sporangia#cfc1 but it is difficult to recognise any distinct sporangial cavities in the drawing4 ,the example figured is from the ,trenton limestone of ,canada2 a variety of the same species has been recorded from the ,ordovician rocks of ,girvan in ,ayrshire4 ,there appear to be good reasons for accepting ,brown's conclusion that ,solenopora belongs to the ,corallinaceae rather than to the ,hydrozoa1 among which it was originally included4 ,after comparing ,solenopora with recent genera of ,florideae1 ,brown concludes that 8the forms of the cells and cell-walls1 the method of increase1 and the arrangement of the tissue cells in the various species of ,solenopora bear strong evidence of relationship between that genus and the calcareous algae#cfd40 ,illustration3 ,,fig4 #ch4 ,solenopora compacta 7,billings74 ,a4 ,tangential section4 #ajj4 ,b4 ,vertical section4 #ej4 7,after ,brown47 ,the importance of the calcareous ,rhodophyceae has been frequently emphasised by recent researches1 and our knowledge of the rock-building forms is already fairly extensive4 ,we possess evidence of the existence of species of different genera in ,ordovician seas1 as well as in those of the ,silurian1 ,triassic1 ,jurassic1 and more recent periods4 ,it is reasonable to prophesy that further researches into the structure of ancient limestones will considerably extend our knowledge of the geological and botanical history of the ,corallinaceae4 ,numerous fossils have been described as examples of other genera#cfe of ,rhodophyceae than those included in the ,corallinaceae1 but these possess little or no scientific value and need not be considered4 ,e4 ,,phaeophyceae 7,,brown ,,algae74 ,olive-brown algae1 thallus often leathery in texture1 composed of cell-filaments or parenchymatous tissue1 in some cases exhibiting a considerable degree of internal differentiation4 ,the sexual reproductive organs may be either in the form of passive egg-cells and motile antherozoids or of motile cells showing no external sexual difference4 ,with one or two exceptions all the genera are marine4 ,they have a wide distribution at the present day1 and are especially characteristic of far northern and extreme southern latitudes4 ,the gigantic forms ,lessonia1 ,macrocystis and others already alluded to1 belong to this group2 also the genus ,sargassum1 of which the numberless floating plants constitute the characteristic vegetation of the ,sargasso ,sea4 ,palaeobotanical literature is full of descriptions of supposed fossil representatives of the brown algae1 but only a few of the recorded species possess more than a very doubtful value2 most of them are worthless as trustworthy botanical records4 ,many of the numerous impressions referred to as species of ,fucoides and other genera present a superficial resemblance to the thallus of the common ,bladder-wrack and other brown seaweeds4 ,such similarity of form1 however1 in the case of flat and branched algal-like fossils is of no scientific value4 ,in many instances the impressions are probably those of an alga1 but they are of no botanical interest4 ,the flat and forked type of thallus of ,fucus1 ,chondrus crispus 7,l47 and other members of the ,phaeophyceae is met with also among the red and green algae1 to say nothing of its occurrence in the group of thalloid ,liverworts1 or of the almost identical form of various members of the animal kingdom4 ,the variety of form of the thallus in one species is well illustrated by the common ,chondrus crispus 7,l474 ,this alga was described by ,turner#cff in his classic work on the ,fuci under the name of ,fucus crispus as 8a marine ,proteus40 ,it affords an interesting example of the different appearance presented by the same species under different conditions1 and at the same time it furnishes another proof of the futility of relying on imperfectly preserved external features as taxonomic characters of primary importance4 ,an example of a supposed ,jurassic ,fucus is shown in fig4 #di1 and briefly described in the ,chapter dealing with fossil ,bryophytes4 ,several species of ,flysch ,algae have recently been referred by ,rothpletz#cfg to the ,phaeophyceae under the provisional generic name ,phycopsis1 but they are of no special botanical interest4 ,the extremely interesting genus ,nematophycus has lately been assigned by a ,canadian author#cfh to a position in the ,phaeophyceae4 ,although the particular points on which he chiefly relies are not perhaps thoroughly established1 there are certain considerations which lead us to include ,nematophycus as a doubtful member of the present group of algae4 ,nematophycus4 ,the stem attains a diameter of between #b and #c feet in the largest specimens2 it is made up either of comparatively wide and loosely arranged tubes pursuing a slightly irregular vertical course accompanied by a plexus of much narrower tubes1 or of tubes varying in diameter but not divisible into two distinct types4 ,rings of growth occur in some forms but not in others4 ,radially elongated or isodiametric spaces occur in the stem tissues in which the tubes are less abundant4 ,reproductive organs unknown1 with the possible exception of some very doubtful bodies described as spores4 ,in #ahef ,sir ,william ,dawson proposed the generic name ,prototaxites for some large silicified trunks discovered in the ,lower and ,middle ,devonian rocks of ,canada4 ,a few years later the same writer#cfi published a detailed account of the new fossils and arrived at the conclusion that the ,devonian stem showed definite points of affinity with the recent genus ,taxus1 and the generic name suggests that he regarded it as the type of ,coniferous trees belonging to the sub-family ,taxineae4 ,the reasons for this determination were afterwards shown by ,carruthers to be erroneous4 ,dawson thought he recognised pits and spiral thickenings in the walls of the tubular elements1 as well as pointed ends in some of the latter4 ,the spiral markings were in reality small hyphal tubes passing obliquely across the face of the wider tubes1 and the apparent ends of the supposed tracheids were deceptive appearances due to the fact that the tubes had in some cases been cut through in an oblique direction4 ,in #ahgj ,carruthers#cgj expressed the opinion that ,dawson's ,prototaxites was a 8colossal fossil seaweed0 and not a coniferous plant4 ,the same author#cga in #ahgb published a full and able account of the genus1 and conclusively proved that ,prototaxites could not be accepted as a ,phanerogam2 he brought forward almost convincing evidence in favour of including the genus among the algae4 ,the name ,prototaxites was now changed for that of ,nematophycus4 ,carruthers compares the rings of growth in the fossil stems with those in the large ,antarctic ,lessonia stems1 but he regards the histological characters as pointing to the ,siphoneae as the most likely group of recent algae in which to include the ,palaeozoic genus4 ,we may pass over various notes and additional contributions by ,dawson1 who did not admit the corrections to his original descriptions which ,carruthers' work supplied4 ,in #ahhi an important memoir appeared by ,penhallow#cgb of ,montreal in which he confirmed ,carruthers' decision as to the algal nature of ,prototaxites2 he contributed some new facts to the previous account by ,carruthers1 and expressed himself in favour of regarding the fossil plant as a near ally of the recent ,laminariae4 ,the next addition to our botanical knowledge of this genus was made by ,barber#cgc who described a new specific type of ,nematophycus--,n4 ,storriei--found by ,storrie in beds of ,wenlock limestone age near ,cardiff4 ,solms-,laubach#cgd1 in a recent memoir on ,devonian plants1 recorded the occurrence of another species of this genus in ,middle ,devonian rocks near ,grfrath on the ,lower ,rhine4 ,lastly ,penhallow#cge1 in describing a new species1 lays stress on the resemblance of some of the tubular elements in the stem to the sieve-hyphae of the recent seaweeds ,macrocystis and ,laminaria4 ,he concludes that the new facts he records make it clear that ,nematophycus 8is an alga1 and of an alliance with the ,laminarias40 ,the recent evidence brought forward by ,penhallow is not entirely satisfactory2 the drawings and descriptions of the supposed trumpet-shaped sieve-hyphae are not conclusive4 ,on the whole it is probably the better course to speak of ,nematophycus as a possible ally of the brown algae rather than as an extinct type of the ,siphoneae1 but until our knowledge is more complete it is practically impossible to decide the exact position of this ,siluro-,devonian genus4 ,solms-,laubach#cgf has suggested that the generic name ,nematophyton1 used by ,penhallow in preference to ,carruthers' term ,nematophycus1 is the more suitable as being a neutral designation and not one which assumes a definite botanical position4 ,in view of the nature of the evidence in favour of the algal affinities of the fossil1 the reasons for discarding ,carruthers' original name are hardly sufficient4 ,before discussing more fully the distribution and botanical position of ,nematophycus we may describe at length one of the best known species1 and give a short account of some other forms4 #a4 ,nematophycus ,logani 7,daws474 ,fig4 #ci1 ,a-,e4 ,the stem possesses well marked concentric rings of growth due to a periodic difference in size of the large tubular elements4 ,the tissues consist of two distinct kinds of tubular elements1 the larger tubes loosely arranged and pursuing a fairly regular longitudinal course1 and having a diameter of #ac-ce2 the smaller tubes1 with a diameter of #e-f1 ramify in different directions and form a loose plexus among the larger and more regularly disposed elements4 ,branching occurs in both kinds of tubes2 septa have been recognised only in the smaller tubes4 ,irregular and discontinuous radial spaces traverse the stem tissues1 having a superficial resemblance in their manner of occurrence to the medullary rays of the higher plants4 ,the best specimens of this species were obtained by ,sir ,william ,dawson from the ,devonian ,sandstones of ,gasp in ,new ,brunswick4 ,the largest stems had a diameter of #c feet and reached a length of several feet#cgg2 in some examples ,dawson found lateral appendages attached to the stem which he described as 8spreading roots40 ,externally the specimens were occasionally covered with a layer of friable coal1 and internally the tissues were found to be more or less perfectly preserved by the infiltration of a siliceous solution4 ,most of the examples of ,nematophycus from ,britain and ,germany are much smaller and less perfectly preserved than those from ,canada4 ,the ,peter ,redpath ,museum1 ,montreal1 contains several very large blocks of ,nematophycus1 in many of which one sees the concentric rings of growth clearly etched out by weathering agents in a cross section of a large stem4 ,in fig4 #ci1 ,a1 a sketch is given of a thin transverse section of a stem1 drawn natural size4 ,the lines of growth are clearly seen1 and as in coniferous stems the breadth of the concentric zones varies considerably4 ,the short lines traversing the tissues in a radial direction represent the medullary-ray-like spaces referred to in the specific diagnosis4 ,a transverse section examined under a low-power objective presents the appearance of a number of thick-walled and comparatively wide tubes loosely arranged2 they may be in contact or separated from one another4 ,if the microscope be carefully focussed through the thickness of the section the transversely-cut tubes appear to move laterally1 producing a curiously dazzling effect if the objective is raised or lowered rapidly4 ,this lateral movement is due to the undulating vertical course of the tubes4 ,under a higher power the lighter-coloured matrix in which the tubes are embedded shows a number of very much smaller and thinner-walled hyphal elements2 some of these are cut across transversely1 others more or less obliquely and others again longitudinally4 ,these smaller tubes constitute an irregular plexus surrounding and ramifying between the larger elements4 ,the diameter of the larger tubes decreases for a certain distance in a radial direction as seen in a transverse section1 and this change in size gives rise to the appearance of concentric lines indicating periodic changes in growth4 ,illustration3 ,,fig4 #ci4 ,nematophycus ,logani 7,daws474 ,a4 ,part of a transverse section from a specimen in the ,british ,museum4 7,nat4 size47 ,b4 ,transverse section from specimens in ,mr ,barber's possession4 ,c4 ,longitudinal section4 7,b and ,c #afj47 ,d4 ,transverse section showing a radial space4 ,e4 ,transverse section2 a few #8cells' more highly magnified4 ,d and ,e from a specimen in the ,british ,museum4 ,the radial spaces are characterised by the partial absence of the larger tubes1 and as seen in longitudinal sections these spaces constitute regions in which the smaller tubes branch very freely4 ,fig4 #ci1 ,b1 represents a small piece of a transverse section seen under a fairly high power4 ,in fig4 #ci1 ,c1 the tubes are seen in longitudinal section4 ,the larger elements are unseptate and not very regular in their vertical course through the stem2 the smaller elements are seen as fine tubes lying between and across the larger tubes4 ,in the sections ,i have examined no undoubted transverse septa were detected in any of the tubular elements4 ,the question as to the possible connection between the larger and smaller elements is one which is not as yet satisfactorily disposed of4 ,penhallow#cgh regards the finer hyphal elements as branches of the larger tubes1 but ,barber#cgi1 who has carefully examined good material of ,nematophycus ,logani1 was unable to detect any organic connection between the two4 ,my own observations are in accord with those of ,barber4 ,further details and numerous figures of this species of ,nematophycus will be found in the memoirs of ,carruthers1 ,penhallow and ,barber4 ,some specimens of silicified ,nematophycus stems afford particularly instructive examples of the state of preservation or method of mineralisation as a source of error in histological work4 ,the sketches reproduced in fig4 #ci1 ,d and ,e1 were made from a section of a large specimen of ,nematophycus in the ,british ,museum4 ,in fig4 ,d we have one of the radial spaces containing some indistinct small elements1 the tissue surrounding the space appears to consist of polygonal cells suggesting ordinary parenchymatous tissue4 ,in fig4 ,e a few of these #8cells' are seen more clearly1 they have black and ragged walls1 and often contain very small and faint circles of which the precise nature is uncertain4 ,the true interpretation of this form of structure was first supplied by ,penhallow#chj4 ,the black network simulating parenchymatous tissue consists of the substance of ,nematophycus tubes which has been completely redistributed during fossilisation and collected along fairly regular lines1 as seen in figs4 ,d and ,e4 ,the original structure has been almost completely destroyed1 and the material composing the walls of the large tubes has finally been rearranged as a network1 interrupted here and there by the characteristic radial spaces which remain as evidence of the original ,nematophycus characters4 ,it is possible in some cases to trace every gradation from sections exhibiting the normal structure through those having the appearance shown in figs4 ,d and ,e to others in which the structure is completely lost4 ,penhallow describes this method of fossilisation in ,n4 crassus 7,daws472 an examination of several specimens in the ,national ,collection leads me to entirely confirm his general conclusions1 and also to the opinion that ,n4 ,logani shows exactly the same manner of mineralisation as ,n4 crassus4 ,the chief point of interest as regards this method of preservation lies in the fact that a fossil described by ,dawson#cha as ,celluloxylon primaevum1 and referred to as a probable conifer1 is undoubtedly a badly preserved ,nematophycus4 ,penhallow examined ,dawson's specimens and obtained convincing evidence of their identity with certain forms of highly altered ,nematophycus stems4 #b4 ,nematophycus ,storriei ,barber4 ,fig4 #dj4 ,the specimens on which ,barber#chb founded this species were obtained by ,mr ,storrie from the ,tymawr quarry near ,cardiff1 in beds of ,wenlock age4 ,the fragmentary nature of the material is largely compensated for by the excellence of the preservation4 ,we may briefly define the species as follows3 ,the stem consists of separate interlacing undivided and usually unbranched tubes of varying diameter4 ,spaces more or less isodiametric in dimensions are scattered through the tissue4 ,the spaces constitute regions in which the tubular elements branch freely4 ,the main distinguishing features of this ,british species are 7i7 the absence of two distinct and well-defined forms of tubular elements4 ,the main part of the stem consists of thick walled tubes similar to those of ,n4 ,logani1 but the spaces between them are occupied by thinner-walled and smaller tubes varying considerably in diameter2 7ii7 the form of the spaces which are not radially elongated as in ,n4 ,logani4 ,illustration3 ,,fig4 #dj4 ,nematophycus ,storriei ,barb4 ,longitudinal section1 from a photograph by ,mr ,c4 ,a4 ,barber4 #de4 ,fig4 #dj shows the undulating course of the tubes as seen in a longitudinal section2 the black colour of some of the elements is due to the fact that the surface of the wall is seen1 while in the lighter-coloured portions of the tubes the wall has been cut through4 ,the lighter patch about the middle of the figure shows the form of one of the spaces in which the tubes are freely branched4 ,in addition to the two species already described six others have been recorded1 but with these we need not concern ourselves in detail4 ,one of these species1 ,n4 ,hicksi1 was found by ,dr ,hicks#chc in the ,denbighshire grits quarry of ,pen-y-,glog near ,corwen in ,north ,wales4 ,the position of these beds has recently been determined by ,mr ,lake#chd as corresponding to that of the ,wenlock limestone4 ,this species and ,n4 ,storriei are both ,silurian examples of the genus4 ,it is possible1 as ,barber has suggested1 that the specimens described under these two names should be referred to one species4 ,the specimens found by ,hicks were small and imperfectly preserved fragments2 ,etheridge has given a full description of their structure1 and ,barber has subsequently examined the material4 ,the preservation is not such as will admit of any very precise specific diagnosis2 the fragments are correctly referred to ,nematophycus1 but their specific characters cannot be clearly determined4 ,solms-,laubach#che has described some fragments of another species of ,nematophycus from the ,devonian rocks of the ,lower ,rhine4 ,his specimens are chiefly interesting as extending the geographical range of the genus1 and as affording examples of a curious method of preservation4 ,the specimens obtained were small fragments1 flattened and very dark brown in colour4 ,the tubular elements consisted of an external membrane of black coal1 enclosing a central core of dark red iron-oxide4 ,on burning the fragment on a piece of platinum foil the coal composing the wall of the tubes was removed and the deep-red casts of the tube-cavities remained#chf4 ,the investigation of the structural characters of this imperfect material was conducted by reflected light4 ,under certain conditions1 when it is impossible to obtain thin sections for examination by transmitted light1 it is possible to accomplish much1 as shown by ,solms-,laubach's work1 by means of observation with direct light4 ,the last species to be noticed is ,nematophycus ,ortoni recently described by ,penhallow4 ,there are no concentric rings of growth1 no radial spaces and no smaller hyphae in the tissues of this type of stem4 ,in longitudinal section1 the tubes show occasional local expansions of the lumen which ,penhallow compares with the #8trumpet-hyphae' of some recent brown algae4 ,no actual sieve-plates or transverse walls have been detected1 but the general appearance of the tubes is considered to afford distinct evidence of the original existence of such walls4 ,the figures accompanying the description do not carry conviction as to the correctness of the reference of the tubes to imperfectly preserved sieve-hyphae4 ,the following list1 taken1 with a few alterations1 from ,penhallow's memoir#chg1 shows the geographical and geological range of the species of ,nematophycus hitherto recorded4 ,lower ,devonian of ,gasp4 ,nematophycus ,logani 7,daws47 ,silurian ,wenlock of ,england4 ,silurian of ,new ,brunswick4 ,n4 ,hicksi 7,eth47 ,silurian4 7,wenlock7 of ,n4 ,wales4 ,n4 crassus 7,daws47#chh ,middle ,devonian of ,gasp and ,new ,york4 ,n4 laxus 7,daws47 ,lower ,devonian of ,gasp4 ,n4 tenuis 7,daws47 ,lower ,devonian of ,gasp4 ,n4 ,storriei 7,barb47 ,silurian 7,wenlock7 of ,wales 7,cardiff74 ,n4 dechenianus 7,pied47 ,upper ,devonian of ,germany 7,grfrath74 ,n4 ,ortoni 7,pen47 ,upper ,erian of ,ohio4 ,in summing up our information as to the structure of ,nematophycus we find there are certain points not definitely settled1 and which are of considerable importance4 ,the few recorded instances of spore-like bodies by ,penhallow and ,barber are not satisfactory2 we are still ignorant of the nature of the reproductive organs4 ,such instances of lateral appendages as have been referred to do not throw much light on the habit of the plant4 ,so far as we know at present the stem of ,nematophycus was not differentiated internally into a cortical and central region4 ,it may be that the specimens have been only partially preserved1 and the coaly layer which occasionally surrounds a stem may represent a carbonised cortex which has never been petrified4 ,the large and loosely arranged tubes constitute the chief characteristic feature of the genus2 in some cases 7,n4 ,logani7 there is an accompanying plexus of smaller hyphae1 in others 7,n4 ,storriei7 there is no definite division of the tissue into two sets of tubes of uniform size1 and in ,n4 ,ortoni the tubular elements are all of the large type4 ,penhallow has recognised the branching of large tubes in ,n4 ,logani and ,n4 crassus giving rise to the small hyphal elements4 ,in most specimens1 however1 no such mode of origin of the smaller tubes can be detected4 ,the spaces which interrupt the homogeneity of the tissues in some forms have been described as branching depots1 on account of the frequent occurrence in these areas of much branched hyphae4 ,the function of these spaces 7fig4 #ci1 ,d1 and fig4 #dj7 may be connected with aeration of the stem-tissues4 ,as ,carruthers first pointed out the unseptate nature of the elements and the occurrence of large and small tubes forming a comparatively lax tissue suggested affinities with such recent genera as ,penicillus1 ,halimeda1 ,udotea and other members of the ,siphoneae4 ,in those fossil stems which possess tubes of two distinct sizes1 we cannot as a rule trace any organic connection between the two sets of tubular elements4 ,transverse septa have been detected in the tubes of some specimens of ,n4 ,logani4 ,these considerations and the large size and habit of growth of the stem leave one sceptical as to the wisdom of assigning the fossil genus to the ,siphoneae4 ,on the other hand1 apart from the doubtful sieve-hyphae of ,penhallow1 the manner of growth of the plant1 the concentric rings1 marked by a decrease in the diameter of the tubes1 the lax arrangement and irregular course of the elements1 afford points of agreement with some recent ,phaeophyceae4 ,the stem of a ,laminaria 7fig4 #bi7 or of a ,lessonia are the most obvious structures with which to compare ,nematophycus4 ,the medullary region of a ,laminaria or ,fucus and of other genera presents a certain resemblance to the tissues of the fossil stems4 ,on the whole we may be content to leave ,nematophycus for the present as probably an extinct type of alga1 more closely allied to the large members of the ,phaeophyceae than to any other recent seaweeds4 ,pachytheca4 7,a fossil of uncertain affinity47 ,there is another fossil occasionally associated with ,nematophycus and referred by many writers to the ,algae1 which calls for a brief notice4 ,pachytheca is too doubtful a genus to justify a detailed treatment in the present work4 ,although1 as ,i have elsewhere suggested#chi1 we are hardly in a position to speak with any degree of certainty as to its affinity1 it is not improbable that it may eventually be shown to be an alga4 ,without attempting a full diagnosis of the genus1 we may briefly refer to its most striking characters4 ,pachytheca usually occurs in the form of small spherical bodies1 about #e cm4 in diameter1 in ,old ,red ,sandstone or ,silurian rocks4 ,in section a single sphere is found to consist of two well marked regions2 in the centre1 of a number of ramifying and irregularly placed narrow tubes1 and in the peripheral or cortical region1 of numerous regular and radially disposed simple or forked septate tubes4 ,the tubular elements of the two regions are in organic connection4 ,the name was proposed by ,sir ,joseph ,hooker for some specimens found by ,dr ,strickland#cij in the ,ludlow bone-bed 7,silurian7 of ,woolhope and ,may-,hill4 ,examples were subsequently recorded from the ,wenlock limestone of ,malvern and from ,silurian and ,old ,red ,sandstone rocks of other districts4 ,hicks#cia found ,pachytheca in the ,pen-y-,glog grits of ,corwen in association with ,nematophycus1 and the two fossils have been found together elsewhere4 ,this association led to the suggestion that ,pachytheca might be the sporangium of ,nematophycus1 and ,dawson#cib1 in conformity with his belief in the coniferous character of the latter plant1 referred to ,pachytheca as a true seed4 ,the best sections of this fossil have been prepared with remarkable skill by ,mr ,storrie of ,cardiff2 they were carefully examined and described by ,barber in two memoirs#cic published in the ,annals of ,botany1 the account being illustrated by several well executed drawings and microphotographs4 ,among other difficulties to contend against in the interpretation of ,pachytheca there is that of mineralisation4 ,the preservation is such as to render the discrimination of original structure as distinct from structural features of secondary origin1 consequent on a particular manner of crystallisation of the siliceous material1 a matter of considerable difficulty4 ,suggestions as to the nature of ,pachytheca have been particularly numerous2 it has been referred to most classes of plants and relegated by some writers to the animal kingdom4 ,the most recent addition to our knowledge of this problematic fossil was the discovery of a specimen by ,mr ,storrie in which the ,pachytheca sphere rested in a small cup1 like an acorn fruit in its cupule4 ,this specimen was figured and described by ,mr ,george ,murray#cid in #ahie2 he expresses the opinion that the discovery makes the taxonomic position of the genus still more obscure4 ,solms-,laubach briefly refers to ,pachytheca in connection with ,nematophycus1 and regards its precise nature almost as much an unsolved riddle now as it was when first discovered4 ,for a fuller account of this fossil reference must be made to the contributions of ,hooker#cie1 ,barber#cif and others4 ,the literature is quoted by ,barber and more recently by ,solms-,laubach#cig4 ,there are several specimens and microscopic sections of ,pachytheca in the geological and botanical departments of the ,british ,museum4 ,the genus has been recorded from ,shropshire1 ,north ,wales1 ,malvern1 ,herefordshire1 ,perthshire and other ,british localities1 as well as from ,canada2 it occurs in both ,silurian and ,old ,red ,sandstone rocks4 ,algites4 ,a generic name for those fossils which in all probability belong to the class ,algae1 but which1 by reason of the absence of reproductive organs1 internal structure1 or characters of a trustworthy nature in the determination of affinity1 cannot be referred with any degree of certainty to a particular recent genus or family4 ,this term was suggested in #ahidcih as a provisional and comprehensive designation under which might be included such impressions or casts as might reasonably be referred to ,algae4 ,the practice of applying to alga-like fossils names suggestive of a definite alliance with recent genera is as a rule unsound4 ,it would simplify nomenclature1 and avoid the multiplication of generic names1 if the term ,algites were applied to such algal fossils from rocks of various ages as afford no trustworthy data by which their family or generic affinity can be established4 ,v4 ,,myxomycetes 7,,mycetozoa74 ,this class of organisms affords an interesting example of the impossibility of maintaining a hard and fast line between the animal and plant kingdom4 ,zoologists and ,botanists usually include the ,myxomycetes#cii in the text-books of their respective subjects1 and the name ,animal-fungi which has been applied to these organisms expresses their dual relationship4 ,they constitute one of three groups which we may include in that intermediate zone or #8buffer-state' between the two kingdoms4 ,from a palaeobotanical point of view the ,myxomycetes are of little interest1 but a very brief reference may be made to them rather for the sake of avoiding unnecessary incompleteness in our classification than from their importance as possible fossils4 ,they are organisms without chlorophyll1 consisting of a naked mass of protoplasm1 known as the plasmodium1 which may attain a size of several inches4 ,such plasmodia creep over the surface of decaying organic substrata1 and in forming their asexual reproductive cells they are converted into somewhat complex fruits containing spores4 ,the spores produce motile swarm-cells1 which eventually coalesce together to form a new plasmodium4 ,a few examples of fossil ,myxomycetes have been recorded from the ,palaeozoic and more recent formations1 but none of them are entirely beyond suspicion4 ,we may mention three examples of fossils referred to this group1 but only one of these is entitled to serious consideration4 ,myxomycetes ,mangini ,ren4#djj ,it is not uncommon to find distinct traces of original or secondary cell-contents in well preserved petrified plant-tissues4 ,there is often a difficulty1 however1 in distinguishing between the true cell-contents and the cells of some parasitic or saprophytic intruder4 ,in some petrified corky tissue in a silicified nodule from the ,permo-,carboniferous beds of ,autun1 ,renault has recently discovered what he believes to be traces of a ,myxomycetous plasmodium4 ,the cork-cells would be without protoplasmic contents of their own1 and their cavities contain a number of fine strands stretching from the cell-walls in different directions and uniting in places as irregular or more or less spherical masses4 ,the drawings given by ,renault of these irregular reticulated structures with scattered patches of what may possibly be petrified plasmodial protoplasm bear a striking resemblance to the plasmodium of a ,myxomycete4 ,a figure of the capillitium of a species of ,leocarpus figured by ,schrter#dja in his account of the ,myxomycetes in ,engler and ,prantl's work is very similar to that of ,renault's #8plasmodium4' ,it is by no means inconceivable that the ,myxomycetes ,mangini may be correctly referred to this group1 but the wisdom of assigning a name to such structures may well be questioned4 ,the other two examples call for little notice4 ,messrs ,cash and ,hick#djb in a paper on fossil fungi from the ,coal-,measures refer to some small spherical bodies as possibly the spores of a ,myxomycete4 ,they might be referred equally well to numerous other organisms4 ,gppert and ,menge#djc in their monograph on plants in the ,baltic ,tertiary ,amber1 express the opinion that an ill-defined tangle of threads which they figure may be a ,myxomycete4 ,it would serve no useful purpose to quote other instances of possible representatives of fossil ,mycetozoa2 but the consideration of the above examples may serve to emphasize the desirability of refraining from converting a possibility into an apparently recognised fact by the application of definite generic and specific names4 ,,vi4 ,,fungi4 ,the most striking difference between the fungi and algae is the absence of chlorophyll in the former1 and the consequent inability of fungi to manufacture their organic compounds from inorganic material4 ,fungi live therefore either as parasites or saprophytes1 and as the same species may pass part of its life in a living host to occur at another stage of its development as a saprophyte1 it is impossible to distinguish definitely between parasitic and saprophytic forms4 ,the vegetative body of a fungus1 that is the portion which is concerned with providing nourishment and preparing the plastic food-substance for the reproductive organs1 is known as the mycelium4 ,it consists either of a single and branched tubular cell known as a hypha1 or of several hyphae or thread-like elements 7filamentous fungi74 ,the hyphal filaments may be closely packed together and form a felted mass of compact tissue1 which in cross section closely simulates the parenchyma of the higher plants4 ,this pseudoparenchymatous form of thallus is particularly well illustrated by the so-called sclerotia2 these are sharply defined and often tuberous masses of hyphal tissue covered by a firm rind and containing supplies of food in the inner hyphae4 ,they are able to remain in a quiescent state for some time1 and to resist unfavourable conditions until germination and the formation of a new individual take place4 ,the reproductive structures assume various forms2 in some of the simpler fungi 7,phycomycetes7 sexual organs occur1 as in the parallel group of ,siphoneae among the algae1 but in the higher fungi the reproduction is usually entirely asexual4 ,an interesting case has recently been recorded among the more highly differentiated fungi in which distinct sexuality has been established#djd4 ,in addition to the reproductive organs1 such as oogonia and antheridia1 the asexual cells or spores are borne either in special sporangia1 or they occur as exposed conidia on supporting hyphae or conidiophores4 ,thick-walled and resistant resting-spores of various forms are also met with4 ,without going into further details we may very briefly refer to the larger subdivisions of this group of ,thallophytes4 ,,phycomycetes4 ,mycelium usually consisting of a single cell4 ,,zygomycetes1 ,reproduction by means of conidia1 and in many ,,oomycetes1 cases also by the conjugation of two similar including hyphae or by the fertilisation of an egg-cell ,chytridiaceae1 contained in an oogonium4 c4 ,,mesomycetes1 including the ,intermediate between the ,phycomycetes and ,sub-classes the higher fungi4 ,multicellular hyphae4 ,no ,,hemiasci and sexual organs4 ,,hemibasidii4 ,,mycomycetes4 ,septate vegetative mycelium4 ,no sexual including the reproduction--as a general rule4 ,asexual conidia ,sub-classes and other forms of spores4 ,in the ,ascomycetes ,,ascomycetes and the spores are found in characteristic ,,basidiomycetes4 club-shaped cases or asci2 in the ,basidiomycetes the spores are borne on special branches from swollen cells known as basidia4 ,the sporophore or spore-bearing body in this group may attain a considerable size 7e4g4 ,agaricus1 ,polyporus1 c47 and exhibit a distinct internal differentiation4 ,before describing a few examples of fossil fungi1 it is important to consider the general question of their manner of occurrence and determination4 ,considering the small size and delicate nature of most fungi1 it is not surprising that we have but few satisfactory records of well-defined fossil forms4 ,the large leathery sporophores of ,polyporus and other genera of the ,basidiomycetes1 which are familiar objects as yellow or brown brackets projecting from the trunks of diseased forest trees1 have been found in a fairly perfect condition in the ,cambridgeshire peat-beds1 and examples have been described also by continental writers#dje4 ,as a general rule1 however1 we have to depend on the chance mineralisation or petrifaction of the hyphae of a fungus-mycelium which has invaded the living or dead tissues of some higher plant4 ,in the literature on fossil plants there are numerous recorded species of fungi founded on dark coloured spots and blotches on the impression of a leaf4 ,most of such records are worthless2 the external features being usually too imperfect to allow of accurate identification4 ,the occurrence of recent fungi as discolourations on leaves is exceedingly common1 and the characteristic perithecia or compact and more or less spherical cases enclosing a group of sporangia in certain ,ascomycetous species1 might be readily preserved in a fossil condition4 ,sidenote3 ,,ascomycetes4 ,some examples of possible ,ascomycetous fungi have been recently recorded by ,potoni from leaves and other portions of plants of ,permian age4 ,there is a distinct superficial resemblance between the specimens he figures and the fructifications of recent ,ascomycetes1 but in the absence of internal structure1 it would be rash to do more than suggest the probable nature of the markings he describes4 ,for one of the fungus-like impressions ,potoni proposes the generic name ,rosellinites2 he compares certain irregularly shaped projections on a piece of ,permian wood with the perithecia of ,rosellinia1 a member of the ,sphaeriaceae1 and describes them as ,rosellinites ,beyschlagii ,pot4#djf ,various other records of similar ,ascomycetes-like fossils may be found in palaeobotanical literature#djg1 but it is unnecessary to examine these in detail4 ,unless we are able to determine the nature of the supposed fungus by microscopical methods our identifications cannot in most cases be of any great value4 ,an example of the perithecia of a fungus 7,rosellinia congregata ,beck7#djh has been recorded from the ,oligocene of ,saxony1 which would appear to rest on a more satisfactory basis than is often the case4 ,in this particular instance the small projections on a piece of fossil coniferous stem present a form which naturally suggests a fungus perithecium4 ,in cases where the black spots on a fossil stem or leaf possess a definite form and structure1 it is perfectly legitimate to refer them to a group of fungi2 but in very many instances the forms referred to such genera as ,sphaerites and others are of little or no value4 ,many forms of scale-insects and galls on leaves present an obvious superficial resemblance to epiphyllous fungi1 and might readily be mistaken for the fructifications of certain ,ascomycetous species4 ,as examples of scale-insects simulating fungi1 reference may be made to such genera of the ,coccineae as ,aspidiotus1 ,diaspis1 ,lecanium1 ,coccus1 and others4 ,the female insects lying on the surface of a leaf1 if preserved as a fossil impression1 might easily be mistaken for perithecia#dji4 ,another pitfall in fossil mycology may be illustrated by a description of a supposed fungus1 ,sclerotites ,salisburiae#daj1 ,mass4 on a ,tertiary ,ginkgo leaf4 ,the figure given by ,massalongo represents a ,ginkgo leaf with well marked veins1 the lamina between the veins being traversed by short discontinuous and longitudinally-running lines2 the latter are referred to as the fungus4 ,in a recent ,ginkgo leaf one may easily detect with the naked eye a number of short lines between and parallel to the veins1 which if examined in section are found to be secretory canals4 ,there can be little doubt that ,sclerotites ,salisburiae owes its existence to the preservation of these canals4 ,the list of fossil fungi given by ,meschinelli in ,saccardo's ,sylloge ,fungorum#daa includes certain species which are of no botanical value1 and should have no place in any list which claims to be authentic4 ,among the numerous examples of fossil #8fungi' which have no claim to be classed with plants1 there are some which are in all probability the galleries of wood-eating animals4 ,the radiating grooves frequently found on the inner face of the bark of a pine tree made by species of the beetle ,bostrychus might be mistaken for the impressions of the firm strands of mycelial tissue of some ,basidiomycetous fungus4 ,in some notes on fossil fungi by ,j4 ,f4 ,james#dab contributed to the ,american ,journal of ,mycology in #ahic1 it is pointed out that a supposed fungus described by ,lesquereux from the ,lower ,coal-,measures as ,rhizomorpha ,sigillariae#dac1 bears a strong likeness to some insect-burrows1 such as those of ,bostrychus4 8,a new fungus from the ,coal-,measures0 described by ,herzer in #ahicdad may probably be referred to animal agency4 ,in any case there is no evidence as to the fungoid nature of the object represented in the figure accompanying ,herzer's description4 ,sidenote3 ,,basidiomycetes4 ,more trustworthy evidence of fossil fungi is afforded by the marks of disease in petrified tissue and by the presence of true mycelia4 ,in examining closely the calcareous and siliceous plant-tissues from the ,coal-,measures and other geological horizons1 one occasionally sees fine thread-like hyphae ramifying through the cells or tracheal cavities2 in many cases the hyphae bear no reproductive organs and cannot as a rule be referred to a particular type of fungus4 ,if the hyphal filaments are unseptate1 they most likely belong to some ,phycomycetous species2 or if they are obviously septate the ,mesomycetes or the ,mycomycetes are the more probable groups4 ,occasionally there may be found indications of the characteristic clamp-connections in the septate filaments2 a small semicircular branch1 which is given off from a mycelium immediately above a transverse wall1 bends round to fuse with the filament just below the septum1 thus serving as a small loop-line connecting the cell-cavity above and below a cross wall4 ,such clamp-connections are usually confined to the hyphae of ,basidiomycetes and thus serve as a useful aid in identification4 ,a good example of a clamp-connection in a fossil mycelium is figured by ,conwentz#dae in his monograph on the ,baltic amber-trees of ,oligocene age4 ,the stout and thick type of hypha found in some fossil woods agrees closely with that of ,polyporus1 ,agaricus melleus and other well-known recent ,basidiomycetes4 ,in a section of a piece of lignified coniferous wood recently brought by ,col4 ,feilden from ,kolguev island#daf1 the brown and stout hyphae of a fungus are clearly seen as distinct dark lines traversing the tracheal tissue4 ,the occurrence of septa and the large diameter of the mycelial branches at once suggest a comparison with such recent forms as ,agaricus melleus1 ,polyporus and other ,basidiomycetes4 ,the age of the ,kolguev wood is not known with any certainty4 ,the vesicular swellings such as those represented in fig4 #da1 ,a1 ,b1 ,d and ,e1 may easily be misinterpreted4 ,such spherical expansions in a mycelium1 either terminal or intercalary1 may be sporangia1 oogonia or large resting-spores1 or non-fungal cell-contents1 and it is usually impossible in the absence of the contents to determine their precise nature4 ,hartig#dag and others have drawn attention to the occurrence of such bladder-like swellings in the mycelia of recent fungi1 which have nothing to do with reproductive purposes2 under certain conditions the hyphae of a fungus growing in the cavity of a cell or trachea may form such vesicles1 and these1 as in fig4 #db1 ,d1 m may completely fill up the cavity of a large tracheid4 ,some good examples of bladder-like swellings1 such as occur in the mycelium of ,agaricus melleus and other recent fungi1 have been figured by ,conwentz#dah in fossil wood of ,tertiary age from ,karlsdorf4 ,the swellings in this fossil fungus might easily be mistaken for oogonia or sporangia2 especially as they are few in number and spherical in form4 ,a similar appearance is presented by a mass of tyloses in the cavity of an old vessel or tracheid2 and vesicular cell-contents1 as in the cells of fig4 #da1 ,a1 #b-e1 may closely simulate a number of thin-walled fungal spores or sporangia4 ,a good example of such a vesicular tissue1 in addition to that already quoted1 is afforded by a specimen of an ,eocene fern1 ,osmundites ,dowkeri ,carr4#dai described by ,carruthers in #ahgj4 ,the ground-tissue cells contain traces of distinct fungal hyphae 7fig4 #da1 ,b71 and in many of the parenchymatous elements the cavity is completely filled with spherical vesicles2 in other cases one finds hyphae in the centre of the cell while vesicles line the wall1 as shewn in fig4 #da1 ,b4 ,carruthers refers to these bladders as starch grains1 and this may be their true nature2 their appearance and abundant occurrence in the parenchyma certainly suggest vesicular cell-contents rather than fungal cells4 ,i could detect no proof of any connection between the hyphae and bladders1 and the absence of the latter in the cavities of the tracheids1 fig4 #da1 ,c1 favoured the view of their being either starch-grains or other vacuolated contents similar to that in the cells of the ,portland ,cycad 7fig4 #da1 ,a7 referred to on p4 #hh4 ,sidenote3 ,,pathology ,,of ,,fossil ,,tissues4 ,the vacuolated cell-contents partially filling the cells in fig4 #da1 ,d1 present a striking resemblance to the contents of the cells #b-e in fig4 #da1 ,a4 ,in fig4 ,d the frothy and contracted substance might be easily mistaken for a parasitic or saprophytic fungus1 but this resemblance is entirely misleading4 ,it is by no means uncommon to find the cells of recent plants occupied by such vacuolated contents1 especially in diseased tissues in which a pathological effect produces an appearance which has more than once misled the most practised observers4 ,in the important work recently published by ,renault on the ,permo-,carboniferous flora of ,autun1 there is a small spore-like body described as a teleutospore1 and classed with the ,puccineae#dbj4 ,we have as yet no satisfactory evidence of the existence of this section of ,fungi in ,palaeozoic times1 and ,renault's description of ,teleutospora ,milloti from ,autun might be seriously misleading if accepted without reference to his figure4 ,the fragment he describes cannot be accepted as sufficient evidence for the existence of a ,palaeozoic ,puccinia4 ,the same author refers another ,palaeozoic fungus to the ,mucorineae under the name of ,mucor ,combrensis#dba2 this identification is based on a mycelium having a resemblance to the branched thallus of ,mucor1 but in the absence of reproductive organs such resemblance is hardly adequate as a means of recognition4 ,the occurrence of hyphal cells in calcareous shells and corals has already been alluded to4#dbb ,in addition to the examples referred to above1 there is one which has been described by ,etheridge#dbc from a ,permo-,carboniferous coral4 ,this observer records the occurrence of tubular cavities in the calices of ,stenopora crinita ,lonsd41 and attributes their origin to a fungus which he names ,palaeoperone endophytica2 he mentions one case in which a tube contains fine spherical spore-like bodies which he compares with the spores of a ,saprolegnia4 ,as pointed out above 7p4 #abh71 it is almost impossible to decide how far these tubes in shells and corals should be attributed to fungi1 and how far to algae4 ,illustration3 ,,fig4 #da4 ,a4 ,cells of ,cycadeoidea gigantea ,sew4 #cee4 ,b and ,c4 ,parenchymatous cells and scalariform tracheids of ,osmundites ,dowkeri ,carr4 #bcj4 ,d4 ,epidermal cells of ,memecylon 7,melastomaceae7 with vacuolated contents4 ,e4 ,peronosporites antiquarius ,smith1 7,no4 #aibc in the ,williamson collection74 #bcj4 ,f4 ,zygosporites4 #bcj4 7,a1 ,b1 ,c and ,e drawn from specimens in the ,british ,museum2 ,d from a drawing by ,prof4 ,marshall ,ward2 ,f from a specimen in the ,botanical ,laboratory ,collection1 ,cambridge47 ,illustration3 ,,fig4 #db4 ,a1 ,b1 ,c4 ,tracheids of coniferous wood attacked by ,trametes radiciperda ,hart4 7,polyporus annosus ,fr47 ,d and ,e4 ,tracheids attacked by ,agaricus melleus ,vahl4 ,a1 #fej1 ,b-,e1 #cfj4 7,after ,hartig47 ,passing from the direct evidence obtained from the presence of fungal hyphae in petrified tissues1 we must draw attention to the indirect evidence of fungal action afforded by many fossil plants4 ,it is important to be familiar with at least the more striking effects of fungal ravages in recent wood in order that we may escape some of the mistakes to which pathological phenomena may lead us in the case of fossils#dbd4 ,the gradual dissociation of the elements in a piece of fossil wood owing to the destruction of the middle lamellae1 the occurrence of various forms of slit-like apertures in the walls of tracheids 7fig4 #db1 ,e7 and the production of a system of fine parallel striation on the walls of a vessel are among the results produced by parasitic and saprophytic fungi4 ,with the help of a ferment secreted by its hyphae1 a fungus is able to eat away either the thickening cell layers or the middle lamellae or both1 and if1 as in fig4 #db1 ,a1 only the middle lamellae are left one might easily regard such tissue in a fossil condition as consisting of delicate thin-walled elements4 ,the oblique striae on the walls of a tracheid may often be due to the action of a ferment which has dissolved the membrane in such a manner as to etch out a system of spiral lines1 probably as a consequence of the original structure of the tracheids4 ,in distinguishing between the woods of ,conifers the presence of spiral thickening layers in the wood element is an important diagnostic character1 and it is necessary to guard against the confusion of purely secondary structures1 due to fungal action1 with original features which may be of value in determining the generic affinity of a piece of fossil wood4 ,oochytrium ,lepidodendri1 ,ren4 ,fig4 #dc1 #a4 ,under this name ,renault has recently described a filamentous fungus endophytic in the cavities of the scalariform tracheids of a ,lepidodendron#dbe4 ,the mycelium has the form of slender branched hyphae with transverse septa4 ,numerous ovoid and more or less spherical sporangia occur as terminal swellings of the mycelial threads4 ,the long axis of the ovoid forms measures #ab-ae 1 and the shorter axis #i-aj 2 the contents may be seen as a slightly contracted mass in the sporangial cavity4 ,in some of the sporangia one sees a short apical prolongation in the form of a small elongated papilla1 as shown in fig4 #dc1 #a4 ,renault refers this fungus to the ,chytridineae1 and compares it with ,cladochytrium1 ,woronina1 ,olpidium1 and other recent genera4 ,in the immediate neighbourhood of two of the sporangia shown in the uppermost tracheid of fig4 #dc1 #a1 there are seen a few minute dark dots which are described as spores petrified in the act of escaping from a lateral pore4 ,this interpretation strikes one as lacking in scientific caution4 ,the sporangia of ,hyphochytrium infestans#dbf1 as figured by ,fischer in ,rabenhorst's work bear a close resemblance to those of the fossil4 ,it would seem very probable that ,renault's species may be reasonably referred to the ,chytridineae1 as he proposes4 ,illustration3 ,,fig4 #dc4 #a4 ,oochytrium ,lepidodendri1 ,ren4 7,after ,renault47 #b4 ,polyporus vaporarius ,fr4 var4 succinea4 7,after ,conwentz47 #c4 ,cladosporites bipartitus ,fel4 7,after ,felix47 #d4 ,haplographites cateniger ,fel4 7,after ,felix47 ,peronosporites antiquarius ,w4 ,smith4 ,fig4 #da1 ,e4 ,in an address to the ,geologists' ,association delivered by ,mr ,carruthers in #ahgf a brief reference1 accompanied by a small-scale drawing1 is made to the discovery of a fungus in the scalariform tracheids of a ,lepidodendron from the ,english ,coal-,measures#dbg4 ,in the following year ,worthington ,smith published a fuller account of the fungus1 and proposed for it the above name#dbh1 which he chose on the ground of a close similarity between the mycelium and reproductive organs of the fossil form and recent members of the ,peronosporeae4 ,in ,smith's description the mycelium is described as bearing spherical swellings containing zoospores4 ,these spherical organs are fairly abundant and not infrequently met with in sections of petrified plant-tissues from the ,english ,coal-,measures2 they may be oogonia or sporangia1 or in some cases mere vesicular expansions of a purely vegetative hypha4 ,no confirmation has been given to the supposed spores referred to by ,smith4 ,prof4 ,williamson and others have carefully examined the specimens1 but they have failed to detect any trace of reproductive cells enclosed in the spherical sacs#dbi4 ,the mycelium does not appear to show any satisfactory evidence of its being septate as figured by ,smith4 ,the example shown in fig4 #da ,e has been drawn from one of the ,williamson specimens3 it illustrates the form and manner of occurrence of the characteristic swellings4 ,it is probable that some at least of the vesicles are either sporangia or oogonia1 but we cannot speak with absolute confidence as to their precise nature4 ,the general habit and structure of the fungus favour its inclusion in the class of ,phycomycetes4 ,the occurrence of several of the vesicles close together on short hyphal branches1 as shown in ,williamson's figures1 suggests the spherical swellings on vegetative hyphae1 but it is impossible to speak with absolute confidence4 ,there is a close resemblance between this ,english form and one recently described by ,renault as ,palaeomyces gracilis ,ren4#dcj2 the two fossils should probably be placed in the same genus4 ,the examples referred to below and originally recorded by ,cash and ,hick no doubt belong to the same type as ,smith's ,peronosporites4 ,the sketches reproduced in fig4 #dd have been drawn from specimens originally described by ,cash and ,hick in #ahghdca4 ,the sections were cut from a calcareous nodule from the ,halifax ,coal-,measures containing fragments of various plants and among others a piece of cortical tissue1 probably of a ,lepidodendron or ,stigmaria4 ,in a transverse section of this tissue one sees under a moderately high power that the cells have become partially separated from one another by the destruction of the middle lamellae 7fig4 #dd ,a74 ,the cell-cavities and the spaces between the isolated cells contain numerous fine fungal hyphae1 which here and there terminate in spherical swellings4 ,one such swelling is shown under a low power in fig4 #dd ,a1 in the middle uppermost cell1 and more highly magnified in fig4 #dd ,b4 ,in fig4 ,c there are two such swellings 7the larger one having a diameter of #jjc mm47 in contact1 but the connection does not appear to be organic4 ,the cell-walls of the infected tissue present a ragged and untidy appearance1 and in places 7e4g4 fig4 #dd ,d7 the membrane has been pierced by some of the mycelial branches4 ,illustration3 ,,fig4 #dd4 ,cells with fungal hyphae4 ,a4 ,a piece of disorganised tissue1 showing the separation of the cells4 ,b4 ,part of ,a more highly magnified4 ,c4 ,a single cell containing two swollen hyphae4 ,d4 ,partially destroyed cell-membranes pierced by fungal hyphae4 7,drawn from sections in the ,edinburgh ,botanical ,museum1 originally described by ,cash and ,hick47 ,this fungus bears a close resemblance to ,peronosporites antiquarius1 but it is impossible to determine its precise botanical position without further data4 ,in ,cash and ,hick's paper in which the above fungus is briefly dealt with1 some small spore-like bodies are figured which the authors speak of as possibly a ,myxomycetous fungus#dcb4 ,there is however no sound reason for such a supposition4 ,as examples of ,ascomycetous fungi found in silicified wood of ,tertiary age1 two species may be quoted from ,felix4 ,cladosporites bipartitus ,felix#dcc1 fig4 #dc1 #c4 ,the mycelium and conidia of this form were discovered in some ,eocene silicified wood from ,perekeschkul near ,baku1 on the shores of the ,caspian4 ,the conidia are elliptical or pyriform in shape and divided by a transverse septum into two cells4 ,no traces were found of any special conidiophores4 ,the mycelium consists of septate branched hyphae1 rendered conspicuous by a brown colouration4 ,felix compares the fossil with the recent genera ,cephalothecium and ,cladosporium4 ,haplographites cateniger ,felix#dcd1 fig4 #dc1 #d4 ,the conidia of this form were found to be fairly abundant in the silicified tissue investigated by ,felix2 they occur usually in chains of #b to #f conidia having an ovoid or flask-shaped form1 with a thick membrane 7fig4 #dc1 #d74 ,the mycelium consists of branched hyphae divided into long cylindrical cells by transverse septa2 occasional instances were found of an ,h-shaped fusion between lateral branches of parallel hyphae4 ,felix compares this species with examples of the genera ,haptographium and ,dematium of the family ,sphaeriaceae2 it was found in the woody tissue of a dicotyledonous stem from ,perekeschkul4 ,zygosporites sp4 ,the object represented in fig4 #da ,f consists of a stalked spherical sac bearing a number of radiating arms which are divided distally into delicate terminations4 ,we find similar bodies figured by ,williamson#dce in his ,i,xth and ,xth ,memoirs on the ,coal-,measure plants2 he includes some of them under the generic term ,zygosporites1 and compares them with the zygospores of the freshwater algae ,desmideae4 ,hitherto these spore-like fossils have only been recorded as isolated spheres1 but in the example shown in fig4 #da ,f there is a distinct tubular and thin-walled stalk attached to the ,zygosporites4 ,the specimen was found in the partially disorganised cortical tissue of a ,lyginodendron stem from the ,english ,coal-,measures4 ,it is difficult to decide as to the precise nature of the fossil1 but the presence of the hyphal stalk points to a fungus rather than an alga as the most probable type of plant with which to connect it4 ,it may possibly be a sporangium of a fungus comparable with the common mould ,mucor1 or it may be a zygospore formed by the conjugation of two hyphae of which only one has been preserved4 ,sidenote3 ,,polyporus4 ,for an example of a fossil representative of the ,basidiomycetes we may turn to the excellent monograph by ,conwentz on the ,baltic amber trees1 and quote one of the forms which he has described4 ,polyporus vaporarius ,fr4 f4 succinea#dcf1 fig4 #dc1 #b4 ,in several preparations of the wood preserved by petrifaction in amber ,conwentz found distinct indications of the ravages of a fungus1 which suggested the presence of the recent species ,polyporus vaporarius ,fr4 ,with the help of the indirect evidence afforded by the pathological effects as seen in the tissues of the host-plant1 and the direct evidence of the fungal mycelium ,conwentz was led to this identification4 ,the mycelium is brown in colour1 in part thick-walled1 and in part with thin walls1 transversely septate and not much branched4 ,in the portion of one of ,conwentz' figures reproduced in fig4 #dc1 #b1 the rents and holes in the tracheid walls are clearly shown2 they afford the indirect evidence of fungal attacks1 and are of the same nature as those shown in fig4 #db1 ,b1 ,c and ,e4 ,enough has been said to call attention to the paucity of exact data on which to generalise as to the geological history of fungi4 ,the types selected for description or passing allusion have not been chosen in each case because of their special intrinsic value1 but rather as convenient examples by which to illustrate authentic records or to serve as warnings against possible sources of error4 ,it would seem that we have fairly good and conclusive evidence of the existence in ,permo-,carboniferous times of ,phycomycetous fungi1 but it is not until we pass to post-,palaeozoic or even ,tertiary plants that we discover satisfactory representatives of the higher fungi or ,mycomycetes4 ,if special attention were paid to the investigation of fossil fungi1 it is quite possible that our knowledge of the past history of the group might be considerably extended4 ,it is essential that the greatest caution should be exercised in the identification of forms and in their reference to definite families2 otherwise our lists of fossil species will serve to mislead1 and to emphasize the untrustworthy character of palaeobotanical data4 ,unless we feel satisfied as to the position of a fossil fungus it is unwise to use a generic term suggestive of a definite family or recent genus4 ,such a name as ,renault has used in one instance1 ,palaeomyces1 might be employed as a useful and comprehensive designation4 ,,vii4 ,,charophyta4 ,,charace4 ,,nitelle4 ,it has been the general custom to include the ,charace or ,stoneworts among the ,chlorophyceae 7green algae71 of which they form a distinctly isolated family4 ,on the whole1 it would seem better to follow the course lately adopted by ,migula#dcg and allow the ,charace to rank as a family of a distinct group1 ,charophyta4 ,while agreeing in many respects with plants higher in the scale than ,thallophytes1 the ,stoneworts do not sufficiently resemble the ,bryophyta to be included in that group4 ,the ,charophyta are plants containing chlorophyll1 living in fresh and brackish water2 the stem is jointed1 and bears at the nodes whorls of leaves1 on which are borne the reproductive organs4 ,the antheridia are spherical in shape and of complex structure1 containing numerous biciliate antherozoids4 ,the oogonia are oval in form and contain a single large egg-cell4 ,the ,chara-plant is developed from a protonema formed from the germinating oospore4 ,vegetative reproduction is effected by means of bulbils1 accessory shoots1 etc4 ,the ,nitelle have not been recognised in a fossil condition4 ,the absence or feeble development of a calcareous incrustation renders the genera of this family less likely to be preserved than such a genus as ,chara4 ,chareae4 ,leaves and stems with or without a cortical investment4 ,fruit with a five-celled corona4 ,the envelope of the #8fruit' and other parts of the plant are frequently encrusted with carbonate of lime4 ,in the genus ,chara1 the best known member of the family1 the plant as a whole resembles in its general habit and external differentiation of parts the higher plants4 ,the stem consists of long internodes separated by short nodes bearing whorls of leaves4 ,each internode consists of a long cylindrical cell1 which becomes enclosed by a cortical sheath composed of rows of cells which have grown upwards and downwards from the peripheral nodal cells4 ,the cortical cells are usually spirally twisted and impart to the stem a characteristic appearance2 they are divided by transverse walls into numerous cells some of which occasionally grow out into short processes 7fig4 #de c74 ,the leaves repeat on a smaller scale the structural features of the stem1 but possess a limited growth1 whereas the stem has an unlimited power of growth by means of a large hemispherical apical cell4 ,branches arise in the axils of the leaves4 ,the plants are either monoecious or dioecious4 ,the oogonium is elliptical in shape1 and is borne on a short stalk-cell1 it contains a single oosphere4 ,the wall of the oogonium is formed of five spirally twisted cells which have grown over it from the five peripheral cells of a leaf-node4 ,the tips of the investing cells project at the apex in the form of a terminal crown or corona 7fig4 #de1 ,e1 c74 ,the antheridia have a complex structure1 and produce a very large number of motile antherozoids4 ,illustration3 ,,fig4 #de4 ,a and ,b4 ,chara ,knowltoni ,sew4 ,from a section in the ,british ,museum4 ,c4 ,stem of ,chara foetida ,a4 ,br4 in transverse section 7after ,migula4 #ah74 ,d4 ,interior of oogonium of ,c4 foetida4 ,e4 ,oogonium of ,c4 foetida 7,d and ,e after ,migula4 #ej74 ,after fertilisation1 the egg-cell becomes surrounded by a membrane1 at first colourless1 but afterwards yellow or brown4 ,the inner cell-walls of the cells surrounding the oospore become thicker and darker in colour2 the outer walls remain thin and eventually fall away4 ,the lateral walls may or may not become thickened4 ,in most of the ,chareae a calcareous deposit is formed between the hard shell and the outer walls of the cells enveloping the oospore4 ,this calcareous shell is developed subsequently to the thickening and hardening of the inner walls of the fruit-case4 ,the cells of the corona and stalk do not become calcareous4 ,in the fossil ,charas1 it is this calcareous shell that is preserved4 ,in the members of the ,chareae the stems are usually encrusted with carbonate of lime1 and thus have a much better chance of preservation than the slightly calcareous ,nitelle4 ,chara4 ,the generic characters have already been described in the brief account of the family ,chareae4 ,the generic name was proposed by ,vaillant in #agaidch1 and adopted by ,linnaeus1 who classed the ,stoneworts with aquatic phanerogams4 ,as long ago as #afbcdci a figure of ,chara was published by ,caspar ,bauhin as a form of ,equisetum4 ,the generic name ,chara has usually been applied to recent and fossil species alike4 ,the existing species have a wide distribution2 ,chara foetida1 ,a4 ,br41 a common ,british form1 occurs in practically all parts of the world4 ,stems and calcareous #8fruit-cases' occur fairly commonly in a fossil state1 and differ but little from recent species1 at least as regards essential features4 ,it is difficult to say at what geological horizon the ,stoneworts are first represented4 ,the first certain traces of ,chara occur in ,jurassic rocks1 but certain spirally marked subspherical bodies have been recorded from ,devonian and ,carboniferous strata1 which closely resemble ,chara oogonia1 and may be ,palaeozoic representatives of the genus4 ,in #ahhi ,mr ,knowlton#ddj of the ,american ,geological ,survey described some #8problematic organisms' found in ,devonian rocks at the falls of the ,ohio4 ,examples of these fossils are shown in fig4 #df b and c2 the spirally grooved body measures from #aej to #ahj mm4 in diameter1 and about #agj mm4 in length4 ,the ,chara-like character of the fossils had been previously suggested by ,meek#dda in #ahgc4 ,without going into the arguments for or against placing these fossils in the ,chareae1 they may at least be mentioned as possible but not certain ,palaeozoic forms of ,chara or an allied genus4 ,illustration3 ,,fig4 #df4 a4 ,chara ,bleicheri ,sap4 #cj4 b and c4 ,devonian ,chara8 sp4 circa #ab4 d and e4 ,chara ,wrighti ,forbes4 circa #ab4 #a4 ,chara ,bleicheri1 ,saporta4 ,fig4 #df1 a4 ,in this form the #8fruits' are minute and subspherical1 #ci-dd mm4 long1 and #ce-dj mm4 broad1 showing in side view #e-f slightly oblique spiral bands4 ,each spiral band bears a row of slightly projecting tubercles4 ,this species was first described by ,saporta#ddb from the ,oxfordian 7,jurassic7 rocks of the ,department of ,lot in ,france2 it is compared by the author of the species with ,chara ,jaccardi ,heer1 described by ,heer from the ,upper ,jurassic rocks of ,switzerland4 #b4 ,c4 ,knowltoni1 ,seward4 ,fig4 #de1 a and b1 and ,fig4 #dg4 ,the ,oogonia are broadly oval1 about #emm4 in length1 and at the broadest part of about the same breadth4 ,the surface is marked by eleven or twelve bands in the form of a flattened spiral4 ,the stems possess investing cortical cells4 ,this species was founded on specimens from the ,wealden beds of ,sussex#ddc1 but numerous examples of ,chara #8fruits' and stems have long been known from the uppermost ,jurassic rocks of the ,dorset coast and the ,isle of ,wight1 which may probably be included in this species4 ,these fossil ,charas are abundant#ddd in the ,chert beds of ,purbeck age seen in the cliffs near ,swanage4 ,pieces of corticated stems from this locality are represented in fig4 #de ,a and ,b4 ,the cortical cells surrounding a large internodal cell are very clearly seen in the section shown in fig4 #de ,b1 and in the longitudinal view in fig4 #de ,a4 ,the resemblance of these specimens to the stems of recent ,stoneworts is very striking4 ,illustration3 ,,fig4 #dg4 ,chara ,knowltoni1 ,sew4 #cj4 ,the single oogonium of fig4 #dg was found in the ,wealden beds near ,hastings4 #c4 ,chara ,wrighti1 ,forbes4 ,fig4 #df1 d and e4 ,this species is characterised by globular or somewhat elliptical oogonia1 with six or seven spiral bands4 ,it is very abundant in the ,lower ,headon beds of ,hordwell ,cliffs on the ,hampshire coast#dde4 ,various species of ,chara are commonly met with in the ,oligocene beds of the ,isle of ,wight and ,hampshire1 as well as in the ,paris basin beds1 and elsewhere4 ,well preserved #8fruits' and stem fragments are met with in a siliceous rock of ,upper ,oligocene age imported from ,montmorency in the ,paris basin1 and used as a stone for grinding phosphates at some chemical works near ,upware1 a few miles from ,cambridge4 ,many other species of fossil ,charas are known from various horizons and localities1 but the above examples suffice as illustrative types4 ,in ,post-,tertiary deposits masses of ,chara and plant fragments occasionally occur forming blocks of ,travertine4 ,examples of such ,chara beds have been recorded by ,sharpe from ,northampton#ddf1 by ,lyell#ddg from ,forfarshire1 and by other writers from several other districts4 ,beds of calcareous marl are occasionally seen as whitish streaks in the peat of the ,fenland#ddh2 these often consist in great part of ,charas4 ,a season's growth of ,chara in a shallow lake or mere in the ,fens may appear as a white line in a section of peaty and other material which has been formed on the site of old pools or lakes4 ,the recognition of specific characters in the isolated ,chara #8fruits' usually met with in a fossil state is exceedingly unsatisfactory2 the features usually relied on in the living species are not preserved1 and great care should be taken in the separation of the various forms4 ,,chapter ,,viii4 ,,bryophyta 7,muscineae74 ,i4 ,,hepaticae 7,liverworts74 ,,ii4 ,,musci 7,mosses74 ,the ,bryophyta are small plants1 varying in size from #a mm4 to about #cj cm41 creeping or erect1 having a thalloid1 or more usually a foliose body1 consisting of a cell-mass exhibiting in most cases a distinct internal differentiation4 ,they possess no true roots and no true vascular tissue4 ,the life-history of the members of the group is characterised by a well-marked and definite alternation of generations4 ,the ,moss or ,liverwort plant is the sexual generation 7gametophyte71 and as a result of the fertilisation of an egg-cell the asexual or spore-bearing generation 7sporophyte7 is produced4 ,the sporophyte never exhibits a differentiation into stem and leaves4 ,asexual and vegetative reproduction are effected by means of spores1 bulbils1 or detached portions of the plant-body4 ,sexual reproduction is by means of biciliate antherozoids produced in antheridia and egg-cells formed singly in archegonia4 ,in the ,bryophytes the distinguishing characteristics are more constant and well-defined than in the ,thallophytes4 ,in the former the plant never consists of a single cell or coenocyte1 but is always multicellular1 and exhibits in most cases a definite physiological division of labour as expressed in the histological differentiation of distinct tissue-systems4 ,in the ,thallophytes there is no true alternation of generation in the same sense as in the ,mosses and ,liverworts and in the higher plants4 ,in the ,bryophytes the sexual reproduction has reached a higher stage of development and a much greater constancy as regards the nature of the reproductive organs4 ,on the germination of the spore there is usually formed a fairly distinct structure known as the protonema1 from which the ,moss or ,liverwort developes as a bud#ddi4 ,,marchantiales4 ,i4 ,,hepaticae4 ,,anthocerotales4 ,,jungermanniales4 ,the vegetative plant-body possesses a different organisation on the ventral and dorsal side2 it has the form of a thalloid creeping plant 7,thalloid ,liverworts71 or of a delicate stem with thin appendages or leaves without a midrib 7,foliose ,liverworts74 ,in most cases the body of the plant is made up of parenchymatous tissue1 showing but little internal differentiation2 in one or two genera a few strengthening or mechanical fibres occur among the thinner walled ground-tissue4 ,on the germination of the spore1 a feebly developed protonema is produced1 which gives rise to the ,liverwort plant4 ,reproduction as in the group ,bryophyta4 ,sidenote3 ,,determination ,,of ,,liverworts4 ,the ,liverworts have a very wide geographical distribution1 and are specially abundant in moist shady situations2 they grow on stones or damp soil1 and occur as epiphytes on other plants4 ,marchantia1 ,pellia1 and ,jungermannia are among the better known ,british representatives of the class4 ,considering the soft nature of the body of recent ,liverworts1 it is not surprising that they are poorly represented in a fossil state4 ,in the absence of the sexual reproductive organs1 or of the sporophytes1 which have scarcely ever been preserved1 exact identification is almost hopeless4 ,the difficulties already referred to in dealing with the algae1 as regards the misleading similarity between the form of the thallus and the bodies of other plants1 have to be faced in the case of the ,liverworts4 ,many of the thalloid ,liverworts1 if preserved in the form of a cast or impression without internal structure or reproductive organs1 could hardly be distinguished from various genera of algae in which the thallus has the form of a forked plate-like body4 ,such genera as ,pellia1 ,marchantia1 ,lunularia1 ,reboulia1 and others bear a striking resemblance to ,fucus1 ,chondrus and many other algae4 ,imperfect specimens of certain ,lichens1 not to mention some of the ,polyzoa1 might easily be mistaken for ,liverworts4 ,among the higher plants1 there are some forms of the ,podostemaceae which simulate in habit both thalloid and foliose ,liverworts as well as ,mosses#dej4 ,the members of this ,dicotyledonous family are described as water-plants with a ,moss- or ,liverwort-like form2 they occur on rocks in quickly-flowing water in the tropics4 ,in one instance a recent ,podostemaceous genus has been described as a member of the ,anthocerotales2 the genus ,blandowia#dea1 referred to by ,willdenow as a ,liverwort1 has since been recognised as one of the ,podostemaceae4 ,the resemblance between some of the foliose ,hepaticae and genera of ,mosses is often very close4 ,in certain ,mosses1 such as ,hookeria pennata#deb1 the large two-ranked leaves suggest the branches of a ,selaginella4 ,illustration3 ,,fig4 #dh4 ,a4 ,tristichia hypnoides ,spreng4 ,from a specimen in the ,british ,museum4 ,b4 ,podocarpus cupressina ,br4 and ,ben4 7,after ,brown and ,bennett#dec47 ,c4 ,selaginella ,oregana ,eat4 ,from a plant in the ,cambridge ,botanic ,garden4 ,a1 ,b and ,c very slightly reduced4 ,the plant reproduced in fig4 #dh ,a 7,tristichia71 one of the ,podostemaceae1 might easily be mistaken for a foliose ,liverwort if found as a fragmentary fossil4 ,such species of ,selaginella as ,s4 ,oregana ,eat4 and ,s4 rupestris ,spring 7fig4 #dh ,c7 have a distinctly moss-like habit and do not present a very obvious resemblance to the more typical and better known ,selaginellas4 ,the twig of a ,podocarpus 7,p4 cupressina7#ded in fig4 #dh ,b affords an instance of a conifer which simulates to some extent certain of the larger-leaved ,liverworts2 it bears a resemblance also to some fossil fragments referred to ,selaginellites or ,lycopodites4 ,a small fossil specimen figured by ,nathorst#dee from ,japan as possibly a ,lycopodites may be compared with a coniferous twig1 and with some of the larger ,liverworts1 e4g4 species of ,plagiochila#def4 ,podocarpus cupressina is1 however1 chiefly instructive as an example of the striking differences which are met with among species of the same genus2 it differs considerably from the ordinary species of ,podocarpus1 and might well be identified as a member of some other group than that of the ,coniferae4 ,we have no records of ,palaeozoic ,hepaticae4 ,the fossils which ,zeiller has figured in his ,flore de ,brive as ,schizopteris dichotoma ,gmb4#deg and ,s4 trichomanoides ,gpp4 bear a resemblance to some forms of hepatics1 but there is no satisfactory evidence for removing them from the position assigned to them by the ,french writer4 ,in ,mesozoic rocks a few specimens are known which bear a close resemblance as regards the form of the thalloid body to recent ,liverworts1 but the identification of such fossils cannot be absolutely trusted4 ,two ,french authors1 ,,mm4 ,fliche and ,bleicher#deh1 have described a plant from ,lower ,oolite rocks near ,nancy as a species of ,marchantia1 ,m4 oolithus1 but they point out the close agreement of such forked laminar structures to algae and lichens4 ,from ,tertiary and ,post-,tertiary beds a certain number of fossil species have been recorded1 but they possess no special botanical interest4 ,,order ,,marchantiales4 ,the plant-body is always thalloid1 bearing rhizoids on the lower surface1 and having an epidermis with pores limiting the upper or dorsal surface4 ,marchantites4 ,this convenient generic name was proposed by ,brongniart in #ahdidei2 it may be briefly defined as follows3 ,vegetative body of laminar form1 with apparently dichotomous branches1 and agreeing in habit with the recent thalloid ,hepaticae1 as represented by such a genus as ,marchantia4 ,the name ,marchantites is preferable to ,marchantia1 as the latter implies identity with the recent genus1 whereas the former is used in a wide sense and refers rather to a definite form of vegetative body than to a particular generic type4 #a4 ,marchantites erectus 7,leckenby74 ,fig4 #di4 ,this species may be described as follows3 ,the thalloid body is divided into spreading dichotomously branched segments1 obtusely pointed apically4 ,the slightly wrinkled surface shows a distinct and comparatively broad darker and shorter median band1 with lighter coloured and thinner margins4 ,illustration3 ,,fig4 #di4 ,marchantites erectus 7,leck474 ,from the type-specimen in the ,woodwardian ,museum4 ,nat4 size4 ,in #ahfd ,leckenby described this plant from the ,lower ,oolite beds of the ,yorkshire coast near ,scarborough1 as ,fucoides erectus1 regarding it as a fossil alga4 ,i recently pointed out that the general appearance and mode of occurrence of the specimens suggest a liverwort rather than an alga1 and proposed the substitution of the genus ,marchantites#dfj4 ,it would1 however1 be unwise to speak with any great confidence as to the real affinities of the fossil4 ,the example shown in the figure is the type-specimen of ,leckenby#dfa3 the breadth of the branches is about #c mm4 ,under a low magnifying power the surface shows distinct and somewhat oblique wrinklings1 the general appearance being very similar to that of some recent forms of the genus ,marchantia4 ,a closely allied species has recently been described from the ,wealden beds of ,ecclesbourne1 near ,hastings1 on the ,sussex coast1 as ,marchantites ,zeilleri ,sew4#dfb4 ,in a recent monograph on ,jurassic plants from ,poland1 apparently containing much that is of the greatest value1 but which is unfortunately written in the ,polish language1 ,raciborski#dfc describes a new species of thalloid ,liverwort under the name of ,paleohepatica ,rostafinski4 ,the specimens are barren plants larger than any ,jurassic species hitherto described2 they agree closely in habit with ,saporta's ,tertiary species ,marchantites ,sezannensis4 #b4 ,marchantites ,sezannensis ,saporta4 ,fig4 #ej4 ,the body is broadly linear and dichotomously branched1 with a somewhat undulating margin4 ,midrib on the dorsal surface depressed1 but more prominent on the ventral surface4 ,the upper surface is divided into hexagonal areas1 in each of which occurs a central pore4 ,there are two rows of scales along the median line on the lower surface4 ,stalked male receptacles4 ,brongniart#dfd first mentioned this fossil hepatic1 which was found in the calcareous travertine of ,szanne of ,oligocene age in the ,province of ,marne4 ,the specimens figured by ,saporta#dfe show very clearly the characters of one of the ,marchantiaceae1 and in this case we have the additional evidence of the characteristic male receptacles which are given off from a point towards the apex of the lobes1 and arise from a slight median depression4 ,in one of ,saporta's figures 7reproduced in fig4 #ej ,a7 there are represented some median scars which may mark the position of cups similar to those which occur on recent species of ,marchantia1 and in which gemm or bulbils are produced4 ,illustration3 ,,fig4 #ej4 ,marchantites ,sezannensis ,sap4 ,a4 ,surface view of the thallus2 g1 8 cups with gemm4 ,b4 ,a male branch4 ,c4 ,a portion of ,a magnified to show the surface features4 7,after ,saporta47 ,the collection of ,szanne fossils in the ,sorbonne includes some very beautiful casts of ,marchantites in which the structural details are preserved much more perfectly than in the examples described by ,saporta4 ,in a few specimens which ,prof4 ,munier-,chalmas recently showed me the reproductive branches were exceedingly well shown4 ,the fossils occur as moulds in the travertine1 and the museum specimens are in the form of plaster-casts taken from the natural moulds4 ,several species of ,liverworts belonging to the ,marchantiales and ,jungermanniales have been recorded from the amber of ,north ,germany1 of ,oligocene age4 ,these appear to be represented by small fragments1 such as are figured by ,gppert and ,berendt#dff in their monograph on the amber plants1 published in #ahde4 ,the determinations have since been revised by ,gottsche#dfg1 who recognises species of ,frullania1 ,jungermannia1 and other genera4 ,,sphagnales4 ,,ii4 ,,musci4 ,,andreaeales4 ,,bryales4 ,the plant-body 7gametophyte7 in the ,musci consists of a stem bearing thin leaves1 usually spirally disposed1 rarely in two rows4 ,the internal differentiation of the stem is generally well marked1 and in some cases is comparable in complexity with the structure of the higher plants4 ,a protonema arises from the spore1 having the form of a branched filamentous1 or more rarely a thalloid structure4 ,reproduction as in the group ,bryophyta4 ,mosses like ,liverworts have an extremely wide distribution1 and occur in various habitats4 ,in many districts vast tracts of country are practically monopolised by peat-forming genera1 such as ,sphagnum and other ,mosses4 ,some genera are found on rocks at high altitudes in dry regions1 a few grow as saprophytes1 and many occur either as epiphytes on the leaves and stems of other plants1 or carpeting the ground under the shade of forest trees4 ,sidenote3 ,,determination ,,of ,,mosses4 ,in the simpler ,mosses1 the stem consists of a parenchymatous ground-tissue with a few outer layers of thicker-walled and smaller cells4 ,in others there is a distinct central cylinder which occupies the axis of the stem1 and consists of long and narrow cells2 in the more complex forms the structure of the axial tissues suggests the central cylinder or stele of higher plants4 ,the genus ,polytrichum1 so abundant on ,english moors1 illustrates this higher type of stem differentiation4 ,in a transverse section of the stem the peripheral tissue is seen to be composed of thick-walled cells1 passing internally into large parenchymatous tissue4 ,the axial part is occupied by a definite central cylinder consisting in the centre of elongated elements with dark-coloured and thick walls having thin transverse septa2 surrounding this central tissue there are thinner walled elements1 of which some closely agree in form with the sieve-tubes of the higher plants4 ,the central tissue may be regarded as a rudimentary type of xylem1 and the surrounding tissue as a rudimentary phloem4 ,each leaf is traversed by a median conducting strand which passes into the stem and eventually becomes connected with the axial cylinder4 ,the fertilisation of the egg-cell gives rise to the development of a long slender stalk terminating distally in a large spore-capsule4 ,in section the stalk or seta closely resembles the leafy axis of the moss plant4 ,considering the fairly close approach of some of the mosses to the higher plants as regards histological characters1 it is conceivable that imperfectly petrified stems of fossil mosses might be mistaken for twigs of ,vascular ,cryptogams4 ,like ,liverworts1 ,mosses have left very few traces of their existence in plant-bearing rocks4 ,without the aid of the characteristic moss-#8fruit' or sporogonium it is almost impossible to recognise fossil moss-plant fragments4 ,in species of the tropical genera ,spiridens and ,dawsonia1 e4g4 ,s4 longifolius#dfh ,lind4 or ,d4 superba#dfi ,grev4 and ,d4 polytrichoides#dgj ,r4 ,br41 the plant reaches a considerable length1 and resembles twigs of plants higher in the scale than the ,bryophytes4 ,the finer branches of species of the extinct genus ,lepidodendron are extremely moss-like in appearance4 ,again1 ,cyathophyllum bulbosum ,muell#dga1 with its two kinds of leaves arranged in rows1 is not at all unlike species of ,selaginella or the hepatic genus ,gottschea4 ,it is by no means improbable that some of the ,palaeozoic specimens described as twigs of ,lycopodites1 ,selaginites1 or ,lepidodendron1 may be portions of mosses4 ,the fertile branches of ,lycopodium phlegmaria in a fossil condition might be easily mistaken for fragments of a moss4 ,in some conifers with small and crowded scale-leaves there is a certain resemblance to the stouter forms of moss stems4 ,such possible sources of error should be prominently kept in view when we are considering the value of negative evidence as regards the geological history of the ,musci4 ,a recent writer#dgb on mosses has expressed the opinion that no doubt the ,musci played an exceedingly important rle in past time4 ,although we have no proof that this was so1 yet it is far from improbable1 and the absence of fossil mosses must no doubt be attributed in part to their failure to be preserved in a fossil state4 ,in the numerous samples of ,coal-,measure vegetation preserved in extraordinary perfection in the calcareous nodules of ,england1 no certain trace of a moss has so far been discovered4 ,the most delicate tissue in the larger ,palaeozoic plants has often been preserved1 and in view of such possibilities of petrifaction it might appear strange that if moss-like plants existed no fragments had been preserved4 ,their absence is1 however1 no proof of the non-existence of ,palaeozoic mosses1 but it is a fact which certainly tends towards the assumption that mosses were probably not very abundant in the ,coal ,period forests4 ,epiphytic mosses frequently occur on the stems and leaves of ferns and other plants in tropical forests4 ,such small and comparatively delicate plants would1 however1 be easily rubbed off or destroyed in the process of fossilisation1 and it is extremely rare to find among petrified ,palaeozoic plants the external features well preserved4 ,it is probable that the forests extended over low lying and swampy regions1 and that1 in part1 the trees were rooted in a submerged surface4 ,under such conditions of growth there would not be the same abundance of ,bryophytes as in most of our modern forests4 ,to whatever cause the absence of mosses may be best attributed1 it is a fact that should not be too strongly emphasised in discussions on plant-evolution4 ,muscites4 ,this comprehensive genus may be defined as follows3-- ,stem filiform1 simple or branched1 bearing small sessile leaves1 with a delicate lamina1 without veins or with a single median vein1 arranged in a spiral manner on the stem4 ,muscites#dgc is one of those convenient generic designations which limited knowledge and incomplete data render necessary in palaeontology4 ,fossil plants which in their general habit bear a sufficiently striking resemblance to recent mosses1 may be included under this generic name4 ,illustration3 ,,fig4 #ea4 ,muscites polytrichaceus ,ren4 and ,zeill4 7after ,renault and ,zeiller74 #a4 ,muscites polytrichaceus ,renault and ,zeiller4 ,in this species the stems are about #c-d cm4 long and #ac m4 broad1 usually simple1 but sometimes giving off a few branches1 and marked externally by very delicate longitudinal grooves4 ,the leaves are alternate1 closely arranged1 lanceolate1 with an acute apex1 gradually narrowed towards the base1 #a-b mm4 long1 traversed by a single median vein4 ,one of the ,french specimens1 on which the species was founded#dgd1 is shown in fig4 #ea1 and the form of the leaves is more clearly seen in the small enlarged piece of stem4 ,the authors of the species point out that the tufted habit of the specimens1 their small size1 and the membranous character of the leaves1 all point to the ,musci as the ,class to which the plant should be referred in spite of the absence of reproductive organs4 ,among recent mosses1 the genus ,rhizogonium1--one of the ,mniaceae1--and ,polytrichum are spoken of as offering a close resemblance to the fossil form4 ,the type-specimen was found in the ,coal-,measures of ,commentry1 and is now in the ,museum of the cole des ,mines in ,paris2 the figure given by ,,mm4 ,renault and ,zeiller faithfully represents the appearance of the plant4 ,it has been suggested#dge that some small twigs figured by ,lesquereux#dgf from the ,coal-,measures of ,north ,america as ,lycopodites ,meeki ,lesq41 may possibly be mosses4 ,the specimens do not appear to be at all convincing1 and cannot well be included as probable representatives of ,palaeozoic ,musci4 ,lycopodites ,meeki ,lesq4 bears a close resemblance to the recent ,selaginella ,oregana shown in fig4 #dh1 ,c4 ,from ,mesozoic rocks we have no absolutely trustworthy fossil mosses4 ,the late ,prof4 ,heer#dgg has quoted the occurrence of certain fossil ,caterpillars in ,liassic beds as indicative of the existence of mosses1 but evidence of this kind cannot be accepted as scientifically sound4 ,in #ahej ,buckman#dgh described and figured a few fragments of plants from a freshwater limestone at the base of the ,lias series near ,bristol4 ,among others he described certain specimens as examples of a fossil ,monocotyledon1 under the generic name ,najadita4 ,mr ,starkie ,gardner#dgi subsequently examined the specimens1 and suggested that the ,lias fragments referred to ,najadita should be compared with the recent freshwater moss ,fontinalis4 ,in this opinion he was supported by ,mr ,carruthers and ,mr ,murray of the ,british ,museum4 ,in a footnote to the memoir in which this suggestion is made1 ,gardner refers to a moss-capsule from the same beds1 which he had received from ,mr ,brodie4 ,through the kindness of the latter gentleman1 ,i have had an opportunity of examining the supposed capsule1 and have no hesitation in describing it as absolutely indeterminable4 ,it is in the form of an irregularly oval brown stain on the surface of the rock1 with the suggestion of a stalk at one end1 but there are no grounds for describing the specimen as a moss-capsule1 or indeed anything else4 ,the type-specimens figured by ,brodie and subsequently referred to a moss are now in the ,british ,museum2 they are small and imperfect fragments of slender stems bearing rather long oval leaves which might well have belonged to a moss4 ,the material is however too fragmentary to allow of accurate diagnosis or determination4 #b4 ,muscites ferrugineus 7,ludg474 ,this species possesses a slender stem bearing crowded ovate-acuminate leaves4 ,the capsules are cup-shaped1 borne on a short stalk1 with a circular opening without marginal teeth4 ,this fossil was first figured and described by ,ludwig#dhj from a brown ironstone of ,miocene age at ,dernbach in ,nassau4 ,the author of the species placed it in the recent genus ,gymnostomum1 and ,schimper#dha afterwards changed the generic name to ,sphagnum1 at the same time altering the specific name to ,ludwigi4 ,the evidence is hardly strong enough to justify a generic designation which implies identity with a particular recent genus1 and it is a much safer plan to adopt the non-committal term ,muscites1 at the same time retaining ,ludwig's original specific name4 ,without having examined the type-specimen it is impossible to express a definite opinion as to the accuracy of the description given by ,ludwig2 if the capsule is correctly identified it is the oldest example hitherto recorded of a fossil moss-sporogonium4 ,,chapter ,,ix4 ,,pteridophyta 7,vascular ,cryptogams74 ,the ,pteridophytes include plants which vary in size from a few millimetres#dhb to several metres in height4 ,the spore on germination gives rise to a small thalloid structure1 the prothallium1 on which the sexual organs are developed2 this is the gametophyte or sexual generation4 ,the sexual organs have the form of typical archegonia and antheridia4 ,from the fertilised egg-cell there is developed the ,pteridophyte plant or sporophyte1 which bears the spores4 ,this asexual generation shows a well-marked external differentiation into stem and leaves1 and bears true roots4 ,internally the tissues exhibit a high degree of differentiation into distinct tissue-systems4 ,true vascular bundles occur1 which may or may not be capable of secondary thickening by means of a cambium1 i4e4 a definitely localised zone of meristematic tissue4 ,the sporangia are borne either on the ordinary foliage leaves or on special spore-bearing leaves called sporophylls1 which differ in a greater or less degree from the sterile leaves4 ,the majority of the best known and most important ,palaeozoic genera are either true ,vascular ,cryptogams1 or possess certain of the pteridophytic characteristics combined with those of higher plants4 ,it is not merely the commoner and more familiar recent genera with which the student of extinct types must be acquainted1 but it is extremely important that he should make himself familiar with the rarer1 less known and more isolated recent forms1 which often throw most light on the affinities of the older representatives of the group4 ,it is often the case1 the more isolated living plants are1 the more likely are they to afford valuable assistance in the interpretation of genera representing a class1 which reached its maximum development in the earlier periods of the earth's history4 ,the importance of paying special attention to such recent plants as may be looked upon as survivals of a class now tending towards extinction1 will be more thoroughly realised after the extinct vascular cryptogams have been dealt with4 ,a comparison of the ,pteridophyta and ,bryophyta brings out certain points of divergence4 ,in the first place1 the sporophyte assumes in the former class a much more prominent rle1 and the gametophyte has suffered very considerable reduction4 ,the gametophyte1 i4e4 the structure which is formed on the germination of the asexually-produced spore1 is usually short-lived1 small1 and more or less dependent on the sporophyte for its nutrition4 ,in a few cases only is it capable of providing itself with the essential elements of food4 ,on the other hand1 the sporophyte1 at a very early stage of its development becomes free from the gametophyte and is entirely self-supporting4 ,reproduction is effected as in the ,bryophyta by sexual reproductive organs and by asexual methods4 ,not only have we in the ,pteridophytes a much more complete external division of the plant-body into definite members1 which subserve distinct functions1 and behave as well-defined physiological organs adapted for taking a certain share in the life-functions of the individual1 but the internal differentiation has reached a much higher stage4 ,true vascular tissue1 consisting of xylem and phloem1 occurs for the first time in this class4 ,the whole plant is traversed by one or more vascular strands composed of xylem and phloem elements1 which are respectively concerned with the distribution of inorganic and organic food substances4 ,the ,pteridophyta include the most important fossil plants4 ,it is from a study of the internal structure of various extinct representatives of this class1 that palaeobotanists have been able to contribute facts of the greatest interest and importance towards the advancement of botanical science4 ,the botanist's chief aim in the anatomical investigation of ,palaeozoic genera is to discover data which point the way to a solution of the problems of plant-evolution4 ,in the abundant material afforded by the petrified remnants of ancient floras we have the means of tracing the past history of existing groups or individual forms1 and it is from the ,palaeozoic ,pteridophytes that our most valuable results have been so far obtained4 ,in this and the following chapters of ,volume ,i4 two divisions of the ,pteridophyta are dealt with in such detail as the nature of the book allows4 ,in the earlier chapters of ,volume ,,ii4 the remaining representatives of this class will be described4 ,as in the preceding chapters such recent plants will be described as are most essential for the correct interpretation of the fossil forms4 ,it is impossible to do more than confine our attention to a few only of the genera of living plants which directly concern us2 some acquaintance with the general facts of plant morphology must be assumed4 ,among the most useful text-books or books of reference on the ,pteridophyta the student may consult those mentioned in the footnote#dhc4 ,i4 ,,equisetales4 ,leaves usually small in proportion to the size of the whole plant1 arranged in whorls at the nodes4 ,sporangia borne on specially modified sporophylls or sporangiophores1 which are aggregated to form a definite strobilus or spore-bearing cone4 ,,equisetaceae4 7,recent ,species47 ,the leaves are in whorls1 coherent in the form of a sheath1 and traversed by longitudinal veins which do not fork or anastomose4 ,the stem is divided into comparatively long internodes separated by the leaf-bearing nodes1 and the branches arise in the leaf-axils at the nodes4 ,the fertile leaves or sporophylls differ from the sterile leaves1 and usually occur in definite aggregations or strobili containing spores of one kind 7isosporous74 ,in the single living genus ,equisetum1 the outer coat of the mature spore forms two hygroscopically sensitive filamentous structures or elaters4 ,on the germination of the spore the gametophyte is developed in the form of a small lobed prothallium #a-b cm4 in length4 ,in most cases there are distinct male and female prothallia4 ,the genus ,equisetum ,l41 the common ,horse-tail1 is the sole living representative of this ,family4 ,it occurs as a common native plant in ,britain1 and has a wide geographical distribution4 ,species of ,equisetum are abundant in the temperate zones of both hemispheres1 and occur in arctic as well as tropical latitudes4 ,wallace#dhd speaks of ,horse-tails1 8very like our own species10 growing at a height of #ejjj feet on the ,pangerango mountain in ,java4 ,in favourable situations the large ,british ,horse-tail1 ,equisetum maximum ,lam4 7 ,e4 ,telmateia ,erhb471 occasionally reaches a height of about six feet1 and growing in thick clusters forms miniature forests of trees with slender erect stems and regular circles of long and thin branches4 ,a tropical species1 ,equisetum giganteum ,linn4#b living in the marshes of ,mexico and ,cuba#dhe1 and extending southward to ,buenos ,ayres and ,chili1 reaches a height of twenty to forty feet1 but the stem always remains slender1 and does not exceed an inch in diameter4 ,groves of such tall slender plants on the eastern slopes of the ,andes#dhf suggest to the palaeobotanist an enfeebled forest-growth recalling the arborescent ,calamites of a ,palaeozoic vegetation4 ,the twenty-five existing species of ,equisetum are remnants of various generic types of former epochs1 and possess a special interest from the point of view of the geological history of plants4 ,a brief description of the main characters of the recent genus will enable the student to appreciate the points of difference and agreement between the extinct and present representatives of the ,equisetales4 ,illustration3 ,,fig4 #eb4 ,equisetum maximum ,lam4 ,a4 ,fertile shoot with strobilus and sterile leaf-sheaths after ,luerssen 7#hi72 slightly less than nat4 size4 ,b4 ,sporophyll bearing open sporangia 7after ,luerssen2 slightly enlarged74 ,c4 ,part of a transverse section 7diagrammatic72 v1 vallecular canals1 e1 endodermis1 c1 carinal canals 7after ,luerssen2 #bj74 ,d4 ,equisetum arvense ,l4 ,part of a transverse section of an internode of a sterile shoot4 v1 cortex1 e1 endodermis1 x1 xylem tracheids1 a remains of annular tracheids of the protoxylem1 c1 carinal canal 7after ,strasburger2 #ij74 ,equisetum4 ,the plant consists of a perennial underground creeping rhizome1 branching into secondary rhizomes1 divided into well-marked nodes and internodes4 ,from the nodes are given off two sets of buds1 which may develope into ascending aerial shoots or descending roots4 ,at each node is a leaf-sheath more or less deeply divided along the upper margin into teeth representing the tips of coherent leaves 7fig4 #eb1 ,a74 ,in some species one or more internodes of underground branches become considerably swollen and assume the form of ovate or elliptical starch-storing tubers1 which are capable of giving rise to new plants by vegetative reproduction4 ,tubers1 either singly or in chains1 occur in ,e4 arvense ,linn41 ,e4 sylvaticum ,linn41 ,e4 maximum ,lam41 among ,british species4 ,illustration3 ,,fig4 #ec4 ,rhizome 7,r7 of ,equisetum palustre ,l4 with a thin shoot giving off roots and tuberous branches from a node after ,duval-,jouve 7#fd74 ,in the example shown in fig4 #ec 7,equisetum palustre ,l4#dhg7 the stout rhizome ,r gives off from its node1 marked by a small and irregular leaf-sheath1 two thin roots and a single shoot4 ,the latter has a leaf-sheath at its base1 and from the second node1 with a larger leaf-sheath1 there have been developed branches with tuberous internodes2 the constrictions between the tubers and the tips of the terminal tubers bear small leaf-sheaths4 ,branched roots are also given off from the upper node of the erect shoot4 ,near the surface of the ground the buds on the rhizome nodes develope into green erect shoots4 ,the shoot axis is marked out into long internodes separated by nodes bearing the leaf-sheaths4 ,the surface of each internode is traversed by regular and more or less prominent longitudinal ridges and grooves2 each ridge marking the position of an internal longitudinal vascular strand4 ,in the axil of each leaf1 that is in the axil of each portion of a leaf-sheath corresponding to a marginal uni-nerved tooth1 there is produced a lateral bud which may either remain dormant or break through the leaf-sheath and emerge as a lateral branch4 ,at the base of each branch an adventitious root may be formed from a cell immediately below the first leaf-sheath1 but in aerial shoots the roots usually remain undeveloped4 ,the lateral branches repeat on a smaller scale the general features of the main axis4 ,in some species1 the shoots are unbranched1 and in others the slender branches arise in crowded whorls from each node4 ,leaves1 roots and branches are given off in whorls1 and the whorls from each node alternate with those from the node next above and next below4 ,sidenote3 ,,anatomy ,,of ,,equisetum4 ,in some species of ,equisetum the aerial stem terminates in a conical group of sporophylls1 while in others the strobilus is formed at the apex of a pale-coloured fertile shoot1 which never attains any considerable length and dies down early in the season of growth 7fig4 #eb1 ,a74 ,below the terminal cone or strobilus there occur one or two modified leaf-sheaths4 ,such a ring of incompletely developed leaves intervening between the cone of sporangiophores and the normal leaves1 is known as the annulus4 ,the annulus is seen in fig4 #eb1 ,a1 immediately below the lowest whorl of sporophylls2 it has the form of a low sheath with a ragged margin4 ,in the region of the cone the internodes remain shorter1 and the whorls of appendages1 known as sporophylls or sporangiophores1 have the form of stalked structures terminating distally in a hexagonal peltate disc1 which bears on its inner face a ring of five to ten oval sporangia 7fig4 #eb1 ,b74 ,each sporangium contains numerous spores which eventually escape by the longitudinal dehiscence of the sporangial wall4 ,the opening of the sporangia is probably assisted by the movements of the characteristic elaters formed from the outer wall of each spore4 ,the spores1 which are capable of living only a short time1 grow into aerial green prothallia1 #a-b cm4 in length2 these have the form of irregularly and more or less deeply lobed structures4 ,on the larger and more deeply lobed prothallia the archegonia or female reproductive organs are borne1 and the smaller or male prothallia bear the antheridia4 ,on the fertilisation of an egg-cell1 the ,equisetum plant is gradually developed4 ,for a short time parasitic on the female prothallium or gametophyte1 the young plant soon takes root in the ground and becomes completely independent4 ,as seen in transverse section through a young stem near the apex1 the axis consists of a mass of parenchyma1 in which may be distinguished a central larger-celled tissue1 surrounded by a ring of smaller-celled groups marking the position of a circle of embryonic vascular strands4 ,in each young vascular strand1 a few of the cells next the pith may be seen to have thicker walls and to be provided with a ring-like internal thickening2 these have passed over into the condition of annular tracheids and represent the protoxylem elements4 ,at a later stage1 a transverse section through the stem shows a central hollow pith1 formed by the tearing apart and subsequent disappearance of the medullary parenchymatous cells1 which were unable to keep pace with the growth in thickness of the stem4 ,the pith cavity is bridged across at each node by a multi-layered plate of parenchyma1 which forms the so-called nodal diaphragm4 ,the inner edge of each vascular strand is now found to be occupied by a small irregularly circular canal 7fig4 #eb1 ,c1 c1 and ,d1 c7 in which may be seen some of the rings of protoxylem tracheids 7,d1 a7 which have been torn apart and almost completely destroyed4 ,these canals1 known as carinal canals1 have arisen by the tearing and disruption of the thin-walled cells in the immediate neighbourhood of the protoxylem4 ,each carinal canal is bounded by a layer of elongated parenchymatous cells which form part of the xylem of the vascular bundle1 and is succeeded internally by the general ground-tissue of the stem4 ,the xylem parenchyma next a carinal canal is succeeded externally by phloem tissue1 consisting of short protoplasmic cells and longer elements1 without nuclei and poor in contents2 the latter may be regarded as sieve-tubes4 ,on either side of the phloem1 the xylem occurs in two separate bands or groups of annular and reticulately thickened tracheids4 ,in some species1 e4g4 ,equisetum xylochaetum ,metten4#dhh and ,e4 giganteum#dhi ,l4 a native of ,south ,america1 the xylem has the form of two bands composed of fairly numerous tracheids1 but in most species the xylem tracheids occur in small groups1 as shown in the figure of ,e4 maximum 7fig4 #eb1 ,d74 ,in the shape of the vascular bundle1 and in the formation of the carinal canal1 there is a distinct resemblance between the vascular bundles of ,equisetum and those of a monocotyledonous stem4 ,these collateral stem-bundles of xylem and phloem traverse each internode as distinct strands1 and at the nodes each strand forks into two branches 7fig4 #ed1 ,a71 which anastomose with the alternating bundles passing into the stem from the leaf-sheath4 ,thus the vascular strands of each internode alternate in position with those of the next internode4 ,illustration3 ,,fig4 #ed4 ,a4 ,plan of the vascular bundles in the stem of an ,equisetum2 b1 branches passing out to buds 7after ,strasburger72 l1 vascular strands passing to the leaf-segments4 ,b4 ,longitudinal section through a node of ,e4 arvense ,l4 7after ,duval-,jouve2 #bj74 ,explanation in the text4 ,there are certain points connected with the vascular bundles in the nodal region of a shoot1 which have an important bearing on the structure of fossil equisetaceous stems4 ,fig4 #ed ,b represents a diagrammatic longitudinal section through the node of a rhizome of ,equisetum arvense from which a root h is passing off in a downward direction1 and a branch in an upward direction4 ,the black band c in the parent stem shows the position of the vascular strands2 in the region of the node the vascular tissue attains a considerable thickness1 as seen at d in the figure4 ,the bands passing out to the left from d go to supply the branch and root respectively4 ,the increased breadth of the xylem strands at the node is due to the intercalation of a number of short tracheids4 ,fig4 #ee1 #d shows a transverse section through a mature node of ,equisetum maximum2 px marks the position of the protoxylem and e that of the endodermis4 ,on comparing this section with that of the internodal vascular bundle in fig4 #eb1 ,d1 the much greater development of wood in the former is obvious2 the carinal canal of the internodal bundle is absent in the section through a node4 ,the disposition of the xylem tracheids in fig4 #ee1 #d shows a certain regularity which1 though not very well marked1 suggests the development of wood elements as the result of cambial activity4 ,longitudinal sections through the nodal region demonstrate the existence of 8cells similar to those of an ordinary cambium1 and a cell-formation resulting from their division which is similar to that in an ordinary secondary thickening40#dij ,the short tracheids which make up this nodal mass of xylem differ from those in the internodal bundle in their smaller size1 and in being reticulately thickened4 ,there is1 therefore1 evidence that in the nodes of some ,equisetum stems additional xylem elements are produced by a method of growth comparable with the cambial activity which brings about the growth in thickness of a forest-tree#dia4 ,the significance of these statements will be realised when the structure of the extinct genus ,calamites is described and compared with that of ,equisetum4 ,the small drawing in fig4 #ee1 #c shows part of the ring of thick nodal wood2 the section cuts through two bundles about their point of bifurcation1 the strand x is passing out in a radial direction to a lateral branch1 the strand to the right of x and the separate fragment of a strand to the left of x are portions of leaf-trace bundles on their way to the leaf-sheath4 ,reverting to fig4 #ed1 ,b1 the other structures seen in the section are the leaf-sheaths 7l and m71 the vallecular canal 7f71 the epidermis1 cortex and pith 7k1 e and a7 of the stem4 ,the epidermis which has been ruptured by the root and branch is indicated at i1 i2 the dotted lines traversing the upper part of the pith of the lateral branch mark the position of a nodal diaphragm4 ,illustration3 ,,fig4 #ee4 #a4 ,transverse section of a root of ,equisetum variegatum ,schl41 e endodermis1 or outer layer of the phloeoterma 7after ,pfitzer2 #afj74 #b4 ,transverse section of rhizome of ,e4 maximum1 slightly enlarged4 #c4 ,transverse section through a node of ,e4 maximum1 x1 branch of vascular strand 7slightly enlarged74 #d4 ,transverse section through a node of ,e4 maximum showing the mass of xylem1 px protoxylem 7 #age74 7,figs4 #c and #d after ,cormack47 ,immediately external to each vascular strand1 as seen in transverse section1 there is a layer of cells containing starch1 and this is followed by a distinct endodermis1 of which the cells show the characteristic black dot in the cuticularised radial walls 7fig4 #eb1 ,d74 ,beyond the endodermis there is the large-celled parenchyma of the rest of the cortex4 ,tannin cells occur here and there scattered among the ground tissue4 ,on the same radius on which each vascular strand occurs1 the cortical parenchyma passes into a mass of sub-epidermal thick-walled mechanical tissue or stereome4 ,alternating with the ridges of stereome1 the grooves are occupied by thin-walled chlorophyll-containing tissue which carries on most of the assimilating functions1 and communicates with the external atmosphere by means of stomata arranged in vertical rows down each internode4 ,the continuity of the cortical tissue is interrupted by the occurrence of large longitudinal vallecular canals alternating in position with the stem ridges and vascular strands 7fig4 #eb1 ,c1 v74 ,the epidermis consists of a single layer of cells1 containing stomata1 and with the outer cell-walls impregnated with silica4 ,in certain species of ,equisetum1 e4g4 ,e4 palustre ,l41 the whole circle of vascular strands is enclosed by an endodermis1 and has the structure typical of a monostelic stem4 ,in others e4g4 ,e4 litorale ,khl4 each vascular strand is surrounded by a separate endodermis1 and in some forms e4g4 ,e4 sylvaticum ,l4 there is an inner as well as an outer endodermal layer#dib4 ,without discussing the explanation given to this variation in the occurrence of the endodermis1 it may be stated that in all species of ,equisetum the stem may be regarded as monostelic#dic4 ,in the rhizome the structure agrees in the main with that of the green shoots1 but the vallecular canals attain a larger size1 and the pith is solid4 ,a slightly enlarged transverse section of a rhizome of ,equisetum maximum is shown in fig4 #ee1 #b1 the small circles surrounding the pith mark the position of the vascular bundles and carinal canals2 the much larger spaces between the central cylinder and the surface of the stem are the vallecular canals4 ,the central cylinder or stele of the root is of the diarch1 triarch or tetrarch type2 i4e4 there may be #b1 #c or #d groups of protoxylem in the xylem of the root stele4 ,the axial portion is occupied by large tracheids1 and the smaller tracheids of the xylem occur as radially disposed groups1 alternating with groups of phloem4 ,external to the xylem and phloem strands there occur two layers of cells1 usually spoken of as a double endodermis1 but it has been suggested that it is preferable to describe the double layer as the phloeoterma#did1 of which the inner layer has the functions of a pericycle1 and the outer that of an endodermis4 ,a transverse section of a root is seen in fig4 #ee1 #a1 the dark cells on the left are part of a thick band of sclerenchyma in the cortex of the root1 the layer e is the outer layer of the phloeoterma4 ,without describing in detail the development#die of the sporangia1 it should be noted that the sporangial wall is at first #c to #d cells thick1 but it eventually consists of a single layer4 ,the cells have spiral thickening bands on the ventral surface1 and rings on the cells where the longitudinal splitting takes place4 ,each sporangium is supplied by a vascular bundle which is given off from that of the sporangiophore axis4 ,the strobili are isosporous4 ,a4 ,,equisetites4 ,b4 ,,phyllotheca4 ,,ii4 ,,fossil ,,equisetales4 ,c4 ,,schizoneura4 ,d4 ,,calamites4 ,e4 ,,archaeocalamites4 ,in dealing with the fossil ,equisetales1 we will first consider the genera ,equisetites1 ,phyllotheca and ,schizoneura1 and afterwards describe the older and better known genera ,calamites and ,archaeocalamites4 ,a thoroughly satisfactory classification of the members of the ,equisetales is practically impossible without more data than we at present possess4 ,it has been the custom to include ,equisetites1 ,phyllotheca and ,schizoneura in the family ,equisetaceae1 and to refer ,calamites and ,archaeocalamites to the ,calamarieae2 such a division rests in part on assumption1 and cannot be considered final4 ,when we attempt to define the ,equisetales and the two families ,equisetaceae and ,calamarieae1 we find ourselves seriously hampered by lack of knowledge of certain important characters1 which should be taken into account in framing diagnoses4 ,there is little harm in retaining provisionally the two families already referred to1 if we do not allow a purely arbitrary classification to prejudice our opinions as to the affinities of the several members of the ,equisetales4 ,the ,equisetaceae might be defined as a family including plants which were usually herbaceous but in some cases arborescent1 bearing verticils of leaves in the form of sheaths more or less deeply divided into segments or teeth4 ,the strobili were isosporous and consisted of a central axis bearing verticils of distally expanded sporophylls with sporangia1 as in ,equisetum4 ,the genus ,equisetites might be included in this family1 but it must be admitted that we know next to nothing as to its anatomy1 and we cannot be sure that the strobili were always isosporous4 ,the genus ,schizoneura is too imperfectly known to be defined with any approach to completeness1 or to be assigned to a family defined within certain prescribed limits4 ,phyllotheca is another genus about which we possess but little satisfactory knowledge2 we are still without evidence as to its structure1 and the descriptions of the few strobili that are known are not consistent4 ,recent work points to a probability of ,phyllotheca being closely allied to ,annularia1 a genus included in the ,calamarieae1 and standing for a certain type of ,calamitean foliage-shoots4 ,in comparing the ,calamarieae with the ,equisetaceae1 the alternation of sterile and fertile whorls in the strobilus1 and the free linear leaves at the nodes instead of leaf-sheaths are two characters made use of as distinguishing features of the genus ,calamites as the type of the ,calamarieae4 ,on the other hand1 the strobili of ,phyllotheca appear to agree with those of ,calamites rather than with those of ,equisetum1 and strobili of ,archaeocalamites have been found exhibiting the typical ,equisetum characters4 ,the sheath-like form of the leaves is not necessarily peculiar to the ,equisetaceae1 and we have evidence that leaf-sheaths occurred on the nodes of ,calamitean plants4 ,in ,archaeocalamites the leaves possess characteristic features1 and can hardly be said to agree more closely with those of ,calamites than with the leaves of ,phyllotheca or ,sphenophyllum1 a genus belonging to another class of ,pteridophytes4 ,on the whole1 then1 without discussing further the possibilities of a subdivision of the ,equisetales1 we may regard the genera ,calamites1 ,archaeocalamites1 ,equisetites1 ,equisetum1 ,phyllotheca and ,schizoneura as so many members of the ,equisetales1 without insisting on a classification which cannot be supported by satisfactory evidence4 ,our knowledge of ,calamites is fairly complete4 ,abundant and well-preserved material from the ,coal-,measures of ,england1 and from ,permo-,carboniferous rocks of ,france1 ,germany and elsewhere1 has enabled palaeobotanists to investigate the anatomical characters of both the vegetative and reproductive structures of this genus4 ,we are in a position to give a detailed diagnosis of ,calamitean stems1 roots and strobili1 and to determine the place of this type of plant in a system of classification4 ,calamites not only illustrates the possibilities of palaeobotanical research1 but it demonstrates the importance of fossil forms as foundations on which to construct the most rational classification of existing plants4 ,the close alliance between ,calamites and the recent ,equisetaceae has been clearly established1 and certain characteristics of the former genus render necessary an extension and modification of the definition of the class to which both ,calamites and ,equisetites belong4 ,the ,calamites broaden our conception of the ,equisetaceous alliance1 and by their resemblance to other extinct ,palaeozoic types they furnish us with important links towards a phylogenetic series1 which the other members of the ,equisetales do not supply4 ,from the ,upper ,devonian to the ,permian epoch ,calamites and other closely related types played a prominent part in the vegetation of the world4 ,we have no good evidence for the existence of ,calamites in ,triassic times2 in its place there were gigantic ,equisetums which resembled modern ,horse-tails in a remarkable degree4 ,in the succeeding ,jurassic period tree-like ,equisetums were still in existence1 and species of ,equisetites are met with in rocks of this age in nearly all parts of the world4 ,a few widely distributed species are known from ,wealden rocks1 but as we ascend the geologic series from the ,jurassic strata1 the ,equisetums become less numerous and the individual plants gradually assume proportions practically identical with those of existing forms4 ,a4 ,equisetites4 ,the generic name ,equisetites was proposed by ,sternberg in #ahchdif as a convenient designation for fossil stems bearing a close resemblance to recent species of ,equisetum4 ,some authors have preferred to apply the name ,equisetum to fossil and recent species alike1 but in spite of the apparent identity in the external characters of the fossil stems with those of existing ,horse-tails1 and a close similarity as regards the cones1 there are certain reasons for retaining ,sternberg's generic name4 ,it is important to avoid such nomenclature as might appear to express more than the facts admit4 ,if the custom of adding the termination -ites to the root of a recent generic term is generally followed1 it at once serves to show that the plants so named are fossil and not recent species4 ,moreover1 in the case of fossil ,equisetums we know nothing of their internal structure1 and our comparisons are limited to external characters4 ,stems1 cones1 tubers1 and leaves are often very well preserved as sandstone casts with distinct surface-markings1 but we are still in want of petrified specimens4 ,there is indeed evidence that some of the ,triassic and ,jurassic species of ,equisetites1 like the older ,calamites1 possessed the power of secondary growth in thickness1 but our deductions are based solely on external characters4 ,in the following pages a few of the better known species of ,equisetites are briefly described1 the examples being chosen partly with a view to illustrate the geological history of the genus1 and partly to contribute something towards a fuller knowledge of particular species4 ,one of the most striking facts to be gleaned from a general survey of the past history of the ,equisetaceae is the persistence since the latter part of the ,palaeozoic period of that type of plant which is represented by existing ,equisetums4 ,there is perhaps no genus in existence which illustrates more vividly than ,equisetum the survival of an extremely ancient group1 which is represented to-day by numerous and widely spread species4 ,the ,equisetaceous characteristics mark an isolated division of existing ,vascular ,cryptogams1 and without reference to extinct types it is practically impossible to do more than vaguely guess at the genealogical connections of the family4 ,when we go back to ,palaeozoic plants there are indications of guiding lines which point the way to connecting branches between the older ,equisetales and other classes of ,pteridophytes4 ,the recently discovered genus ,cheirostrobus#dig is especially important from this point of view4 ,sidenote3 ,,leaf-,,sheaths ,,of ,,equisetites4 ,the accurate description of species1 and the determination of the value of such differences as are exhibited in the surface characters of structureless casts1 are practically impossible in many of the fossil forms4 ,in certain living ,horse-tails we find striking differences between fertile and sterile shoots1 and between branches of different orders4 ,the isolated occurrence of fragments of fossil stems often leads to an artificial separation of #8species' largely founded on differences in diameter1 or on slight variations in the form of the leaf-sheaths4 ,it is wiser to admit that in many cases we are without the means of accurate diagnosis1 and that the specific names applied to fossil ,equisetums do not always possess much value as criteria of taxonomic differences4 ,the specimens of fossil ,equisetums are usually readily recognised by the coherent leaf-segments in the form of nodal sheaths resembling those of recent species4 ,the tissues of the cortex and central cylinder are occasionally represented by a thin layer of coal pressed on to the surface of a sandstone cast1 or covering a flattened stem-impression on a piece of shale4 ,it is sometimes possible under the microscope to recognise on the carbonised epidermal tissues the remains of a surface-ornamentation similar to that in recent species1 which is due to the occurrence of siliceous patches on the superficial cells4 ,longitudinal rows of stomata may also be detected under favourable conditions of preservation4 ,the nodal diaphragms of stems have occasionally been preserved apart1 but such circular and radially-striated bodies may be misleading if found as isolated objects4 ,casts of the wide hollow pith of ,equisetites1 with longitudinal ridges and grooves1 and fairly deep nodal constrictions1 have often been mistaken for the medullary casts of ,calamites4 ,several species of ,equisetites have been recorded from the ,upper ,coal-,measures and overlying ,permian rocks1 but these present special difficulties4 ,in one instance described below1 7,equisetites ,hemingwayi ,kidst471 the species was founded on a cast of what appeared to be a strobilus made up of sporophylls similar to those in an ,equisetum cone4 ,in other ,permo-,carboniferous species the choice of the generic name ,equisetites has been determined by the occurrence of leaf-sheaths either isolated or attached to the node of a stem4 ,the question to consider is1 how far may the ,equisetum-like leaf-sheath be regarded as a characteristic feature of ,equisetites as distinct from ,calamites8 ,in the genus ,calamites the leaves are generally described as simple linear leaves arranged in a whorl at the nodes1 but not coherent in the form of a sheath 7fig4 #he74 ,the fusion of the segments into a continuous sheath or collar is regarded as a distinguishing characteristic of ,equisetites and ,equisetum4 ,the typical leaf-sheath of a recent ,horse-tail has already been described4 ,in some species we have fairly large and persistent free teeth on the upper margin of the leaf-sheath1 but in other ,equisetums the rim of the sheath is practically straight and has a truncated appearance1 the distal ends of the segments being separated from one another by very slight depressions1 as in a portion of the sheath of ,equisetum ramosissimum ,desf4 of fig4 #eh1 ,c4 ,in other leaf-sheaths of this species there are delicate and pointed teeth adherent to the margin of the coherent segments2 the teeth are deciduous1 and after they have fallen the sheath presents a truncated appearance4 ,this difference between the sheaths to which the teeth are still attached and those from which they have fallen is illustrated by fig4 #eh1 ,b and ,c2 it is one which should be borne in mind in the description of fossil species1 and has probably been responsible for erroneous specific diagnoses4 ,in some recent ,horse-tails the sheath is occasionally divided in one or two places by a slit reaching to the base of the coherent segments#dih2 this shows a tendency of the segments towards the free manner of occurrence which is usually considered a ,calamitean character4 ,in certain fossils referred to the genus ,annularia1 the nodes bear whorls of long and narrow leaves which are fused basally into a collar 7fig4 #eh1 ,d74 ,there are good grounds for believing that at least some ,annularias were the foliage shoots of true ,calamites4 ,again1 in some species of ,calamitina1 a sub-genus of ,calamites1 the leaves appear to have been united basally into a narrow sheath4 ,we see1 then1 that it is a mistake to attach great importance to the separate or coherent character of leaf-segments in attempting to draw a line between the true ,calamites and ,equisetites4 ,potoni#dii while pointing out that this distinction does not possess much value as a generic character1 retains the genus ,equisetites for certain ,palaeozoic ,equisetum-like leaf-sheaths4 ,illustration3 ,,fig4 #ef4 ,calamitean leaf-sheath4 ,from a specimen in the ,woodwardian ,museum4 a1 base of leaf-sheath2 7very slightly reduced74 ,fig4 #ef represents a rather faint impression of a leaf-sheath and nodal diaphragm4 ,the specimen is from the ,coal-,measures of ,ardwick1 ,manchester4 ,the letter a probably points to the attachment of the sheath to the node of the stem4 ,the flattened sheath is indistinctly divided into segments1 and at the middle of the free margin there appears to be a single free tooth4 ,the lower part of the specimen1 as seen in the figure1 shows the position of the nodal diaphragm4 ,between the diaphragm and the sheath there are several slight ridges converging towards the nodal line2 these agree with the characteristic ridges and grooves of ,calamite casts which are described in detail in ,chapter ,x4 ,there is another specimen in the ,british ,museum which illustrates1 rather more clearly than that shown in fig4 #ef1 the association of a fused leaf-sheath with a type of cast usually regarded as belonging to a ,calamitean stem4 ,some leaf-sheaths of ,permian age described by ,zeiller#ejj as ,equisetites ,vaujolyi bear a close resemblance to the sheath in fig4 #eh ,e4 ,the nature of the true ,calamite leaves is considered more fully on a later page4 ,sidenote3 ,,palaeozoic ,,equisetites4 ,the examples of supposed ,equisetites sheaths referred to below may serve to illustrate the kind of evidence on which this genus has been recorded from ,upper ,palaeozoic rocks4 ,i have retained the name ,equisetites in the description of the species1 but it would probably be better to speak of such specimens as #8,calamitean leaf-sheaths' rather than to describe them as definite species of ,equisetites4 ,we have not as yet any thoroughly satisfactory evidence that the ,equisetites of ,triassic and post-,triassic times existed in the vegetation of earlier periods4 ,in ,grand',eury's ,flore du ,gard#eja a fossil strobilus is figured under the name ,calamostachys tenuissima ,grand',eury1 which consists of a slender axis bearing series of sporophylls and sporangia apparently resembling those of an ,equisetum4 ,there are no sterile appendages or bracts alternating with the sporophylls2 and the absence of the former suggests a comparison with ,equisetites rather than ,calamites4 ,grand',eury refers to the fossil as 8parfois peine perceptible10 and a recent examination of the specimen leads me to thoroughly endorse this description4 ,it was impossible to recognise the features represented in ,grand',eury's drawing4 ,setting aside this fossil1 there are other strobili recorded by ,renault#ejb and referred by him to the genus ,bornia 7,archaeocalamites71 which also exhibit the ,equisetum-like character2 the axis bears sporophylls only and no sterile bracts4 ,it would appear then that in the ,palaeozoic period the ,equisetaceous strobilus1 as we know it in ,equisetum1 was represented in some of the members of the ,equisetales4 ,illustration3 ,,fig4 #eg4 ,a4 ,equisetites ,hemingwayi ,kidst4 ,from a specimen in the ,british ,museum4 nat4 size4 ,b4 ,diaphragm and sheath of an ,equisetaceous plant1 from the ,coal-,measures4 nat4 size4 ,from a specimen in the ,british ,museum4 #a4 ,equisetites ,hemingwayi ,kidst4 ,fig4 #eg1 ,a4 ,mr ,kidston#ejc founded this species on a few specimens of cones found in the ,middle ,coal-,measures of ,barnsley in ,yorkshire4 ,the best example of the cone described by ,kidston has a length of #be cm41 and a breadth of #ae cm42 the surface is divided up into several hexagonal areas #d mm4 high and #e mm4 wide4 ,each of these plates shows a fairly prominent projecting point in its centre2 this is regarded as the point of attachment of the sporangiophore axis which expanded distally into a hexagonal plate bearing sporangia4 ,an examination of ,mr ,kidston's specimens enabled me to recognise the close resemblance which he insists on between the fossils and such a recent ,equisetaceous strobilus as that of ,equisetum limosum ,sm4 ,nothing is known of the structure of the fossils beyond the character of the superficial pattern of the impressions1 and it is impossible to speak with absolute confidence as to their nature4 ,the author of the species makes use of the generic name ,equisetum2 but in view of our ignorance of structural features it is better to adopt the more usual term ,equisetites4 ,since ,kidston's description was published ,i noticed a specimen in the ,british ,museum collection which throws some further light on this doubtful fossil4 ,part of this specimen is shown in fig4 #eg1 ,a4 ,the stem is #ba cm4 in length and about #e mm4 broad2 it is divided into distinct nodes and internodes2 the former being a little exaggerated in the drawing4 ,the surface is marked by fine and irregular striations1 and in one or two places there occur broken pieces of narrow linear leaves in the neighbourhood of a node4 ,portions of four cones occurring in contact with the stem1 appear to be sessile on the nodes1 but the preservation is not sufficiently good to enable one to speak with certainty as to the manner of attachment4 ,each cone consists of regular hexagonal depressions1 which agree exactly with the surface characters of ,kidston's type-specimen4 ,the manner of occurrence of the cones points to a lateral and not a terminal attachment4 ,the stem does not show any traces of ,equisetaceous leaf-sheaths at the nodes1 and such fragments of leaves as occur appear to have the form of separate linear segments2 they are not such as are met with on ,equisetites4 ,it agrees with some of the slender foliage-shoots of ,calamitean plants often described under the generic name ,asterophyllites4 ,as regards the cones2 they differ from the known ,calamitean strobili in the absence of sterile bracts1 and appear to consist entirely of distally expanded sporophylls as in ,equisetum4 ,the general impression afforded by the fossil is that we have not sufficient evidence for definitely associating this stem and cones with a true ,equisetites4 ,we may1 however1 adhere to this generic title until more satisfactory data are available4 #b4 ,equisetites spatulatus ,zeill4 ,fig4 #eh1 ,a4 ,this species is chosen as an example of a ,french ,equisetites of ,permian age4 ,it was recently founded by ,zeiller#ejd on some specimens of imperfect leaf-sheaths1 and defined as follows3-- ,sheaths spreading1 erect1 formed of numerous uninerved coherent leaves1 convex on the dorsal surface1 spatulate in form1 #e-f cm4 in length and #b-c mm4 broad at the base1 and #e-aj mm4 broad at the apex1 rounded at the distal end4 ,the specimen shown in fig4 #eh1 ,a1 represents part of a flattened sheath1 the narrower crenulated end being the base of the sheath4 ,the limits of the coherent segments and the position of the veins are clearly marked4 ,zeiller's description accurately represents the character of the sheaths4 ,they agree closely with an ,equisetaceous leaf-sheath1 but as ,i have already pointed out1 we cannot feel certain that sheaths of this kind were not originally attached to a ,calamite stem4 ,the portion of a leaf-sheath and a diaphragm represented in fig4 #eg1 ,b1 agrees closely with ,zeiller's examples4 ,this specimen is from the ,english ,coal-,measures1 but it is not advisable to attempt any specific diagnosis on such fragmentary material4 ,it is questionable1 indeed1 if these detached fossil leaf-sheaths should be designated by specific names4 ,another similar form of sheath1 hardly distinguishable from ,zeiller's species1 has recently been described by ,potoni from the ,permian 7,rothliegende7 of ,thuringia4 ,illustration3 ,,fig4 #eh4 ,a4 ,equisetites spatulatus1 ,zeill4 ,leaf-sheath4 nat4 size4 7,after ,zeiller47 ,b4 ,e4 columnaris1 ,brongn4 ,from a specimen in the ,british ,museum4 nat4 size4 ,c4 ,equisetum ramosissimum1 ,desf4 #b4 ,d4 ,annularia stellata 7,schloth474 ,leaf-sheath4 ,slightly enlarged4 7,after ,potoni47 ,e4 ,equisetites zeaeformis 7,schloth474 ,leaf-sheath4 nat4 size4 7,after ,potoni47 ,f4 ,e4 lateralis1 ,phill4 ,from a specimen in the ,scarborough ,museum4 ,nat4 size4 #c4 ,equisetites zeaeformis 7,schloth47#eje ,fig4 #eh1 ,e4 ,the sheaths consist of linear segments fused laterally as in ,equisetum4 ,in some specimens the component parts of the sheath are more or less separate from one another1 and in this form they are apparently identical with the leaves of ,calamites 7,calamitina7 varians1 ,sternb4 ,the example shown in fig4 #eh1 ,e is probably a young leaf-sheath2 the segments are fused1 and each is traversed by a single vein represented by a dark line in the figure4 ,the regular crenulated lower margin is the base of the sheath1 and corresponds to the upper portion of fig4 #eh1 ,a4 ,this species affords1 therefore1 an interesting illustration of the difficulty of separating ,equisetites leaves from those of true ,calamites4 ,potoni has suggested that the leaf-sheath of a young ,calamite might well be split up into distinct linear segments as the result of the increase in girth of the stem4 ,other ,palaeozoic species of ,equisetites have been recorded1 but with one exception these need not be dealt with1 as they do not add anything to our knowledge of botanical importance4 ,the specimen described in the ,flore de ,commentry as ,equisetites ,monyi1 by ,renault and ,zeiller#ejf1 differs from most of the other ,palaeozoic species of ,equisetites1 in the fact that we have a stem with short internodes bearing a leaf-sheath at each node divided into comparatively long and distinct teeth4 ,this species presents a close agreement with specimens of ,calamitina1 but ,renault and ,zeiller consider that it is generically distinct4 ,they suggest that the ,english species1 originally described and figured by ,lindley and ,hutton#ejg as ,hippurites gigantea1 and now usually spoken of as ,calamitina1 should be named ,equisetites4 ,it would probably be better to adopt the name ,calamitina for the ,french species4 ,the type-specimen of this species is in the ,natural ,history ,museum1 ,paris4 ,sidenote3 ,,equisetites ,,platyodon4 ,illustration3 ,,fig4 #ei4 ,equisetites platyodon ,brongn4 7,after ,schoenlein1 slightly reduced47 ,when we pass from the ,permian to the ,triassic period1 we find large casts of very modern-looking ,equisetaceous stems which must clearly be referred to the genus ,equisetites4 ,the portion of a stem represented in fig4 #ei known as ,equisetites platyodon ,brongn4#ejh affords an example of a ,triassic ,equisetaceous stem with a clearly preserved leaf-sheath4 ,the stem measures about #f cm4 in diameter4 ,one of the oldest known ,triassic species is ,equisetites ,mougeoti#eji 7,brongn47 from the ,bunter series of the ,vosges4 ,the ,keuper species ,e4 arenaceus is1 however1 more completely known4 ,the specimens referred to this species are very striking fossils2 they agree in all external characters with recent ,horse-tails but greatly exceed them in dimensions4 #d4 ,equisetites arenaceus ,bronn4 ,this plant has been found in the ,triassic rocks of various parts of ,germany and ,france2 it occurs in the ,lettenkohl group 7,lower ,keuper71 as well as in the ,middle ,keuper of ,stuttgart and elsewhere4 ,the species may be defined as follows3-- ,rhizome from #h-ad cm4 in diameter1 with short internodes1 bearing lateral ovate tubers4 ,aerial shoots from #d-ab cm4 in diameter1 bearing whorls of branches1 and leaf-sheaths made up of #aaj-abj coherent uni-nerved linear segments terminating in an apical lanceolate tooth4 ,strobili oval1 consisting of crowded sporangiophores with pentagonal and hexagonal peltate terminations4 ,the casts of branches1 rhizomes1 tubers1 buds and cones enable us to form a fairly exact estimate of the size and general appearance of this largest fossil ,horse-tail4 ,the ,strassburg ,museum contains many good examples of this species1 and a few specimens may be seen in the ,british ,museum4 ,in the cole des ,mines1 ,paris1 there are some exceptionally clear impressions of cones of this species from a lignite mine in the ,vosges4 ,it is estimated that the plant reached a height of #h to #aj meters1 about equal to that of the tallest recent species of ,equisetum1 but in the diameter of the stems the ,triassic plant far exceeded any existing species4 ,it is interesting to determine as far as possible1 in the absence of petrified specimens1 if this ,keuper species increased in girth by means of a cambium4 ,there are occasionally found sandstone casts of the pith-cavity which present an appearance very similar to that of ,calamitean medullary casts#eaj4 ,the nodes are marked by comparatively deep constrictions1 which probably represent the projecting nodal wood4 ,the surface of the casts is traversed by regular ridges and grooves as in an ordinary ,calamite1 and it is probable that in ,equisetites arenaceus1 as in ,calamites1 these surface-features are the impression of the inner face of a cylinder of secondary wood 7cf4 p4 #caj74 ,excellent figures of this species of ,equisetites are given by ,schimper in his ,atlas of fossil plants#eaa1 also by ,schimper and ,koechlin-,schlumberger#eab1 and by ,schoenlein and ,schenk#eac4 #e4 ,equisetites columnaris ,brongn4 ,figs4 #aa and #eh1 ,b4 ,this species1 which is by far the best known ,british ,equisetites1 was founded by ,brongniart#ead on some specimens from the ,lower ,oolite beds of the ,yorkshire coast4 ,casts of stems are familiar to those who have collected fossils on the coast between ,whitby and ,scarborough2 they are often found in an erect position in the sandstone1 and are usually described as occurring in the actual place of growth4 ,as previously pointed out 7p4 #gb71 such stems have generally been deposited by water1 and have assumed a vertical position 7fig4 #aa74 ,young and ,bird#eae figured a specimen of this species in #ahbb1 and in view of its striking resemblance to the sugar-cane1 they regarded the fossil as being of the same family as ,saccharum officinarum1 if not specifically identical4 ,a specimen was described by ,knig#eaf in #ahbi1 from the ,lower ,oolite rocks of ,brora in the north of ,scotland under the name of ,oncylogonatum carbonarium1 but ,brongniart#eag pointed out its identity with the ,english species ,equisetites columnaris4 ,our acquaintance with this species is practically limited to the casts of stems4 ,a typical stem of ,e4 columnaris measures #c to #f cm4 in diameter and has fairly long internodes4 ,the largest stem in the ,british ,museum collection has internodes about #ad cm4 long and a diameter of about #e cm4 ,in some cases the stem casts show irregular lateral projections in the neighbourhood of a node1 but there is no evidence that the aerial shoots of this species gave off verticils of branches4 ,in habit ,e4 columnaris probably closely resembled such recent species as ,equisetum hiemale ,l41 ,e4 trachyodon ,a4 ,br4 and others4 ,the stems often show a distinct swelling at the nodes2 this may be due1 at least in part1 to the existence of transverse nodal diaphragms which enabled the dead shoots to resist contraction in the region of the nodes4 ,the leaf-sheaths consist of numerous long and narrow segments often truncated distally1 as in fig4 #eh1 ,b1 and as in the sheath of such a recent ,horse-tail as ,e4 ramosissimum shown in fig4 #eh1 ,c4 ,in some specimens one occasionally finds indications of delicate acuminate teeth extending above the limits of a truncated sheath4 ,brongniart speaks of the existence of caducous acuminate teeth in his diagnosis of the species1 and the example represented in fig4 #eh1 ,b1 demonstrates the existence of such deciduous appendages4 ,there is a very close resemblance between the fossil sheath of fig4 #eh1 ,b1 with and without the teeth1 and the leaf-sheath of the recent ,equisetum in fig4 #eh1 ,c4 ,in some specimens of ,e4 columnaris in which the cast is covered with a carbonaceous film1 each segment in a leaf-sheath is seen to be slightly depressed in the median portion1 which is often distinctly marked by numerous small dots1 the edges of the segment being flat and smooth4 ,the median region is that in which the stomata are found and on which deposits of silica occur4 #f4 ,equisetites ,beani 7,bunb474 ,figs4 #fj-fb4 ,bunbury#eah proposed the name ,calamites ,beani for some fossil stems from the ,lower ,oolite beds of the ,yorkshire coast1 which ,bean had previously referred to in unpublished notes as ,c4 giganteus4 ,the latter name was not adopted by ,bunbury on account of the possible confusion between this species and the ,palaeozoic species ,calamites gigas ,brongn4 ,the generic name ,calamites must be replaced by ,equisetites now that we are familiar with more perfect specimens which demonstrate the ,equisetean characters of the plant4 ,illustration3 ,,fig4 #fj4 ,equisetites ,beani 7,bunb474 nat4 size4 ,after ,starkie ,gardner 7#hf7 ,pl4 ,,ix4 fig4 #b4 ,schimper#eai speaks of this species as possibly the pith-cast of ,equisetites columnaris1 but his opinion cannot be maintained2 the species first described by ,bunbury has considerably larger stems than those of ,e4 columnaris4 ,it is not impossible1 however1 that ,e4 columnaris and ,e4 ,beani may be portions of the same species4 ,the chief difference between these forms is that of size2 but we have not sufficient data to justify the inclusion of both forms under one name4 ,zigno#ebj1 in his work on the ,oolitic ,flora1 figures an imperfect stem cast of ,e4 ,beani under the name of ,calamites ,beani1 but the species has received little attention at the hands of recent writers4 ,in #ahhf ,starkie ,gardner#eba figured a specimen which was identified by ,williamson as an example of ,bunbury's species2 but the latter pointed out the greater resemblance1 as regards the external appearance of the ,jurassic stem1 to some of the recent arborescent ,gramineae#ebb than to the ,equisetaceae4 ,williamson1 with his usual caution1 adds that such appearances have very little taxonomic value4 ,fig4 #fj is reproduced from the block used by ,gardner in his memoir on ,mesozoic ,angiosperms2 he quotes the specimen as possibly a ,monocotyledonous stem4 ,the fossil is an imperfect cast of a stem showing two clearly marked nodal regions1 but no trace of leaf-sheaths4 ,a recent examination of specimens in the museums of ,whitby1 ,scarborough1 ,york and ,london has convinced me that the plant named by ,bunbury ,calamites ,beani is a large ,equisetites4 ,as a rule the specimens do not show any indications of the leaf-sheaths1 but in a few cases the sheaths have left fairly distinct impressions4 ,illustration3 ,,fig4 #fa4 ,equisetites ,beani 7,bunb474 ,from a specimen in the ,british ,museum1 nat4 size4 7,no4 ,v4 #bgbe47 ,in the portion of stem shown in fig4 #fa the impressions of the leaf segments are clearly marked4 ,this specimen affords much better evidence of the ,equisetaceous character of the plant than those which are simply internal casts4 ,the narrow projecting lines extending upwards from the nodes in the figured specimen probably represent the divisions between the several segments of each leaf-sheath4 ,in the museums of ,whitby and ,scarborough there are some long specimens1 in one case #dd cm4 in length1 and #cc cm4 in circumference1 which are probably casts of the broad pith-cavity4 ,these casts are often transversely broken across at the nodes1 so that they consist of three or four separate pieces which fit together by clean-cut faces4 ,this manner of occurrence is most probably due to the existence of large and resistant nodal diaphragms which separated the sand-casts of adjacent internodes4 ,in the ,york museum there are some large diaphragms1 #aj cm4 in diameter1 preserved separately in a piece of rock containing a cast of ,equisetites ,beani4 ,the nodal diaphragms of some of the ,carboniferous ,calamites were the seat of cork development#ebc1 and it may be that the frequent preservation of ,equisetaceous diaphragms in ,triassic and ,jurassic rocks is due to the protection afforded by a corky investment4 ,the stem shown in fig4 #fb appears to be a portion of a shoot of ,e4 ,beani not far from its apical region4 ,from the lower nodes there extend clearly marked and regular lines or slight grooves tapering gradually towards the next higher node2 these are no doubt the impressions of segments of leaf-sheaths4 ,the sheaths themselves have been detached and only their impressions remain4 ,the flattened bands at the node of the stem in fig4 #fj1 and shown also in fig4 #fa1 mark the place of attachment of the leaf-sheaths4 ,on some of these nodal bands one is able to recognise small scars which are most likely the casts of outgoing leaf-trace bundles4 ,some of the internal casts of this species are marked by numerous closely arranged longitudinal lines1 which are probably the impressions of the inner face of a central woody cylinder4 ,in the smaller specimen shown in fig4 #fb we have the apical portion of a shoot in which the uppermost internodes are in an unexpanded condition4 ,illustration3 ,,fig4 #fb4 ,equisetites ,beani 7,bunb474 ,from a specimen in the ,scarborough ,museum4 ,very slightly reduced4 ,it is impossible to give a satisfactory diagnosis of this species without better material4 ,the plant is characterised chiefly by the great breadth of the stem1 and by the possession of leaf-sheaths consisting of numerous long and narrow segments4 ,equisetites ,beani must have almost equalled in size the ,triassic species1 ,e4 arenaceus1 described above4 #g4 ,equisetites lateralis ,phill4 ,figs4 #eh1 ,f1 #fc1 and #fd4 ,this species is described at some length as affording a useful illustration of the misleading character of certain features which are entirely due to methods of preservation4 ,the specific name was proposed by ,phillips in his first edition of the ,geology of the ,yorkshire ,coast for some very imperfect stems from the ,lower ,oolite rocks near ,whitby#ebd4 ,the choice of the term lateralis illustrates a misconception2 it was given to the plant in the belief that certain characteristic wheel-like marks on the stems were the scars of branches4 ,lindley and ,hutton#ebe figured a specimen of this species in their ,fossil ,flora1 and quoted a remark by 8,mr ,williamson junior0 7afterwards ,prof4 ,williamson7 that the so-called scars often occur as isolated discs in the neighbourhood of the stems4 ,bunbury#ebf described an example of the same species with narrow spreading leaves like those of a ,palaeozoic ,asterophyllites1 and proposed this generic name as more appropriate than ,equisetites4 ,in all probability the example shown in fig4 #fc is that which ,bunbury described4 ,it is certainly the same as one figured by ,zigno#ebg as ,calamites lateralis in his ,flora fossilis formationis ,oolithicae4 ,illustration3 ,,fig4 #fc4 ,equisetites lateralis ,phill4 ,from a specimen in the ,british ,museum4 ,slightly reduced4 ,this specimen illustrates a further misconception in the diagnosis of the species4 ,the long linear appendages spreading from the nodes are1 ,i believe1 slender branches and not leaves2 they have not the form of delicate filmy markings on the rock face1 but are comparatively thick and almost woody in appearance4 ,the true leaves are distinctly indicated at the nodes1 and exhibit the ordinary features of toothed sheaths4 ,heer#ebh proposed to transfer ,phillips' species to the genus ,phyllotheca1 and ,schimper#ebi preferred the generic term ,schizoneura4 ,the suggestion for the use of these two names would probably not have been made had the presence of the ,equisetum sheaths been recognised4 ,the circular depressions a short distance above each node are the #8branch scars' of various writers4 ,schimper suggested that these radially marked circles might be displaced nodal diaphragms4 ,andrae#ecj figured the same objects in #ahec but regarded them as branch scars1 although in the specimen he describes1 there are several of them lying apart from the stems1 and to one of them is attached a portion of a leaf-sheath4 ,solms-,laubach#eca points out that the internodal position of these supposed scars is an obvious difficulty2 we should not expect to find branches arising from an internode4 ,after referring to some specimens in the ,oxford museum1 he adds--8,in presence of these facts the usual explanation of these structures appears to me1 as to ,heer1 very doubtful4444 ,we are driven to the very arbitrary assumption that they represent the lowest nodes of the lateral branches which were inserted above the line of the nodes of the stem40 ,circular discs similar to those of ,e4 lateralis have been found in the ,jurassic rocks of ,siberia#ecb and elsewhere4 ,there are one or two examples of such discs from ,siberia in the ,british ,museum4 ,if the nodal diaphragms were fairly hard and stout1 it is easy to conceive that they might have been pressed out of their original position when the stems were flattened in the process of fossilisation4 ,it is not quite clear what the radial spoke-like lines of the discs are due to2 possibly they mark the position of bands of more resistant tissue or of outgoing strands of vascular bundles4 ,a detached diaphragm is seen in fig4 #fd ,c2 in the centre it consists of a flat plate of tissue1 and the peripheral region is traversed by the radiating lines4 ,in the stem of fig4 #fd1 ,a the deeply divided leaf-sheaths are clearly seen1 and an imperfect impression of a diaphragm is preserved on the face of the middle internode4 ,in fig4 #fd ,b a flattened leaf-sheath is shown with the free acuminate teeth fused basally into a continuous collar#ecc4 ,the short piece of stem of ,equisetites lateralis shown in fig4 #eh1 ,f1 shows how the free teeth may be outspread in a manner which bears some resemblance to the leaves of ,phyllotheca1 but a comparison with the specimens already described1 and a careful examination of this specimen itself1 demonstrate the generic identity of the species with ,equisetites4 ,the carbonaceous film on the surface of such stems as those of fig4 #eh1 ,f1 and #fd1 ,a1 shows a characteristic shagreen texture which may possibly be due to the presence of silica in the epidermis as in recent ,horse-tails4 ,there is another species of ,equisetites1 ,e4 ,mnsteri1 ,schk41 from a lower geological horizon which has been compared with ,e4 lateralis1 and lends support to the view that the so-called branch-scars are nodal diaphragms#ecd4 ,this species also affords additional evidence in favour of retaining the generic name ,equisetites for ,phillips' species4 ,equisetites ,mnsteri is a typical ,rhaetic plant2 it has been found at ,beyreuth and ,kuhnbach1 as well as in ,switzerland1 ,hungary and elsewhere4 ,a specimen of ,equisetites originally described by ,buckman as ,e4 ,brodii#ece1 from the ,lower ,lias of ,worcestershire1 may possibly be identical with ,e4 ,mnsteri4 ,the leaf-sheaths of this ,rhaetic species consist of broad segments prolonged into acuminate teeth2 some of the examples figured by ,schenk#ecf show clearly marked impressions of displaced nodal diaphragms exactly as in ,e4 lateralis4 ,another form1 ,equisetum rotiferum described by ,tenison-,woods#ecg from ,australia1 is closely allied to1 or possibly identical with ,e4 lateralis4 ,illustration3 ,,fig4 #fd4 ,equisetites lateralis ,phill4 ,a4 ,part of a stem showing leaf-sheaths and an imperfect diaphragm4 ,b4 ,a single flattened leaf-sheath4 ,c4 ,a detached nodal diaphragm4 ,from a specimen in the ,york ,museum4 ,slightly reduced4 #h4 ,equisetites ,burchardti ,dunker#ech4 ,fig4 #fe4 ,this species of ,equisetites is fairly common in the ,wealden beds of the ,sussex coast near ,hastings1 and also in ,westphalia4 ,illustration3 ,,fig4 #fe4 ,equisetites ,burchardti ,dunk4 ,showing a node with two tubers and a root4 ,from a specimen in the ,british ,museum4 ,nat4 size4 ,it is characterised by having long and slender internodes1 bearing at the nodes leaf-sheaths with five or six pointed segments1 and by the frequent formation of branch-tubers4 ,these tuberous branches closely resemble those which are formed on the underground shoots of ,equisetum arvense ,l41 ,e4 sylvaticum ,l4 and others2 they occur either singly or in chains#eci4 ,in the specimen shown in the figure the left-hand tuber is remarkably well preserved1 its surface is somewhat sunk and shrivelled1 and the apex is surrounded by a nodal leaf-sheath4 ,a thin branched root is given off just below the point of insertion of the oval tuber4 ,no other species of ,equisetites affords such numerous examples of tubers as this ,wealden plant4 ,by some of the earlier writers the detached tubers of ,e4 ,burchardti were described as fossil seeds under the name ,carpolithus4 ,illustration3 ,,fig4 #ff4 ,equisetites ,yokoyamae ,sew4 ,from specimens in the ,british ,museum4 ,nat4 size4 ,the specimens shown in fig4 #ff have been referred to another species1 ,e4 ,yokoyamae ,sew4#edj2 they were obtained from the ,wealden beds of ,sussex1 but according to ,mr ,rufford1 who discovered them1 the smaller tubers of this species are not found in association with those of ,e4 ,burchardti4 ,the stems are very narrow and the tubers have a characteristic elliptical form2 the species is of little value botanically1 but it affords another instance of the common occurrence of these tuberous branches in the ,wealden ,equisetums4 ,similar fossil tubers1 on a much larger scale1 have been found in association with the ,triassic ,equisetites arenaceus2 with ,e4 ,parlatori ,heer#eda1 a ,tertiary species from ,switzerland1 and with other ,mesozoic and ,tertiary stems4 ,e4 ,burejensis#edb1 described by ,heer from the ,jurassic rocks of ,siberia1 bears a close resemblance to the ,wealden species4 ,the description of the above species by no means exhausts the material which is available towards a history of fossil ,equisetums4 ,the examples which have been selected may serve to illustrate the kind of specimens that are usually met with1 as well as some of the possible sources of error which have to be borne in mind in the description of species4 ,such ,tertiary species as have been recorded need not be considered2 they furnish us with no facts of particular interest from a morphological point of view4 ,the wide distribution of ,equisetites1 especially during the ,jurassic period1 is one of the most interesting lessons to be learnt from a review of the fossil forms4 ,no doubt a detailed comparison of the several species from different parts of the world would lead us to reduce the number of specific names2 and at the same time it would emphasize the apparent identity of fossils which have been described from widely separated latitudes under different names4 ,specimens of ,equisetites are occasionally found in plant-bearing beds apart from the other members of a ,flora2 this isolated manner of occurrence suggests that the plant grew in a different station from that occupied by ,cycads and other elements of the vegetation#edc4 ,a selection of ,triassic and ,jurassic species arranged in a tabular form demonstrates the world-wide distribution of this persistent type of plant#edd4 ,b4 ,phyllotheca4 ,the generic name ,phyllotheca was proposed by ,brongniart#ede in #ahbh for some small fossil stems from the ,hawkesbury river1 near ,port ,jackson1 ,australia4 ,the stems of this genus are divided into nodes and internodes and possess leaf-sheaths as in ,equisetum1 but ,phyllotheca differs from other ,equisetaceous plants in the form of the leaves and in the character of its sporophylls4 ,we may define the genus as follows3-- ,plants resembling in habit the recent ,equisetums4 ,stems simple or branched1 divided into distinct nodes and internodes1 the latter marked by longitudinal ridges and grooves2 from the nodes are given off leaf-sheaths consisting of linear-lanceolate uninerved segments coherent basally1 but having the form of free narrow teeth for the greater part of their length4 ,the long free teeth are usually spread out in the form of a cup and not adpressed to the stem1 the tips of the teeth are often incurved4 ,the sporangia are borne on peltate sporangiophores attached to the stem between whorls of sterile leaves4 ,our knowledge of ,phyllotheca is unfortunately far from complete4 ,the chief characteristic of the vegetative shoots consists in the cup-like leaf-sheaths2 these are divided up into several linear segments1 which differ from the teeth of an ,equisetum leaf-sheath in their greater length and in their more open and spreading habit of growth4 ,the large loose sheaths of the fertile shoots of some recent ,horse-tails bear a certain resemblance to the sheaths of ,phyllotheca4 ,the diagnosis of the fertile shoots is founded principally on some ,permian specimens of the genus described by ,schmalhausen from ,russia#edf and redescribed more recently by ,solms-,laubach#edg4 ,prof4 ,zeiller#edh has1 however1 lately received some examples of ,phyllotheca from the ,coal-,measures of ,asia ,minor which bear strobili like those of the genus ,annularia1 a type which is dealt with in the succeeding chapter4 ,a description of a few species will serve to illustrate the features usually associated with this generic type1 as well as to emphasize the unsatisfactory state of our knowledge as to the real significance of such supposed generic characteristics4 ,there are a few fossil stems from ,permian rocks of ,siberia1 from ,jurassic strata in ,italy1 and from ,lower ,mesozoic and ,permo-,carboniferous beds in ,south ,america1 ,south ,africa1 ,india and ,australia which do not conform in all points to the usually accepted definition of ,equisetites1 and so justify their inclusion in an allied genus4 ,on the other hand there are numerous instances of stems or branches which have been referred to ,phyllotheca on insufficient grounds4 ,our knowledge of this ,equisetaceous plant has recently been extended by ,zeiller#edi1 who has recorded its occurrence in the ,coal-,measures of ,asia ,minor associated with typical ,upper ,carboniferous plants4 ,the same author#eej has also brought forward good evidence for the ,permian age of the beds in ,siberia and ,altai1 where ,phyllotheca has long been known4 ,it is true that ,zigno's species of the genus occurs in ,italian ,jurassic rocks1 but on the whole it would seem that this genus is rather a ,permian than a ,jurassic type4 ,the species which ,zeiller describes under the name ,phyllotheca ,rallii from the ,coal-,measures of ,herakleion 7,asia ,minor7 shows some points of contact with ,annularia4 ,it is much to be desired1 however1 that we might learn more as to the reproductive organs of this member of the ,equisetales2 until we possess a closer acquaintance with the fructification we cannot hope to arrive at any satisfactory conclusion as to the exact position of the genus among the ,calamarian and ,equisetaceous forms4 ,m4 ,zeiller#eea informs me that his specimens of ,p4 ,rallii1 which are to be fully described in a forthcoming work1 include fossil strobili resembling those of ,annularia radiata4 ,the verticils of linear leaves fused basally into a sheath agree in appearance with the star-like leaves of ,annularia1 but in ,phyllotheca ,rallii the segments appear to spread in all directions and are not extended in one plane as in the typical ,annularia#eeb4 #a4 ,phyllotheca deliquescens 7,gpp474 ,in an account of some fossil plants collected by ,tchikatcheff in ,altai1 ,gppert#eec describes and figures two imperfect stems of an ,equisetum-like plant4 ,owing to the apparent absence of nodal lines on the surface of the stem the generic name ,anarthrocanna is proposed for the fossils2 and the manner in which the main axis appears to break up into slender branches suggested the specific name deliquescens4 ,schmalhausen#eed afterwards recognised the generic identity of ,gppert's fragments with the ,indian and ,australian stems referred to the genus ,phyllotheca by ,mc,coy#eee and ,bunbury#eef4 ,we may define the species as follows3-- ,stem reaching a diameter of #b-c cm4 with internodes as much as #d cm4 long1 the surface of which is traversed by longitudinal ridges and grooves which are continuous and not alternate at the nodes4 ,branches arise in verticils from the nodes4 ,the leaves have the form of funnel-shaped sheaths split up into narrow and spreading linear segments1 each of which is traversed by a median vein4 ,the fertile shoot terminates in a loose strobilus bearing alternating whorls of sterile bracts and sporangiophores4 ,the specimens on which this diagnosis is founded are for the most part fragments of sterile branches4 ,some of these present the appearance of ,calamitean stems in which the ridges and grooves continue in straight lines from one internode to the next4 ,similar stem-casts have been referred by some writers to the allied genus ,schizoneura1 and it would appear to be a hopeless task to decide with certainty under which generic designation such specimens should be described4 ,the portion of stem shown in fig4 #fg affords an example of an ,equisetaceous plant1 probably in the form of a cast of a hollow pith1 which might be referred to either ,phyllotheca or ,schizoneura4 ,the specimen was found in certain ,south ,african rocks which are probably of ,permo-,carboniferous age#eeg4 ,it agrees closely with some stems from ,india described by ,feistmantel#eeh as ,schizoneura gondwanensis1 and it also resembles equally closely the ,australian specimens referred by ,feistmantel#eei to ,phyllotheca australis and some stems of ,phyllotheca indica figured by ,bunbury#efj4 ,the longitudinal ridges and grooves shown in fig4 #fg probably represent the broad medullary rays and the projecting wedges of secondary wood surrounding a large hollow pith1 as in ,calamites4 ,in the ,calamitean casts the ridges and grooves of each internode usually alternate in position with those of the next1 as in ,equisetum 7fig4 #ed1 ,a71 but in ,phyllotheca1 ,schizoneura and ,archaeocalamites there is no such regular alternation at the nodes of the internodal vascular strands4 ,illustration3 ,,fig4 #fg4 ,phyllotheca8 nat4 size4 ,from a ,south ,african specimen of ,permo-,carboniferous age in the ,british ,museum4 ,in ,phyllotheca and ,schizoneura there are no casts of #8infranodal canals' below each nodal line1 but these are by no means always found in true ,calamites4 ,it is therefore practically impossible to determine the generic position of such fossils as that shown in fig4 #fg without further evidence than is afforded by leafless casts4 ,a few examples of ,phyllotheca deliquescens have been described by ,schmalhausen in which a branch bears clusters of sporangiophores1 alternating with verticils of sterile bracts4 ,the sporangiophores appear to have the form of stalked peltate appendages bearing sporangia1 very similar to the sporangiophores of ,equisetum4 ,solms-,laubach#efa has examined the best of ,schmalhausen's specimens1 and a carefully drawn figure of one of the fertile branches is given in his ,fossil ,botany4 ,the significance of this manner of occurrence of sporangiophores and whorls of sterile bracts on the fertile branch will be better understood after a description of the strobilus of ,calamites4 ,in ,phyllotheca the sporangiophores appear to have been given off in whorls1 which were separated from one another by whorls of sterile bracts1 whereas in ,equisetum there are no sterile appendages associated with the sporangiophores of the strobilus1 with the exception of the annulus at the base of the cone4 ,heer#efb first drew attention to the fact that in ,phyllotheca we have a form of strobilus or fertile shoot to a certain extent intermediate in character between ,equisetum and ,calamites4 ,in abnormal fertile shoots of ,equisetum1 sporophylls occasionally occur above and below a sterile leaf-sheath4 ,potoni#efc has figured such an example in which an apical strobilus is succeeded at a lower level by a sterile leaf-sheath1 and this again by a second cluster of sporophylls4 ,as ,potoni points out1 this alternation of fertile and sterile members affords an interesting resemblance between ,phyllotheca and ,equisetum4 ,it suggests a partial reversion towards the ,calamitean type of strobilus4 #b4 ,phyllotheca ,brongniarti ,zigno4 ,fig4 #fh1 ,a4 ,this species of ,phyllotheca from the ,lower ,oolite rocks of ,italy is known only in the form of sterile branches4 ,the leaves are fused basally into an open cup-like sheath which is dissected into several spreading and incurved linear segments4 ,the internodes are striated longitudinally2 they are about #b mm4 in diameter and #aj mm4 in length4 ,the specimen represented in fig4 #fh1 ,a1 was originally described by the ,italian palaeobotanist ,zigno#efd2 it serves to illustrate the points of difference between this genus and the ordinary ,equisetum4 ,the open and spreading sheaths clasping the nodes and the erect solitary branches give the plant a distinctive appearance4 ,illustration3 ,,fig4 #fh4 ,a4 ,phyllotheca ,brongniarti1 ,zigno4 ,nat4 size4 7,after ,zigno47 ,b4 ,calamocladus frondosus1 ,grand',eury4 7,after ,grand',eury47 ,slightly enlarged4 ,c4 ,phyllotheca indica1 ,bunb4 ,part of a leaf-sheath4 ,from a specimen in the ,museum of the ,geological ,society4 ,slightly enlarged4 #c4 ,phyllotheca indica ,bunb4 and ,p4 australis ,brongn4 ,fig4 #fh1 ,c4 ,sir ,charles ,bunbury#efe described several imperfect specimens from the ,nagpur district of ,india under this name1 but he expressed the opinion that it was not clear to him if the plant was specifically distinct from the ,phyllotheca australis ,brongn4 previously recorded from ,new ,south ,wales4 ,feistmantel#eff subsequently described a few other ,indian specimens1 but did not materially add to our knowledge of the genus4 ,bunbury's specimens were obtained from ,bharatwd in ,nagpur1 in beds belonging to the ,damuda series of the ,lower ,gondwana rocks1 usually regarded as of about the same age as the ,permian rocks of ,europe4 ,phyllotheca indica is represented by broken and imperfect fragments of leaf-bearing stems4 ,the species is thus diagnosed by ,bunbury3--8,stem branched1 furrowed2 sheaths lax1 somewhat bell-shaped1 distinctly striated2 leaves narrow linear1 with a strong and distinct midrib1 widely spreading and often recurved1 nearly twice as long as the sheaths40 ,an examination of the specimens in the ,museum of the ,geological ,society of ,london1 on which this account was based1 has led me to the opinion that it is practically impossible to distinguish the ,indian examples from ,p4 australis described by ,brongniart#efg from ,new ,south ,wales4 ,the few specimens of the latter species which ,i have had an opportunity of examining bear out this view4 ,in the smaller branches the axis of ,p4 indica is divided into rather short internodes on which the ridges and grooves are faintly marked4 ,in the larger stems the ridges and grooves are much more prominent1 and continuous in direction from one internode to the next2 a few branches are given off from the nodes of some of the specimens4 ,the leaves are not very well preserved2 they consist of a narrow collar-like basal sheath divided up into numerous1 long and narrow segments1 which are several times as long as the breadth of the sheath1 and not merely twice as long as ,bunbury described them4 ,each leaf-sheath has the form of a very shallow cup-like rim clasping the stem at a node1 with long free spreading segments which are often bent back in their distal region4 ,the general habit of the leafy branches appears to be identical with that of ,p4 australis as figured by ,mc,coy4 ,prof4 ,zeiller informs me that in the type-specimen on which ,brongniart founded the species1 ,p4 australis1 the sheath appears to be closely applied to the stem with a verticil of narrow spreading segments radiating from its margin4 ,it may be1 therefore1 that in the ,australian form there was not such an open and cup-like sheath as in ,p4 indica2 but it would be difficult1 without better material before us1 to feel confidence in any well marked specific distinctions between the ,indian and ,australian ,phyllothecas4 ,on the broader stems1 such as that of fig4 #fg1 we have clearly marked narrow grooves and broader and slightly convex ridges1 which present an appearance identical with that of some ,calamitean stems4 ,in the specimen figured by ,bunbury#efh in his ,pl4 ,x1 fig4 #f1 there is a circular depression on the line of the node which represents the impression of the basal end of a branch2 on the edges of the node there are indications of two other lateral branches4 ,the nature of this stem-cast points umnistakeably to a woody stem like that of ,calamites4 ,the precise meaning of the ridges and grooves on the cast is described in the ,chapter dealing with ,calamitean plants4 ,sidenote3 ,,calamocladus4 ,grand',eury#efi in his monograph on the coal-basin of ,gard1 has recently described under the name of ,calamocladus frondosus what he believes to be the leaf-bearing axes of a ,calamitean plant4 ,the thicker branches are almost exactly identical in appearance with the broader specimens of ,phyllotheca4 ,the finer branches of ,calamocladus bear cup-like leaf-sheaths which are divided into long and narrow recurved segments 7fig4 #fg1 ,b71 precisely as in ,phyllotheca4 ,these comparisons lead one to the opinion that the ,phyllotheca of ,australia and ,india may be a close ally of the ,permo-,carboniferous ,calamitean plants4 ,the form of the leaf-whorls of ,annularia 7,calamarian leaf-bearing branches7 and of ,calamocladus is of the same type as in ,phyllotheca2 the character of the medullary casts is also the same4 ,the nature of the fertile shoot of ,phyllotheca described by ,schmalhausen from ,siberia1 with its alternating whorls of sterile and fertile leaves1 is another point of agreement between this genus and ,calamitean plants4 ,an ,equisetaceous species has been described from the ,newcastle ,coal-,measures of ,australia by ,etheridge#egj in which there are two forms of leaves1 some of which closely resemble those of ,phyllotheca indica1 while others are compared with the sterile bracts of ,cingularia1 a ,calamitean genus instituted by ,weiss#ega4 ,when we turn to other recorded forms of ,phyllotheca many of them appear on examination to have been placed in this genus on unsatisfactory grounds4 ,heer figures several stem fragments from the ,jurassic rocks of ,siberia as ,p4 ,sibirica ,heer#egb1 and it was the resemblance between this form and the ,english ,equisetites lateralis which led to the substitution of ,phyllotheca for ,equisetites in the latter species4 ,without examining ,heer's material it is impossible to criticise his conclusions with any completeness1 but several of his specimens1 appear to possess leaf-sheaths more like those of ,equisetum than of ,phyllotheca4 ,the frequent occurrence of isolated diaphragms and the comparatively long acuminate teeth of the leaf-sheath afford obvious points of resemblance to ,equisetites lateralis4 ,some of the examples figured by ,heer appear to be stem fragments1 with numerous long and narrow filiform leaves different in appearance from those of other specimens which he figures4 ,it may be that some of the less distinct pieces of stems are badly torn specimens in which the internodes have been divided into filiform threads4 ,heer also figures a fertile axis associated with the sterile stems1 and this does not1 as ,heer admits1 show the alternating sterile bracts such as ,schmalhausen has described4 ,so far as it is possible to judge from an examination of ,heer's figures and a few specimens from ,siberia in the ,british ,museum--and this is by no means a safe basis on which to found definite opinions--there appears to be little evidence in favour of separating the fossils described as ,phyllotheca ,sibirica from ,equisetites4 ,this ,siberian form may indeed be specifically identical with ,equisetites lateralis ,phill4 ,various species of ,phyllotheca have been described from ,jurassic and ,upper ,palaeozoic rocks in ,australia4 ,some of these possess cup-like leaf-sheaths1 and in the case of the thicker specimens they show continuous ridges and grooves on the internodes1 as well as a habit of branching similar to that in some of the ,italian ,phyllothecas4 ,in some of the stems it is however difficult to recognise any characters which justify the use of the term ,phyllotheca4 ,a fragment figured by ,tenison-,woods#egc as a new species of ,phyllotheca1 ,p4 carnosa1 from ,ipswich1 ,queensland1 affords an example of the worthless material on which species have not infrequently been founded4 ,the author of the species describes his single specimen as a 8faint impression02 the figure accompanying his description suggests a fragment of some coniferous branch1 as ,feistmantel has pointed out in his monograph on ,australian plants4 ,it is important that a thorough comparative examination should be made of the various fossil ,phyllothecas with a view to determine their scientific value1 and to discover how far the separation of ,phyllotheca and ,equisetites is legitimate in each case4 ,there is too often a tendency to allow geographical distribution to decide the adoption of a particular generic name1 and this seems to have been especially the case as regards several ,mesozoic and ,palaeozoic ,southern ,hemisphere plants4 ,the geological and geographical range of ,phyllotheca is a question of considerable interest1 but as already pointed out it is desirable to carefully examine the various records of the genus before attempting to generalise as to the range of the species4 ,phyllotheca is often spoken of as a characteristic member of the ,glossopteris ,flora of the ,southern ,hemisphere1 and its geological age is usually considered to be ,mesozoic rather than ,palaeozoic4 ,c4 ,schizoneura4 ,the plants included under this genus were originally designated by ,brongniart#egd ,convallarites and classed as ,monocotyledons4 ,some years later ,schimper and ,mougeot#ege had the opportunity of examining more perfect material from the ,bunter beds of the ,vosges1 and proposed the new name ,schizoneura in place of ,brongniart's term1 on the grounds that the specimens were in all probability portions of ,equisetaceous stems1 and not ,monocotyledons4 ,our knowledge of this genus is very limited1 but the characteristics are on the whole better defined than in the case of ,phyllotheca4 ,the following diagnosis illustrates the chief features of ,schizoneura4 ,hollow stems with nodes and internodes as in ,equisetum2 the surface of the internodes is traversed by regular ridges and grooves1 which are continuous and not alternate in their course from one internode to the next4 ,the leaf-sheaths are large and consist of several coherent segments2 the sheaths are usually split into two or more elongate ovate lobes1 and each lobe contains more than one vein4 ,fertile shoots are unknown4 ,two of the best known and most satisfactory species are ,schizoneura gondwanensis ,feist4 and ,s4 paradoxa ,schimp4 and ,moug4 ,schizoneura gondwanensis ,feist4 ,fig4 #fi1 ,a and ,b4 ,this species is represented by numerous specimens from the ,lower ,gondwana rocks of ,india#egf2 it is characterised by narrow articulated stems which bear large leaf-sheaths at the nodes4 ,the sheaths may have the form of two large and spreading elongate-oval lobes1 each of which is traversed by several veins 7fig4 #fi1 ,b71 or the lobes may be further dissected into long linear single-veined segments1 as in fig4 #fi1 ,a4 ,it is supposed that in the young condition each node bears a leaf-sheath consisting of laterally coherent segments which1 as development proceeds1 split into two or more lobes4 ,feistmantel records this species from the ,talchir1 ,damuda and ,panchet divisions of the ,lower ,gondwana series of ,india2 these divisions are regarded as equivalent to the ,permo-,carboniferous and ,triassic rocks of ,europe4 ,the two specimens shown in fig4 #fi are from the ,lower ,gondwana rocks of the ,raniganj ,coal-field1 ,india4 ,as already pointed out#egg1 some of the specimens of flat and broader stems referred by ,feistmantel to ,schizoneura are identical in appearance with stems which have been described from ,india and elsewhere as species of ,phyllotheca4 ,illustration3 ,,fig4 #fi4 ,schizoneura gondwanensis ,feist4 7,after ,feistmantel2 slightly reduced47 ,there are a few specimens of ,s4 gondwanensis in the ,british ,museum1 but the genus is poorly represented in ,european collections4 ,a similar plant was described in #ahdd by ,schimper and ,mougeot#egh from the ,bunter rocks of the ,vosges as ,schizoneura paradoxa4 ,this species bears a very close resemblance to the ,indian forms1 and indeed it is difficult to point to any distinction of taxonomic importance4 ,feistmantel considers that the ,european plant has rather fewer segments in the leaf-sheaths1 and that the ,indian plant had somewhat stronger stems4 ,both of these differences are such as might easily be found on branches of the same species4 ,it is1 however1 interesting to notice the very close resemblance between the ,lower ,trias ,european plant and the somewhat older member of the ,glossopteris flora recorded from ,india and other regions1 which probably once formed part of that ,southern ,hemisphere ,continent which is known as ,gondwana ,land#egi4 ,,chapter ,x4 ,i4 ,,equisetales 7continued74 7,,calamarieae47 ,in order to minimise repetition and digression the following account of the ,calamarieae is divided into sections1 under each of which a certain part of the subject is more particularly dealt with4 ,after a brief sketch of the history of our knowledge of ,calamites1 and a short description of the characteristics of the genus1 the morphological features are more fully considered4 ,a description of the most striking features of the better known ,calamitean types is followed by a short discussion on the question of nomenclature and classification1 and reference is made to the manner of occurrence of ,calamites and to some of the possible sources of error in identification4 ,d4 ,,calamites4 ,i4 ,historical ,sketch4 ,in the following account of the ,calamarieae the generic name ,calamites is used in a somewhat comprehensive sense4 ,as previous writers have pointed out1 it is probable that under this generic name there may be included more than one type of plant worthy of generic designation4 ,owing to the various opinions which have been held by different authors1 as to the relationship and botanical position of plants now generally included in the ,calamarieae1 there has been no little confusion in nomenclature4 ,facts as to the nature of the genus ,calamites have occasionally to be selected from writings containing many speculative and erroneous views1 but the data at our disposal enable us to give a fairly complete account of the morphology of this ,palaeozoic plant4 ,in the earliest works on fossil plants we find several figures of ,calamites1 which are in most cases described as those of fossil reeds or grasses4 ,the ,herbarium diluvianum of ,scheuchzer#ehj contains a figure of a ,calamitean cast which is described as probably a reed4 ,another specimen is figured by ,volkmann#eha in his ,silesia subterranea and compared with a piece of sugar-cane4 ,a similar flattened cast in the old ,woodwardian collection at ,cambridge is described by ,woodward#ehb as 8part of a broad long flat leaf1 appearing to be of some ,iris1 or rather an ,aloe1 but 'tis striated without40 ,schulze#ehc1 one of the earlier ,german writers1 figured a ,calamitean branch bearing verticils of leaves1 and described the fossil as probably the impression of an ,equisetaceous plant4 ,it has been pointed out by another ,german writer that the ,equisetaceous character of ,calamites was recognised by laymen many years before specialists shared this view4 ,one of the most interesting and important of all the older records of ,calamites is that published by ,suckow#ehd in #aghd4 ,suckow is usually quoted as the author of the generic name ,calamites2 he does not attempt any diagnosis of the plant1 but merely speaks of the specimens he is describing as 8,calamiten40 ,the examples figured in this classic paper are characteristic casts from the ,coal-,measures of ,western ,germany4 ,suckow describes them as ribbed stems1 which were found in an oblique position in the strata and termed by the workmen ,jupiter's nails 78,ngel074 ,previous writers had regarded the fossils as casts of reeds1 but ,suckow correctly points out that the ribbed character is hardly consistent with the view that the casts are those of reeds or grasses4 ,he goes on to say that the material filling up the hollow pith of a reed would not have impressed upon it a number of ribs and grooves such as occur on the ,calamites4 ,he considers it more probable that the casts are those of some well-developed tree1 probably a foreign plant4 ,equisetum giganteum ,l4 is mentioned as a species with which ,calamites may be compared1 although the stem of the ,palaeozoic genus was much larger than that of the recent ,horse-tail4 ,the tree of which the ,calamites are the casts must1 he adds1 have possessed a ribbed stem1 and the bark must also have been marked by vertical ribs and grooves on its inner face4 ,it is clear1 therefore1 that ,suckow inclined to the view that ,calamites should be regarded as an internal cast of a woody plant4 ,such an interpretation of the fossils was generally accepted by palaeobotanists only a comparatively few years ago1 and the first suggestion of this view is usually attributed to ,germar1 ,dawes1 and other authors who wrote more than fifty years later than ,suckow4 ,one of the earliest notices of ,calamites in the present century is by ,steinhauer#ehe1 who published a memoir in the ,transactions of the ,american ,philosophical ,society in #ahah on ,fossil reliquia of unknown vegetables in the ,carboniferous rocks4 ,he gives some good figures of ,calamitean casts under the generic name of ,phytolithus1 one of those general terms often used by the older writers on fossils4 ,among ,english authors1 ,martin#ehf may be mentioned as figuring casts of ,calamites1 which he describes as probably grass stems4 ,by far the best of the earlier figures are those by ,artis#ehg in his ,antediluvian ,phytology4 ,this writer does not discuss the botanical nature of the specimens beyond a brief reference to the views of earlier authors4 ,adolphe ,brongniart#ehh1 writing in #ahbb1 expresses the opinion that the ,calamites are related to the genus ,equisetum1 and refers to ,m4 de ,candolle as having first suggested this view4 ,in a later work ,brongniart#ehi includes species of ,calamites as figured by ,suckow1 ,schlotheim1 ,sternberg and ,artis in the family ,equisetaceae4 ,lindley and ,hutton#eij give several figures of ,calamites in their ,fossil flora1 but do not commit themselves to an ,equisetaceous affinity4 ,an important advance was made in #ahce by ,cotta#eia1 a ,german writer1 who gave a short account of the internal structure of some ,calamite stems1 which he referred to a new genus ,calamitea4 ,the ,british ,museum collection includes some silicified fragments of the stems figured and described by ,cotta in his ,dendrolithen4 ,some of the specimens described by this author as examples of ,calamitea have since been recognised as members of another family4 ,sidenote3 ,,petzholdt ,,and ,,unger4 ,in #ahdj ,unger#eib published a note on the structure and affinities of ,calamites1 and expressed his belief in the close relationship of the ,palaeozoic plant and recent ,horse-tails4 ,an important contribution to our knowledge of ,calamites was supplied by ,petzholdt#eic in #ahda4 ,his main contention was the ,equisetaceous character of this ,palaeozoic genus4 ,the external resemblance between ,calamite casts and ,equisetum stems had long been recognised1 but after ,cotta's account of the internal structure it was believed that the apparent relation between ,equisetum and ,calamites was not confirmed by the facts of anatomy4 ,petzholdt based his conclusions on certain partially preserved ,permian stems from ,plauenscher ,grund1 near ,dresden4 ,although his account of the fossils is not accurate his general conclusions are correct4 ,the specimens described by ,petzholdt differ from the common ,calamite casts in having some carbonised remnants of cortical and woody tissue4 ,a transverse section of one of the ,plauenscher ,grund fossils is shown in fig4 #gj4 ,the irregular black patches were described by ,petzholdt as portions of cortical tissue1 while he regarded the spaces as marking the position of canals like the vallecular canals in an ,equisetum4 ,our more complete knowledge of the structure of a ,calamite stem enables us to correlate the patches in which no tissue has been preserved with the broad medullary rays1 which separated the wedge-shaped groups of xylem elements2 the latter being more resistant were converted into a black coaly substance1 while the cells of the medullary rays left little or no trace in the sandstone matrix4 ,the thin black line1 which forms the limit of the drawing in fig4 #gj1 external to the carbonised wood1 no doubt marks the limit of the cortex1 and the appendage indicated in the lower part of the figure may possibly be an adventitious root4 ,it is interesting to note that ,unger#eid in #ahdd expressed the opinion1 which we now know to be correct1 that the coaly mass in the specimens described by ,petzholdt represented the wood1 and that there was no proof of the existence of canals in the cortex as ,petzholdt believed4 ,illustration3 ,,fig4 #gj4 ,transverse section of a ,calamite stem1 showing carbonised remnants of secondary wood4 ,from a specimen 7no4 #djicd71 presented to the ,british ,museum by ,dr ,petzholdt from ,plauenscher ,grund1 ,dresden4 nat4 size4 ,turning to ,brongniart's later work#eie we find an important proposal which led to no little controversy4 ,while retaining the genus ,calamites for such specimens as possess a thin bark and a ribbed external surface1 showing occasional branch-scars at the nodes1 and having such characters as warrant their inclusion in the ,equisetaceae1 he proposes a second generic name for other specimens which had hitherto been included in ,calamites4 ,the fossils assigned to his new genus ,calamodendron are described as having a thick woody stem1 and as differing from ,equisetum in their arborescent nature4 ,brongniart's genus ,calamodendron is made to include the plants for which ,cotta instituted the name ,calamitea1 and it is placed among the ,gymnosperms4 ,this distinction between the ,vascular ,cryptogam ,calamites and the supposed ,gymnosperm ,calamodendron is based on the presence of secondary wood in the latter type of stem4 ,the prominence formerly assigned to the power of secondary thickening possessed by a plant as a taxonomic feature1 is now known to have been the result of imperfect knowledge4 ,the occurrence of a cambium layer and the ability of a plant to increase in girth by the activity of a definite meristem1 is a feature which some recent ,vascular ,cryptogams#eif share with the higher plants2 and in former ages many of the ,pteridophytes possessed this method of growth in a striking degree4 ,although ,brongniart's distinction between ,calamites and ,calamodendron has not been borne out by subsequent researches1 the latter term is still used as a convenient designation for a special type of ,calamitean structure4 ,one of the earliest accounts of the anatomy of ,calamodendron stems is by ,mougeot#eig1 who published figures and descriptions of two species1 ,calamodendron striatum and ,c4 bistriatum4 ,some years later ,gppert#eih1 who was one of the greatest of the older palaeobotanists1 instituted another genus1 ,arthropitys#eii1 for certain specimens of silicified stems from the ,permian rocks of ,chemnitz in ,saxony1 which ,cotta had previously placed in his genus ,calamitea under the name of ,calamitea bistriata#fjj4 ,gppert rightly decided that the plants so named by ,cotta differed in important histological characters from other species of ,calamitea4 ,the generic name ,arthropitys has been widely adopted for a type of ,calamitean stem characterised by definite structural features4 ,the great majority of the petrified ,calamite stems found in the ,english ,coal-,measures belong to ,gppert's ,arthropitys4 ,sidenote3 ,,williamson4 ,the next proposal to be noticed is one by ,williamson#fja in #ahfh2 he instituted the generic name ,calamopitys for a few examples of ,english stems1 which differed in the structure of the wood and primary medullary rays from previously recorded types4 ,we have thus four names which all stand for generic types of ,calamitean stems4 ,of these ,calamodendron and ,arthropitys are still used as convenient designations for stems with well-defined anatomical characters4 ,the genus ,calamitea is no longer in use1 and ,williamson's name ,calamopitys had previously been made use of by ,unger#fjb for plants which do not belong to the ,calamarieae4 ,as it is convenient to have some term to apply to such stems as those which ,williamson made the type of ,calamopitys1 the name ,arthrodendron is suggested by my friend ,dr ,scott#fjc as a substitute for ,williamson's genus4 ,the twofold division of the ,calamites instituted by ,brongniart has already been alluded to1 and for many years it was generally agreed that both ,pteridophytes and ,gymnosperms were represented among the ,palaeozoic fossils known as ,calamites4 ,the work of ,prof4 ,williamson was largely instrumental in proving the unsound basis for this artificial separation2 he insisted on the inclusion of all ,calamites in the ,vascular ,cryptogams1 irrespective of the presence or absence of secondary wood4 ,by degrees the adherents of ,brongniart's views acknowledged the force of the ,english botanist's contention4 ,it is one of the many signs of the value of ,williamson's work that there is now almost complete accord among palaeobotanical writers as to the affinities of ,calamitean plants4 ,in the following account of the ,calamites1 the generic name ,calamites is used in a wide sense as including stems possessing different types of internal structure2 when it is possible to recognise any of these structural types the terms ,calamodendron1 ,arthropitys or ,arthrodendron are used as subgenera4 ,the reasons for this nomenclature are discussed in a later part of the ,chapter4 ,this term was originally applied ,genus ,calamites1 ,suckow1 #agad to the common pith-casts of ,calamitean stems1 without reference to internal structure4 ,subgenera ,calamodendron1 ,brongniart1 #ahdi ,these names have ,arthropitys ,gppert1 #ahfd primarily reference ,arthrodendron ,scott #ahig to internal 7 ,calamopitys ,williamson1 #ahga7 structure4 ,,ii4 ,description of the anatomy of ,calamites4 a4 ,stems4 b4 ,leaves4 c4 ,roots4 d4 ,cones4 ,no fossils are better known to collectors of ,coal-,measure plants than the casts and impressions of the numerous species of ,calamites4 ,in sandstone quarries of ,upper ,carboniferous rocks there are frequently found cylindrical or somewhat flattened fossils1 varying from one to several inches in diameter1 marked on the surface by longitudinal ridges and grooves1 and at more or less regular intervals by regular transverse constrictions4 ,similar specimens are still more abundant as flattened casts in the blocks of shale found on the rubbish heaps of collieries4 ,the sandstone casts are often separated from the surrounding rock by a loose brown or black crumbling material1 and the specimens in the shale are frequently covered by a thin layer of coal4 ,most of the earlier writers regarded such specimens as the impressions of the ribbed stems of plants similar to or identical with reeds or grasses4 ,suckow1 and afterwards ,dawes and others1 expressed the opinion that the ordinary ,calamite cast represented a hardened mass of sand or marl1 which had filled up the pith of a stem either originally fistular or rendered hollow by decay4 ,the investigation of the internal structure confirmed this view1 and proved that the surface-features of a ,calamite stem do not represent the external markings of the original plant1 but the form of the inner face of the cylinder of wood4 ,the ribs represent the medullary rays of the original stem or branch1 and the intervening grooves mark the position of the strands of xylem which are arranged in a ring round a large hollow pith#fjd4 ,with this brief preliminary account we may pass to a detailed description of the anatomical characters of ,calamites4 ,the genus ,calamites may be briefly defined as follows3-- ,arborescent plants reaching a height of several meters1 and having a diameter of proportional size4 ,in habit of growth the ,calamites bore a close resemblance to ,equisetum2 an underground rhizome giving off lateral branches and erect aerial shoots bearing branches1 either in whorls from regularly recurring branch-bearing nodes1 or two or three from each node2 and in some cases the stems bore occasional branches from widely separated nodes4 ,the leaves were disposed in whorls either as star-shaped verticils on slender foliage shoots1 or in the form of a circle of long narrow leaves on the node of a thicker branch4 ,adventitious roots were developed from the nodal regions of underground and aerial stems4 ,the cones had the form of long and narrow strobili consisting of a central axis bearing whorls of sterile and fertile appendages2 the latter in the form of sporangiophores bearing groups of sporangia4 ,the strobili were heterosporous in some cases1 isosporous in others4 ,the stems had a large hollow pith bridged across by a transverse diaphragm at the nodes in the centre of the single stele2 the latter consisted of a ring of collateral bundles separated from one another by primary medullary rays4 ,each group of xylem was composed of spiral1 annular1 scalariform and occasionally reticulate tracheids1 the position of the protoxylem being marked by a longitudinal carinal canal4 ,the shoots and roots grew in thickness by means of a regular cambium layer4 ,the cortex consisted of parenchymatous and sclerenchymatous cells1 with scattered secretory sacs4 ,the increase in girth of the central cylinder was often accompanied by a considerable development of cortical periderm4 ,the roots differed from the shoots in having no carinal canals1 and in the possession of a solid pith and centripetally developed primary xylem groups alternating with strands of phloem4 ,the above incomplete diagnosis includes only some of the more important structural features of the genus4 ,thanks to the researches begun by the late ,mr ,binney of ,manchester and considerably extended by ,carruthers1 ,williamson and later investigators1 we are now in a position to give a fairly complete account of ,calamites4 ,the type of stem most frequently met with in a petrified condition in the ,english rocks is that to which ,gppert applied the name ,arthropitys1 and it is this subgenus that forms the subject of the following description4 ,our knowledge of ,calamitean anatomy is based on the examination of numerous fragments of petrified twigs and other portions of different specific types of the genus4 ,it is seldom possible to differentiate specifically between the isolated fragments of stems and branches which are met with in calcareous or siliceous nodules4 ,as so frequently happens in fossil-plant material1 large specimens showing good surface features and broken fragments with well-preserved internal structure have to be dealt with separately4 ,sidenote3 ,,young ,,stem4 a4 ,stems4 ,a transverse section of a young twig1 such as is represented in fig4 #ga1 illustrates the chief characteristics of the primary structure of a young branch of ,calamites4 ,the figure has been drawn from a section originally described by ,hick#fje in #ahid4 ,a very young ,calamite twig bears an exceedingly close resemblance to the stem of a recent ,equisetum4 ,the axial region of the stem may be occupied by parenchymatous cells1 or the absence of cells in the centre may indicate the beginning of the gradual formation of the hollow pith1 which is one of the characteristics of ,calamites4 ,the student of petrified ,palaeozoic plants must constantly be on his guard against the possible misinterpretation of ,stigmarian #8rootlets1' which are frequently found in intimate association with fossil tissues4 ,the intrusion of these rootlets is admirably illustrated by a section of a ,calamite stem in the ,williamson ,collection 7,no4 #aeeh7 in which the hollow pith1 #b cm4 broad1 contains more than a dozen ,stigmarian appendages4 ,illustration3 ,,fig4 #ga4 ,transverse section of a young ,calamite stem4 c1 carinal canals2 mr1 primary medullary rays2 a1 b1 and d1 cortex2 e1 epidermis4 ,from a section in the ,manchester ,museum1 ,owens ,college1 #fj4 ,in the figured specimen of a ,calamite twig 7fig4 #ga7 there is a clearly marked differentiation into a cortical region and a large stele or central cylinder4 ,the pith-cells are already partially disorganised1 but there still remain a few fairly large parenchymatous cells internal to the ring of vascular bundles4 ,the few irregular projections into the cavity of the large pith consist of small fragments of cells1 which may be the result of fungal action4 ,mycelia of fungi are occasionally met with in the tissues of older ,calamite stems4 ,the position of the primary xylem groups is shown by the conspicuous and regularly placed canals1 c2 these have been formed in precisely the same manner as the corresponding spaces in an ,equisetum stem1 and they are spoken of in both genera as the carinal canals4 ,each canal owes its origin to the disorganization and tearing apart of the protoxylem elements and the surrounding cells4 ,this may be occasionally seen in examples of very young ,calamites2 the canals of a young twig often contain apparently isolated rings which are coils of elongated spiral threads4 ,fig4 #gb1 ,b represents the canal of a twig1 cut in an oblique direction1 in which the remains of spiral tracheids are distinctly seen4 ,in the stem of fig4 #ga the development has not advanced far enough to enable us to clearly define the exact limits of each xylem strand4 ,the smaller elements bordering the canals constitute the primary xylem1 they are fairly distinct on the outer margin of some of the canals seen in the section4 ,between the small patches of primary xylem the outward extensions of the parenchyma of the pith constitute the primary medullary rays1 mr4 ,the distinct line encircling the canals and primary xylem has been described by ,hick as marking the position of the endodermis1 but it may possibly owe its existence to the tearing of the tissues along the line where cambial activity is just beginning4 ,this layer of delicate dividing cells would constitute a natural line of weakness4 ,external to this line we have a zone of tissue a1 d1 containing here and there larger cells with black contents1 which are no doubt secretory sacs4 ,it is impossible to distinguish with certainty any definite phloem groups1 but in other specimens these have been recognised immediately external to each primary xylem group2 the bundles were typically collateral in structure4 ,towards the periphery of the twig the preservation is much less perfect2 the outer portion of the inner cortex1 d1 consists of rather smaller and thicker-walled cells1 but this is succeeded by an ill-defined zone containing a few scattered cells1 b1 which have been more perfectly preserved4 ,the twig is too young to show any secondary tissue in the cortex2 but the tangential walls in some of the cortical cells afford evidence of meristematic activity1 which probably represents the beginning of cork-formation4 ,the limiting line1 e1 possibly represents the cuticularised outer walls of an epidermal layer4 ,the irregularly wavy character of the surface of the specimen is probably the result of shrinking1 and does not indicate original surface features4 ,sidenote3 ,,vascular ,,system4 ,in examining sections of calcareous nodules from the coal seams one meets with numerous fragments of small ,calamitean twigs with little or no secondary wood2 in some of these there is a small number of carinal canals1 in others the canals are much more abundant4 ,the former probably represent the smaller ramifications of a plant1 and the latter may be regarded as the young stages of branches capable of developing into stout woody shoots#fjf4 ,longitudinal sections of small branches teach us that the xylem elements next the carinal canals are either spiral or reticulate in character1 the older tracheids being for the most part of the scalariform type1 with bordered pits on the radial walls4 ,this and other histological characters are admirably shown in the illustrations accompanying ,williamson and ,scott's memoir on ,calamites4 ,the student should treat the account of the anatomy of ,calamites given in these pages as introductory to the much more complete description by these authors4 ,they thus describe the course of the vascular bundles in a ,calamitean branch3-- 8,the bundle-system of ,calamites bears a general resemblance to that of ,equisetum4 ,a single leaf-trace enters the stem from each leaf1 and passes vertically downwards to the next node4 ,in the simplest cases the bundle here forks1 its two branches attaching themselves to the alternating bundles which enter the stem at this node4 ,in other cases both the forks attach themselves to the same bundle1 so that1 in this case1 there is no regular alternation4 ,in other cases1 again1 the bundle runs past one node without forking1 and ultimately forms a junction with the traces of the second node below its starting-point4 ,these variations may all occur in the same specimen4 ,the xylem at the node usually forms a continuous ring1 for where the regular dichotomous forks of the bundles are absent their place is usually taken by anastomoses#fjg40 ,as in ,equisetum1 the xylem at the nodes possesses certain characteristic features which distinguish it from the internodal strands4 ,it has already been pointed out that the xylem of ,equisetum increases in breadth at the nodes 7p4 #bea1 fig4 #ee1 #d72 the same is true of ,calamites4 ,in fig4 #gb1 ,c1 we have part of a radial section of a ,calamite twig in which the broad mass of short nodal tracheids is clearly shown2 this nodal wood forms a prominent projection towards the pith4 ,in the lower part of the section the remains of some spiral protoxylem tracheids are seen in a carinal canal4 ,illustration3 ,,fig4 #gb4 ,a4 ,external xylem elements and cambium1 c1 with imperfect phloem1 #ajj4 ,b4 ,carinal canal containing protoxylem1 px4 #fe4 ,c4 ,radial longitudinal section through nodal xylem1 px4 #ce4 ,d4 ,phloem elements2 s1 sieve-tubes2 p1 p1 parenchymatous cells4 7,a-,c4 ,after ,williamson and ,scott4 ,d4 ,after ,renault47 ,the tracheids of the nodal wood are often reticularly pitted1 and so differ in appearance from the ordinary scalariform elements4 ,it is rare to find the phloem clearly preserved1 but in specimens where it has been possible to examine this portion of the vascular bundles1 it is found to consist of elongated cambiform cells and sieve-tubes4 ,an unusually perfect specimen has been described by ,renault#fjh in which the phloem elements are preserved in silica4 ,fig4 #gb1 ,d1 is copied from one of ,renault's drawings1 the sieve-tubes1 s1 s1 show several distinct sieve-plates on the lateral walls of the tubes1 reminding one to some extent of the sieve-tubes in a ,bracken ,fern4 ,the cells1 p1 p1 associated with the sieve-tubes are square-ended elongated parenchymatous elements4 ,another characteristic feature illustrated by longitudinal sections is the nodal diaphragm2 except in the smallest branches the interior of each internode is hollow1 and the ring of vascular bundles is separated from the pith-cavity by a band of parenchymatous tissue4 ,at each node this parenchyma extends across the central cavity in the form of a nodal diaphragm1 as in the stem of ,equisetum4 ,by far the greater number of the petrified fragments of ,calamites afford proof of cambial activity1 and possess obvious secondary tissues4 ,in exceptionally perfect specimens the xylem tracheids are found to be succeeded externally by a few flattened thin-walled cells which are in a meristematic condition 7fig4 #gb1 ,a1 c72 these constitute the cambium zone1 and it is the secondary structure that results from the activity of the meristematic cells that we have now to consider4 ,sidenote3 ,,secondary ,,thickening4 ,in petrified examples of branches in which the secondary thickening has reached a fairly advanced stage1 the wood is usually the outermost tissue preserved1 the more external tissues having been detached along the line of cambium cells4 ,it is only in a few cases that we are able to examine all the tissues of older examples4 ,the specimen represented in fig4 #gc illustrates very clearly the extension of the hollow pith up to the inner surface of the vascular ring2 the disorganisation of the pith-cells which had already begun in the twig of fig4 #ga has here advanced much further4 ,the bluntly rounded projections represent the prominent primary xylem strands1 each of which is traversed by the characteristic carinal canal4 ,alternating with the wedge-shaped groups of secondary xylem1 x1 we have the broad principal medullary rays1 mr1 which become slightly narrower towards the outside4 ,the inner face of each of these wide rays has a concave form1 due to the less resistent nature of the medullary-ray cells as compared with the stronger xylem4 ,the regularly sinuous form of the inner face of the vascular cylinder enables one to realise how the ,calamite-casts 7figs4 #hb1 #ii1 and #aja7 have come to have the regular ridges and grooves on their surface4 ,the broad ridges on the cast mark the position of the wide medullary rays1 while the grooves correspond to the more prominent ends of the vascular strands4 ,the tissues external to the wood have not been preserved in the example shown in fig4 #gc4 ,some silicified specimens described by ,stur#fji from ,bohemia and now in the ,museum of the ,austrian ,geological ,survey1 ,vienna1 admirably illustrate the connection between the surface features of a ,calamite cast and the anatomy of the stem4 ,illustration3 ,,fig4 #gc4 ,transverse section of a ,calamite stem4 mr1 medullary ray4 ,after ,williamson4 x1 x1 xylem4 7,no4 #aicc ,a4,a4 in the ,williamson ,collection47 ,sidenote3 ,,arthropitys4 ,in the large section of a calcareous nodule diagrammatically shown in fig4 #ag ,,ii4 7p4 #he7 the secondary wood of a slightly flattened ,calamite is the most prominent plant fragment4 ,the pith-cavity has been almost obliterated by the lateral compression of the woody cylinder1 but the presence of the carinal canals along the inner edge of the wood may still be readily recognised4 ,the appearance presented by a transverse section of the secondary wood of a ,calamite is that of regular radial series of rather small rectangular tracheids1 with occasional secondary medullary rays consisting of narrow and radially elongated parenchymatous cells4 ,the principal rays#faj in the ,arthropitys type of a ,calamite stem are often found to gradually decrease in breadth as they pass into the secondary wood1 until in the outer portion of the wood the primary medullary rays are practically obliterated by the formation of interfascicular xylem4 ,in fig4 #gd1 ,a1 we have a portion of a single xylem group of a thick woody stem4 ,the stem from which the figure has been drawn was originally described by ,binney#faa as ,calamodendron commune2 we now recognise it as a typical example of the subgenus ,arthropitys4 ,the specific term communis was used by ,ettingshausen#fab in #ahee in a comprehensive sense to include more than twenty species of the genus ,calamites1 but since ,binney's use of the term it has come to be associated with a definite type of ,arthropitys stem1 in which the primary medullary rays decrease rapidly in breadth towards the periphery of the wood4 ,the wood of ,binney's stem#fac measures #be cm4 across1 but the pith-cavity has been crushed to the limits of a narrow band represented in the figure by the shaded portion4 ,the strand of cells1 s1 in the pith is a portion of a ,stigmarian appendage 78rootlet071 which penetrated into the hollow stem of the ,calamite and became petrified by the same agency to which the preservation of the stem is due4 ,these intruded ,stigmarian appendages are of constant occurrence in the calcareous nodules2 their intimate association with the tissues of other plants is often a serious source of error in the identification of petrified tissues4 ,the inner portion of one of the xylem groups is shown in fig4 #gd1 ,a4 ,external to the carinal canal1 the xylem tracheids are disposed in regular series and associated with numerous narrow secondary medullary rays4 ,the width of the xylem wedge increases gradually as we pass outwards1 this is due to the formation of interfascicular xylem1 which in the more peripheral portion of the stem extends across the primary medullary rays4 ,the few primary medullary-ray cells shown in the drawing illustrate the characteristic tangentially elongated form and large size of the parenchymatous elements4 ,williamson and ,scott have pointed out that the tangentially elongated form of the medullary-ray cells is the result of active growth1 and not merely the expression of the tangential stretching of the stem consequent on secondary thickening4 ,illustration3 ,,fig4 #gd4 ,a4 ,transverse section of part of a ,calamite stem4 ,calamites 7,arthropitys7 communis 7,binney74 s1 ,stigmarian appendage4 x1 xylem4 ,from a specimen in the ,binney ,collection1 ,cambridge1 #ej4 ,b4 ,transverse section of a stem4 h1 hypodermal tissue2 c1 inner cortex4 ,from a specimen in the ,williamson ,collection 7no4 #fb74 #ce4 ,a glance at the complete transverse section of the stem1--of which a small portion is shown in fig4 #gd ,a1--suggests the existence of annual rings in the wood1 but this appearance of rings is merely the result of compression4 ,the secondary wood of a ,calamite does not exhibit any regular zones of growth comparable with the annual rings of our forest trees4 ,illustration3 ,,fig4 #ge4 ,longitudinal tangential section near the inner edge of the wood of the ,calamite of fig4 #gd4 x1 x1 secondary xylem and medullary rays2 m1 principal medullary ray4 ,from a section in the ,binney ,collection1 #ej4 ,before passing to other examples of ,calamitean stems1 reference may be made to the sections shown in figs4 #ge and #gf1 which illustrate some further points in the structure of ,binney's stems4 ,in fig4 #ge the xylem tracheids are shown at x1 and between them the secondary medullary rays present the appearance of long and narrow parenchymatous cells2 as the section is tangential the characteristic scalariform character of the tracheids is not shown1 the ladder-like bordered pits being confined to the radial walls of the tracheal elements4 ,the much greater length than breadth of the cells which form the rays associated with the xylem tracheids1 is a characteristic feature in ,calamitean stems4 ,the breadth of the principal ray1 m1 shows that the section has passed through the wood a short distance from the pith2 in a tangential section cut further into the wood the breadth of the principal rays would be considerably reduced4 ,the large medullary-ray tissue consists of square-walled parenchymatous cells4 ,the more highly magnified section1 in fig4 #gf1 shows a central group of parenchyma containing a few transversely cut tracheids1 but the two kinds of elements are not clearly differentiated in the figure2 this group of cells is an outgoing leaf-trace which is enclosed by the strongly curved tracheids of the stem4 ,the section is taken from the node of a stem where several leaf-trace bundles are passing out to a whorl of leaves2 the few cells intercalated between the tracheids belong to the parenchyma of the secondary medullary rays4 ,illustration3 ,,fig4 #gf4 ,longitudinal tangential section of the same ,calamite as that of figs4 #gd and #ge1 showing a leaf-trace and curved tracheids at a node4 ,from a section in the ,binney ,collection1 #ajj4 ,sidenote3 ,,arthropitys4 ,,surface ,,features4 ,in the small portion of a stem represented in fig4 #gd ,b1 the cortical tissues have been partially preserved2 at the inner edge1 next the hollow pith1 there are two xylem groups1 each with a carinal canal1 and between them is part of a broad 8principal0 medullary ray#fad4 ,the cambium has not been preserved1 but beyond this region we have some of the large cells1 c1 of the inner cortex2 these are followed by a few remnants of a smaller-celled tissue1 and external to this part of the cortex there is a series of triangular groups1 h1 consisting of small thick-walled cells alternating with spaces which were originally occupied by more delicate parenchyma4 ,the darker groups constitute hypodermal strands of mechanical tissue or stereome which lent support to the stem4 ,the surface of a stem possessing such supporting strands would probably assume a longitudinally wrinkled or grooved appearance on drying2 the intervening parenchyma1 contracting and yielding more readily1 would tend to produce shallow grooves alternating with the ridges above the stereome strands4 ,the complete section of the stem of which a small portion is shown in fig4 #gd ,b1 is figured by ,williamson#fae in his #abth memoir on ,coal-,measure plants4 ,the section was obtained from ,ashton-under-,lyne in ,lancashire2 it illustrates very clearly a method of preservation which is occasionally met with among petrified plants4 ,the walls of the various tissue elements are black in colour and somewhat ragged1 and the general appearance of the section is similar to that of a section of a charred piece of stem4 ,it is possible that the ,calamite twig was reduced to charcoal before petrifaction by a lightning flash or some other cause4 ,it is often said that the surface of a ,calamite stem was probably marked by regular ridges and grooves similar to those of the pith-cast1 and that such external features are connected with the arrangement of the tissues in the vascular cylinder4 ,the indication of grooves and ridges on the bark of fossil ,calamites is no doubt the result of the existence in the hypoderm of firm strands alternating with strands of less resistant cells4 ,it is very common to find ,calamite pith-casts covered with a layer of coal presenting a ribbed surface1 but this is simply due to the moulding of the coaly film on an internal pith-cast4 ,the broad grooves on such a specimen as that of fig4 #gg are1 on the other hand1 probably an indication of the existence of hypoderm bands similar to those in fig4 #gd ,b1 h4 ,the specimen from which fig4 #gg is drawn shows many interesting features4 ,the figure given by ,grand',eury1 of which fig4 #gg is a copy1 is somewhat idealised1 but the various surfaces can be made out in the fossil4 ,the surface of the coaly envelope surrounding the pith-cast1 a1 is distinctly grooved1 but the depressions have nothing to do with the surface features of the wood or the pith-cast2 they are no doubt due to the occurrence of alternating bands of thick- and thin-walled tissue in the hypodermal region of the cortex2 the peripheral strands of bast cells would stand out as prominent ribs as the stem tissue contracted during fossilisation4 ,at b 7fig4 #gg7 we have a view of the wood in which the position of the principal rays is indicated by fine longitudinal lines at regular intervals2 the oval projections just below the nodal line are probably the casts of infranodal canals 7cf4 p4 #cbd74 ,at a the characteristic pith-cast is seen with a small branch-scar on the node4 ,the scar on the middle node1 ,n #b1 is probably that of a root1 and a root ,r is still attached to the node1 ,n #c4 ,illustration3 ,,fig4 #gg4 ,portion of a ,calamite stem1 showing the surface of the bark1 c2 the wood1 b2 the surface of the pith-cast1 a4 ,n4#a-,n4#c4 ,nodes4 ,r4 ,root4 7,after ,grand',eury4 ,partially restored from a specimen in the cole des ,mines1 ,paris47 nat4 size4 ,sidenote3 ,,periderm ,,in ,,stems4 ,an interesting feature observed in some specimens of older ,calamite branches is the development of periderm or cork4 ,this is illustrated on a large scale by a unique specimen originally described by ,williamson in #ahghfaf4 ,figs4 #gh and #gi represent transverse and longitudinal sections of this stem4 ,this unusually large petrified stem was found in the ,coal-,measures of ,oldham1 in ,lancashire4 ,in the slightly reduced drawing1 fig4 #gh1 the large and somewhat flattened pith1 p1 #db cm4 in diameter1 is shown towards the bottom of the figure4 ,surrounding this we have #eh or #ei wedge-shaped projecting xylem groups and broad medullary rays2 the latter soon become indistinguishable as they are traced radially through the thick mass of secondary wood1 #e cm4 wide1 composed of scalariform tracheids and secondary medullary rays 7fig4 #gh1 #c74 ,the secondary wood presents the features characteristic of ,calamites 7,arthropitys7 communis 7,binney74 ,external to the wood there is a broken-up mass1 about #ee cm4 wide composed of regularly arranged 7fig4 #gh1 #b7 and rather thick-walled cells2 this consists of periderm1 a secondary tissue1 which has been developed by a cork-cambium during the increase in girth of the plant4 ,the more delicate cortical tissues have not been preserved1 and the more resistant portion of the bark has been broken up into small pieces of corky tissue1 among which are seen numerous ,stigmarian appendages1 pieces of sporangia and other plant fragments4 ,these associated structures cannot of course be shown in the small-scale drawing of the figure4 ,illustration3 ,,fig4 #gh4 #a4 ,transverse section of a thick ,calamite stem4 p1 pith2 x1 secondary wood2 c1 bark4 7 nat4 size47 #b4 ,periderm cells of bark4 #c4 ,xylem and medullary rays4 7#b and #c1 #hj47 ,from a specimen in the ,williamson ,collection 7no4 #gi74 ,in the radial longitudinal section 7fig4 #gi7 we see the pith with the projecting wood and the remains of a diaphragm at the node4 ,the mottled or watered appearance of the wood is due to numerous medullary rays which sweep across the tracheids4 ,the periderm elements1 as seen in longitudinal section1 are fibrous in form4 ,illustration3 ,,fig4 #gi4 ,longitudinal section of the specimen stem in fig4 #gh4 ,from a specimen in the ,williamson ,collection1 ,british ,museum 7no4 #hj74 nat4 size4 ,sidenote3 ,,callus ,,wood4 ,the development of cork in a younger ,calamite stem is clearly shown in a specimen described by ,williamson and ,scott in their ,memoir of #ahid4 ,in a transverse section of the stem several large cells of the inner cortex are seen to be in process of division by tangential walls1 and giving rise to radially arranged periderm tissue#fag4 ,the section diagrammatically sketched in fig4 #hj is that of a ,calamite twig in which the wood appears to have been injured1 and the wound has been almost covered over by the formation of callus wood4 ,the young trees in a ,palaeozoic forest might easily be injured by some of the large amphibians1 which were the highest representatives of animal life during the ,carboniferous period1 just as our forest trees are often barked by deer1 rabbits1 and other animals4 ,fissures might also be formed by the expansion of the bark under the heating influence of the sun's rays#fah4 ,such a specimen as that of fig4 #hj gives an air of living reality to the petrified fragments of the ,coal period trees4 ,it is well known how a wound on the branch of a forest tree becomes gradually overgrown by the activity of the cambium giving rise to a thick callus1 which gradually closes over the wounded surface in the form of two lips of wood which finally meet over the middle of the scar4 ,the two lips of callus are clearly shown in the fossil branch arching over the tear in the wood just beyond the ring of carinal canals4 ,the tissue external to the wood represents the imperfectly preserved cortex4 ,a section which was cut parallel to that of fig4 #hj shows a continuous band of wood beyond the wound1 and the latter has the form of a small triangular gap2 this section appears to have passed across the wound where it was narrower and has already been closed over by the callus4 ,the formation of a rather different kind of callus wood has been described by ,renault#fai and by ,williamson and ,scott#fbj1 in stems where aborted or deciduous branches have been overgrown and sealed up by cambial activity4 ,illustration3 ,,fig4 #hj4 ,diagrammatic sketch of a transverse section of a ,calamite twig1 showing callus wood4 ,from a specimen in the ,cambridge ,botanical ,laboratory ,collection4 ca4 #aj4 ,illustration3 ,,fig4 #ha4 ,calamites4 ,longitudinal section 7,r1 radial2 ,t1 tangential7 of a small branch4 b1 position of a lateral branch4 ,from a specimen 7no4 #aicg7 in the ,williamson ,collection4 ,slightly enlarged4 ,some of the features to be noticed in longitudinal sections of ,calamite stems have already been described1 at least as regards younger branches4 ,the specimen shown in fig4 #ha illustrates the general appearance of a stem as seen in tangential and radial section4 ,in the lower portion1 ,t1 the course of the vascular bundles is shown by the black lines which represent the xylem tracheids1 bifurcating and usually alternating at each node4 ,between the xylem strands are the broad principal medullary rays4 ,at b a branch has been cut through on its passage out from the parent stem1 just above the nodal line4 ,in tangential sections of ,calamite stems one frequently sees both branches and leaf-trace bundles 7fig4 #hc1 ,a71 passing horizontally through the wood and enclosed by strongly curved and twisted tracheids4 ,in the upper part of the figure 7#ha1 ,r71 the section has passed through the centre of the stem1 and the wood is seen in radial view2 each node is bridged across by a diaphragm of parenchymatous cells capable of giving rise to a surface layer of periderm#fba4 ,an outgoing branch1 as seen in a tangential section of a stem1 consists of a parenchymatous pith surrounded by a ring of vascular bundles1 in which the characteristic carinal canals have not yet been formed1 but if the section has cut the branch further from its base1 there may be seen a circle of irregular gaps marking the position of the carinal canals4 ,such gaps are often occupied by thin parenchyma1 and contain protoxylem elements4 ,the outgoing branches1 as seen in a tangential section of a ,calamite stem1 are seen to be connected with the wood of the parent stem by curved and sinuous tracheids1 which give to the stem-wood a curiously characteristic appearance#fbb1 as if the xylem elements had been pushed aside and contorted by the pressure of the outgoing member4 ,a tangential section through a ,pine stem#fbc in the region of a lateral branch presents precisely the same features as in ,calamites4 ,the branches are given off from the stem immediately above a node and usually between two outgoing leaf-trace bundles4 ,sidenote3 ,,rhizome ,,of ,,calamites4 ,specimens of pith-casts occasionally present the appearance of a curved and rapidly tapered ram's horn1 and the narrow end of such a cast is sometimes found in contact with the node of another cast4 ,this juxtaposition of casts is shown unusually well in fig4 #hb4 ,in some of the published restorations of ,calamites the plant is represented as having thick branches attached to the main stem by little more than a point4 ,williamson#fbd clearly explained this apparently unusual and indeed physically impossible method of branching1 by means of sections of petrified stems4 ,the branches seen in fig4 #hb are of course pith-casts1 and in the living plant the pith of each branch was surrounded by a mass of secondary wood developed from as many primary groups of xylem as there are grooves on the surface of the cast1 each of the grooves on an internode corresponding to the projecting edge of a xylem group4 ,at the junction of one branch with another the pith was much narrower and the enclosing wood thicker1 so that the tapered ends of the cast merely show the continuity by a narrow union between the pith-cavities of different branches4 ,most probably the casts of fig4 #hb are those of a branched rhizome which grew underground1 giving off aerial shoots and adventitious roots4 ,there is a fairly close resemblance between the ,calamite casts of fig4 #hb and a stout branching rhizome of a ,bamboo1 e4g4 ,bambusa arundinacea ,willd42 it is not surprising that the earlier writers looked upon the ,calamite as a reed-like plant4 ,before leaving the consideration of stem structures there is another feature to which attention must be drawn4 ,on the casts shown in fig4 #hb there is a circle of small oval scars situated just below the nodes1 these are clearly shown at c1 c1 c4 ,each of the scars is in reality a slight projection from the upper end of an internodal ridge4 ,as the ridges correspond to the broad inner faces of medullary rays1 the small projection at the upper end of each ridge is a cast of a depression or canal which existed in the medullary tissue of the living plant4 ,there have been various suggestions as to the meaning of these oval projections2 several writers have referred to them as the points of attachments of roots or other appendages1 but ,williamson proved them to be the casts of canal-like gaps which traversed the upper ends of principal medullary rays in a horizontal direction4 ,in a tangential section of a ,calamite stem the summit of each primary medullary ray often contains a group of smaller elements which are in process of disorganisation1 and in some cases these cells give place to an oval and somewhat irregular canal4 ,in the diagrammatic tangential section represented in fig4 #hc1 ,a the upper end of each ray is perforated by a large oval space1 which has been formed as the result of the breaking down of a horizontal band of cells4 ,williamson designated these spaces infranodal canals4 ,while proving that they had nothing to do with the attachment of lateral members1 he suggested that they might be concerned with secretion2 but their physiological significance is still a matter of speculation4 ,the casts of infranodal canals are especially large and conspicuous in the subgenus ,arthrodendron1 a form of ,calamite characterised by certain histological features to be referred to later4 ,williamson#fbe originally regarded the presence of infranodal canals as one of the distinguishing features of ,arthrodendron1 but they occur also in the casts of the commoner type ,arthropitys4 ,as a rule we have only the cast of the inner ends of the infranodal canals preserved as slight projections like those in fig4 #hc1 ,a2 but in one exceptionally interesting pith-cast described by ,williamson1 these casts of the infranodal canals have been preserved as slender spoke-like columns radiating from the upper ends of the ridges of the infranodal region of a pith-cast4 ,illustration3 ,,fig4 #hb4 ,branched rhizome of ,calamites4 nat4 size4 ,c1 ,c1 nodes showing casts of infranodal canals4 ,from a specimen in the ,manchester ,museum1 ,owens ,college4 ,this specimen1 which was figured by ,williamson#fbf in two of his papers1 and by ,lyell#fbg in the fifth edition of his ,elementary ,geology1 is historically interesting as being one of the first important plants obtained by ,williamson early in the fifties1 when he began his researches into the structure of ,carboniferous plants4 ,a joiner1 who was employed by ,williamson to make a piece of machinery for grinding fossils1 brought a number of sandstone fragments as an offering to his employer1 whom he found to be interested in stones4 ,the specimens 8were in the main the merest rubbish1 but amongst them10 writes ,williamson1 8,i detected a fragment which was equally elegant and remarkable4444 ,in later days1 when the specimen so oddly and accidentally obtained1 came to be intelligently studied1 its history became clear enough1 and the priceless fragment is now one of the most precious gems in my cabinet#fbh40 ,comparison of three types of structure met with in ,calamitean stems1--,arthropitys1 ,arthrodendron1 and ,calamodendron4 ,sidenote3 ,,arthropitys4 ,the anatomical features which have so far been described as characteristic of ,calamites represent the common type met with in the ,english ,coal-,measures4 ,the same type occurs also in ,france1 ,germany and elsewhere4 ,it is that form of stem known as ,arthropitys1 a sub-genus of ,calamites4 ,arthropitys may be briefly diagnosed as follows1--confining our attention to the structure of the stem3 ,a ring of collateral bundles surrounds a large hollow pith1 each primary xylem strand terminates internally in a more or less bluntly rounded apex traversed by a longitudinally carinal canal4 ,the principal medullary rays consist of large-celled parenchyma1 of which the individual elements are usually tangentially elongated as seen in transverse section1 and four or five times longer than broad as seen in a tangential longitudinal section4 ,the secondary xylem consists of scalariform and reticulately pitted tracheids2 the interfascicular xylem may be formed completely across each primary ray at an early stage in the growth of the stem#fbi1 or it may be developed more gradually so as to leave a tapering principal ray of parenchyma between each primary xylem bundle4 ,in the latter case the principal rays present the characteristic appearance shown in figs4 #ga1 #gd1 ,a1 #ge and #gh1 a type of stem which we may refer to as ,calamites 7,arthropitys7 communis4 ,in the former case the stem presents the appearance shown in fig4 #hc1 ,d#fcj4 ,a third variety of ,arthropitys stem is one which was originally named by ,gppert ,arthropitys bistriata2 in this form the principal rays retain their individuality as bands of parenchyma throughout the whole thickness of the wood#fca4 ,such stems as those of figs4 #gc and #gd1 ,b1 may be young examples of ,arthropitys communis or possibly of ,a4 bistriata4 ,the narrow secondary medullary rays of ,arthropitys usually consist of a single row of cells which are three to five times higher than broad1 as seen in tangential longitudinal section4 ,infranodal canals occur in some examples of ,arthropitys4 ,sidenote3 ,,arthrodendron4 ,in the subgenus ,arthrodendron1 a type of stem first recognised by ,williamson and named by him ,calamopitys#fcb1 the principal medullary rays consist of prosenchymatous cells 7i4e4 elongated pointed elements7 and not parenchyma4 ,these elongated elements are not pitted like tracheids1 and they are shorter and broader than the xylem elements4 ,in some examples of this subgenus the primary rays are bridged across at an early stage by the formation of secondary interfascicular xylem1 and in others they persist as bands of ray tissue1 as in ,arthropitys4 ,other characteristics of ,arthrodendron are the abundance of reticulated instead of scalariform tracheids in the secondary wood1 and the large size of the infranodal canals4 ,fig4 #hc1 ,d represents part of a transverse section of ,arthrodendron2 in this stem the rays have been occupied by interfascicular xylem at a very early stage of the secondary growth4 ,the section from which fig4 #hc1 ,d is drawn was described by ,williamson in #ahga2 the complete section shows about #hj carinal canals and primary xylem groups4 ,the prosenchymatous form of the principal medullary rays is seen in fig #hc1 ,c1 and the reticulate pitting on the radial wall of a tracheid is shown in fig4 #hc1 ,b4 ,fig4 #hc1 ,a illustrates the large infranodal canals as seen in a tangential section of a stem4 ,the same section shows also the course of the vascular bundles characteristic of ,calamites as of ,equisetum1 and the position of outgoing leaf-traces is represented by unshaded areas in the black vascular strands4 ,illustration3 ,,fig4 #hc4 ,calamites 7,arthrodendron74 ,a4 ,tangential section 7diagrammatic7 showing the course of the vascular strands1 also leaf-traces and infranodal canals4 ,b4 ,radial face of a tracheid4 ,c4 ,prosenchymatous elements of a principal medullary ray4 ,d4 ,transverse section of the wood4 7,after ,williamson47 ,no4 #cf in the ,williamson ,collection4 ,the subgenus ,arthrodendron is very rarely met with1 and our information as to this type is far from complete#fcc4 ,the third subgenus ,calamodendron has not been discovered in ,english rocks1 and our knowledge of this type is derived from ,french and ,german silicified specimens#fcd4 ,there is the same large hollow pith surrounded by a ring of collateral bundles with carinal canals1 as in the two preceding subgenera4 ,the tracheids are scalariform and reticulate1 and the secondary medullary rays consist of rows of parenchymatous cells which are longer than broad1 as in ,arthropitys and ,arthrodendron4 ,illustration3 ,,fig4 #hd4 ,calamites 7,calamodendron7 intermedium1 ,ren4 ,transverse section through two vascular bundles4 a1 a1 xylem tracheids1 b1 b1 bands of prosenchyma1 c1 medullary ray4 7,after ,renault47 ,the most characteristic feature of ,calamodendron is the occurrence of several rows of radially disposed thick-walled prosenchymatous elements 7fig4 #hd1 b7 on either flank of each wedge-shaped group of xylem4 ,each principal ray is thus nearly filled up by bands of fibrous cells on the sides of adjacent xylem groups1 but the centre of each principal ray is occupied by a narrow band of parenchyma 7fig4 #hd1 c74 ,the relative breadth of the xylem and prosenchymatous bands has been made use of by ,renault as a specific character in ,calamodendron stems4 ,fig4 #hd is copied from a drawing recently published by this ,french author of a new species of ,calamodendron1 ,c4 intermedium#fce4 ,in this case the bands of fibrous cells1 b1 are slightly broader1 as seen in a transverse section of the stem1 than the bands of xylem tracheids1 a4 ,the narrow band1 c1 consists of four rows of the parenchymatous tissue of a medullary ray4 ,at the inner end of each group of tracheids there is a large carinal canal4 ,the question of the recognition of the pith-casts of stems possessing the structure of any of the three subgenera of ,calamites is referred to in a later section of this chapter4 b4 ,leaves ,leaves of ,calamites and ,calamitean foliage-shoots1 including an account of 77 ,calamocladus 7,asterophyllites7 and 77 ,annularia4 ,our knowledge of the structure and manner of occurrence of ,calamite leaves is very incomplete4 ,there are numerous foliage-shoots among the fossils of the ,coal-,measures which are no doubt ,calamitean1 but as they are nearly always found apart from the main branches and stems1 it is generally impossible to do more than speak of them as probably the leaf-bearing branches of a ,calamite4 ,the familiar fossils known as ,asterophyllites1 and in recent years often referred to the genus ,calamocladus1 are no doubt ,calamitean shoots2 but they are usually found as isolated fragments1 and it is seldom that we are able to refer them to definite forms of ,calamites4 ,another common ,coal-,measure genus1 ,annularia1 is also ,calamitean1 and at least some of the species are no doubt leafy shoots of ,calamites4 ,although it is generally accepted that the fossils referred to as ,asterophyllites or ,calamocladus are portions of ,calamites1 and not distinct plants1 it is convenient1 and indeed necessary1 to retain such a term as ,calamocladus as a means of recording foliage-shoots1 which may possess both a botanical and a geological value4 ,some of the ,calamite casts1 especially those referred to the subgenus ,calamitina1 are occasionally found with leaves attached to the nodes4 ,in some stems the leaves are arranged in a close verticil1 and each leaf has a narrow linear form and is traversed by a single median vein4 ,figures of ,calamite stems with verticils of long and narrow leaves may be found in ,lindley and ,hutton#fcf1 and in the writings of many other authors#fcg4 ,in the specimen shown in fig4 #he the leaves are preserved apart from the stem1 but from their close association with a ,calamite cast1 and from the proofs afforded by other specimens1 it is quite certain they formed part of a whorl of leaves attached to the node of a true ,calamite1 and a stem having that particular type known as ,calamitina#fch 7figs4 #ii1 #ajj74 ,it is probable that in some ,calamites1 and especially in younger shoots1 the leaves had the form of narrow sheaths split up into linear segments4 ,this question has already been referred to in dealing with certain ,palaeozoic fossils referred to ,equisetites#fci4 ,illustration3 ,,fig4 #he4 ,linear leaves of a ,calamite 7,calamitina74 ,after ,weiss1 slightly reduced4 ,a few years ago the late ,thomas ,hick#fdj1 of ,manchester1 described the structure of some leaves which he believed to be those of a ,calamite4 ,he found them attached to a slender axis which possessed the characteristics of a young ,calamite branch4 ,there can be little doubt that his specimens are true ,calamite leaves4 ,the sketches of fig4 #hf have been made from the sections originally described by ,hick4 ,fig4 #hf1 #a shows a leaf in transverse section2 on the outside there is a well-defined epidermal layer with a limiting cuticle4 ,internal to this we have radially elongated parenchymatous cells forming a loose or spongy tissue1 the cells being often separated by fairly large spaces 7fig4 #hf1 #e71 especially in the region of the blunt lateral wings of the leaf4 ,some of these cells contain a single dark dot1 which in all probability is the mineralised nucleus4 ,these pallisade-like cells probably contained chlorophyll and constituted the assimilating tissue of the leaf4 ,in the centre there is a circular strand of cells limited by a layer of larger cells with black contents1 enclosing an inner group of small-celled parenchyma and traversed by a few spiral or scalariform tracheids constituting the single median vein4 ,it is hardly possible to recognise any phloem elements in the small vascular bundle2 there appear to be a few narrow tracheids surrounded by larger parenchymatous elements 7fig4 #hf1 #b74 ,at one point in the epidermis of fig4 #hf1 #a1 there appears to be a stoma1 but the details are not very clearly shown 7fig4 #hf1 #d72 the two cells1 s1 s1 bordering the small aperture are probably guard-cells4 ,illustration3 ,,fig4 #hf4 ,a leaf of ,calamites4 #a4 ,transverse section2 t1 vascular bundle2 x1 sheath of cells4 #ce4 #b4 ,vascular bundle consisting of a few small tracheids1 t4 #c4 ,a tracheid and a few parenchymatous cells1 the latter with nuclei4 #d4 ,a stoma2 s1 s1 guard-cells4 #e4 ,pallisade cells and intercellular spaces4 ,from a section in the ,manchester ,museum1 ,owens ,college4 ,the nature of the assimilating tissue1 the comparatively thick band of thin-walled cells with intercellular spaces1 and the exposed position of the stomata suggest that the plant lived in a fairly damp climate2 at least there is nothing to indicate any adaptation to a dry climate4 ,in the ,binney collection of plants in the ,woodwardian ,museum1 ,cambridge1 there is a species of a very small shoot bearing three or four verticils of leaves which possess the same structure as those of fig4 #hf4 ,we may probably regard such twigs as the slender terminal branches of ,calamitean shoots4 4 ,calamocladus 7,asterophyllites74 ,the generic name ,asterophyllites was proposed by ,brongniart#fda in #ahbb for a fossil previously named by ,schlotheim#fdb ,casuarinites1 and afterwards transferred to ,sternberg's genus ,annularia4 ,in #ahbh ,brongniart#fdc gave the following diagnosis of the fossils which he included under the genus ,asterophyllites3--8,stems rarely simple1 usually branched1 with opposite branches1 which are always disposed in the same plane2 leaves flat1 more or less linear1 pointed1 traversed by a simple median vein1 free to the base40 ,lindley and ,hutton described examples of ,brongniart's genus as species of ,hippurites#fdd1 and other authors adopted different names for specimens afterwards referred to ,asterophyllites4 ,at a later date ,ettingshausen#fde and other writers expressed the view that the fossils which ,brongniart regarded as a distinct genus were the foliage-shoots of ,calamites1 and ,ettingshausen went so far as to include them in that genus4 ,in view of the generally expressed opinion as to the ,calamitean nature of ,asterophyllites1 ,schimper#fdf proposed the convenient generic name ,calamocladus for 8rami et ramuli foliosi0 of ,calamites4 ,some recent authors have adopted this genus1 but others prefer to retain ,asterophyllites4 ,in a recent important monograph by ,grand',eury#fdg ,calamitean foliage-shoots are included under the two names1 ,asterophyllites and ,calamocladus2 the latter type of foliage-shoots he associates with the stems of the subgenus ,calamodendron1 and the former he connects with those ,calamitean stems which belong to the subgenus ,arthropitys4 ,it is an almost hopeless task to attempt to connect the various forms of foliage-shoots with their respective stems1 and to determine what particular anatomical features characterised the plants bearing these various forms of shoots4 ,we may adopt ,schimper's generic name ,calamocladus in the same sense as ,asterophyllites1 but as including such other foliage-shoots as we have reason to believe belonged to ,calamites4 ,those leaf-bearing branches which conform to the type known as ,annularia are however not included in ,calamocladus1 as we cannot definitely assert that these foliage-shoots belong in all cases to ,calamitean stems4 ,grand',eury's use of ,calamocladus in a more restricted sense is inadvisable as leading to confusion1 seeing that this name was originally defined in a more comprehensive manner as including ,calamitean leaf-bearing branches generally4 ,we may define ,calamocladus as follows3-- ,branched or simple articulated branches bearing whorls of uni-nerved linear leaves at the nodes2 the leaves may be either free to the base or fused basally into a cup-like sheath 7e4g4 ,grand',eury's ,calamocladus74 ,the several acicular linear leaves or segments which are given off from the nodes spread out radially in an open manner in all directions2 they may be either almost at right angles to the axis or inclined at different angles4 ,each segment is traversed by a single vein and terminates in an acuminate apex4 ,as a typical example of a ,calamitean foliage-shoot the species ,calamocladus equisetiformis 7,schloth47 may be briefly described4 ,the synonymy of the commoner species of fossil plants is a constant source of confusion and difficulty2 in order to illustrate the necessity of careful comparison of specimens and published illustrations1 it may be helpful to quote a few synonyms of the species more particularly dealt with4 ,the exhaustive lists drawn up by ,kidston in his ,catalogue of ,palaeozoic plants in the ,british ,museum will be found extremely useful by those concerned with a systematic study of the older plants4 ,illustration3 ,,fig4 #hg4 ,calamocladus equisetiformis 7,schloth474 ,from a specimen in the ,british ,museum 7,mc,murtrie ,collection1 no4 ,v4 #bifc74 ca4 nat4 size4 ,calamocladus equisetiformis 7,schloth474 ,fig4 #hg4 #ahji4 ,phytolithus1 ,martin#fdh4 #ahbj4 ,casuarinites equisetiformis1 ,schlotheim#fdi4 #ahbe4 ,bornia equisetiformis1 ,sternberg#fej4 #ahbh4 ,asterophyllites equisetiformis1 ,brongniart#fea4 #ahcf4 ,hippurites longifolia1 ,lindley and ,hutton#feb4 #ahee4 ,calamites equisetiformis1 ,ettingshausen#fec4 #ahfi4 ,calamocladus equisetiformis1 ,schimper#fed4 #ahfi4 ,annularia calamitoides1 ,schimper#fed4 ,the above synonyms do not exhaust the list#fee1 but they suffice to illustrate the necessity of a careful comparison in drawing up tables of species1 in connection with geographical distribution or for other purposes4 ,calamocladus equisetiformis may be briefly defined as follows3--,a central axis possessing a hollow pith of ,calamitean character1 divided externally into well-marked slightly constricted nodes and internodes2 from the nodes long narrow and free leaves are borne in whorls2 from the axils of some of the leaves lateral branches are given off inclined at a fairly wide angle to the main axis1 and bearing crowded verticils of spreading acicular leaves4 ,the unusually good specimen1 #che cm4 long1 shown on a much reduced scale in fig4 #hg1 illustrates the characteristic habit of this form of ,calamocladus4 ,it is from the ,radstock coal-field of ,somersetshire1 one of the best ,english localities for ,coal-,measure plants4 ,an exceedingly good collection of ,radstock plants has recently been presented to the ,british ,museum by ,mr ,j4 ,mc,murtrie2 it includes many fine specimens of ,calamites4 ,a small example--probably of this species--from ,coalbrook ,dale1 near ,dudley1 in ,shropshire1 and now in the ,british ,museum1 illustrates very well the appearance of a young and partially expanded ,calamitean foliage-shoot4 ,the central axis1 #fe cm4 in length1 includes about #ae internodes1 and terminates in a bud covered by several small leaves4 ,lateral branches are given off at a wide angle1 and small unexpanded buds occur in the axils of several of the leaves4 ,as an example of the leaf-bearing branches which ,grand',eury has recently described as ,calamocladus1 using the genus in a more restricted sense than is adopted in the present chapter1 reference may be made to the fragment shown in fig4 #fh1 ,a4 ,the foliage-shoots of this type bore verticils of linear leaves1 coherent basally in the form of a cup1 at the ends of branches and not in a succession of whorls on each branch4 ,the association of reproductive organs1 in the form of long and narrow strobili1 with ,calamocladus is referred to in the sequel4 ,the specimens described by ,grand',eury are in the cole des ,mines ,museum1 ,paris2 some of the shoots which are well preserved bear a resemblance in habit of growth to the genus ,archaeocalamites4 4 ,annularia4 ,in #ahbj this generic name was applied by ,sternberg#fef to some specimens of branches bearing verticils of linear leaves4 ,in #ahbh ,brongniart#feg thus defined the genus ,annularia3--8,slender stem1 articulated1 with opposite branches arising above the leaves4 ,leaves verticillate1 flat1 frequently obtuse1 traversed by a single vein1 fused basally and of unequal length40 ,in the works of earlier writers we find frequent illustrations of specimens of ,annularia1 which are compared with ,asters and other recent flowering plants4 ,lehmann#feh contributed a paper to the ,royal ,academy of ,berlin in #agef1 in which he referred to certain fossil plants as probable examples of flowers1 among them being a specimen of ,annularia4 ,he refers to the occurrence of fossil ferns and other plants1 and asks why we do not find flowers of the rose or tulip2 his object being 8not to acquire vain glory1 but to give occasion for others to look into the matter more clearly40 ,the general habit of the fossils which are now included under ,annularia agrees closely with that of ,calamocladus4 ,there is the same spreading form and a similar foliage in the two genera1 but in ,annularia the members of a whorl are always fused into a basal sheath1 and the segments are not of equal length4 ,we may thus summarise the characteristic features of the genus3-- ,opposite branches are given off in one plane from the nodes of a main axis2 the leaves are in the form of narrow sheaths divided into numerous and unequal linear or narrow lanceolate segments1 each with a median vein4 ,the segments in each whorl appear to be spread out in one plane very oblique to the axis of a branch1 instead of spreading radially in all directions2 the lateral segments are usually longer than the upper and lower members of a whorl4 ,the vegetative branches possess the same type of structure as ,calamites4 ,a comparison of ,annularia and ,phyllotheca has already been made in ,chapter ,,ix4 7p4 #bhb74 ,potoni#fei has recently given a detailed account of ,annularian leaves2 he compares them with those of ,equisetum1 and describes the occurrence on the lamina of each leaf-segment of a broad central band or midrib1 with a groove1 probably containing stomata1 on either side4 ,he shows that in well-preserved specimens of ,annularia1 it is possible to recognise certain minute surface-features1 such as the presence of hairs and stomata1 which enable one to detect a close resemblance between the leaves of ,calamite stems and those of ,annularian shoots4 ,it is not always easy to distinguish between ,annularia and ,calamocladus2 the collar-like basal sheath in the leaves of the former is a characteristic feature1 but that cannot always be recognised4 ,on the other hand1 the leaves of ,calamocladus may sometimes be flattened out on the surface of the rock and simulate the deeply cut sheaths of ,annularia4 ,it is difficult to decide how far the manner of occurrence of ,annularian leaves in one plane1 which is commonly insisted on as a generic character1 is an original feature1 or how far it is the result of compression in fossilisation4 ,probably the leaves of a living ,annularia were spread out at right angles to the axis1 as in the #8verticils' of such a plant as ,galium4 ,dawson#ffj has described some fossils from the ,devonian rocks of ,canada as species of ,asterophyllites2 the figures bear a closer resemblance to the genus ,annularia4 ,the same author figures some irregularly whorled impressions as ,protannularia1 which appear to be identical with a fossil described by ,nicholson#ffa from the ,skiddaw slates 7,ordovician7 of ,cumberland as ,buthotrephis radiata1 but the specimens are too imperfect to admit of accurate determination4 ,annularia stellata 7,schloth474 ,fig4 #hh4 #ahbj4 ,casuarinites stellatus1 ,schlotheim#ffb4 #ahbf4 ,bornia stellata1 ,sternberg#ffc4 #ahbh4 ,annularia longifolia1 ,brongniart#ffd4 #ahcd4 ,asterophyllites equisetiformis1 ,lindley and ,hutton#ffe4 #ahfh4 ,asterophyllites longifolius1 ,binney#fff4 #ahhg4 ,annularia ,geinitzi1 ,stur#ffg4 #ahhg4 ,annularia westphalica1 ,stur4 ,this species was figured by ,scheuchzer#ffh in his ,herbarium ,diluvianum1 and compared by him with a species of ,galium 7,bedstraw74 ,brongniart first made use of the generic name ,annularia for this common ,coal-,measure species1 which may be defined as follows3-- ,stem reaching a diameter of about #f-h cm41 with internodes #f-ab cm4 in length1 the surface either smooth or faintly ribbed4 ,primary branches given off in opposite pairs from the nodes1 the lateral branches giving off smaller branches disposed in the same manner4 ,the smaller branches bear verticils of leaves at each node2 both leaves and ultimate branches being in one plane4 ,the leaves are narrow1 lanceolate-spathulate in form1 broadest about the middle1 #a-e cm4 in length and #a-c mm4 broad1 hairy on the upper surface#ffi2 each leaf is traversed by a single vein4 ,illustration3 ,,fig4 #hh4 ,branch of ,annularia stellata 7,schloth474 nat4 size4 ,from a specimen in the ,collection of ,mr ,r4 ,kidston4 ,upper ,coal-,measures1 ,radstock4 ,each whorl contains #af-cb segments1 which are connected basally into a collar or narrow sheath2 the lateral segments are usually longer than the upper and lower4 ,the branches are about #f-bj mm4 broad1 with finely ribbed internodes #c-g cm4 long1 bearing verticils of leaves2 the ultimate branches arise in pairs in the axils of the lateral segments of the verticils4 ,the strobili are of the ,calamostachys#fgj type and are borne on the main branches or possibly on the stem2 they have a long and narrow form and are attached in verticils at the nodes4 ,each strobilus consists of a central axis bearing alternate whorls of linear lanceolate sterile bracts and sporangiophores1 about half as numerous as the sterile bracts2 each sporangiophore bears four ovoid sporangia4 ,the anatomical structure of a specimen referred to ,annularia stellata has been described by ,renault#fga4 ,the cortex consists of parenchyma traversed by lacunae and limited peripherally by a denser hypodermal tissue4 ,in the stele ,renault describes #ad xylem strands1 each with a large carinal canal4 ,the pith was apparently large and hollow4 ,the same author describes an ,annularia strobilus in which the lower sporangiophores bear macrosporangia1 and the upper microsporangia4 ,illustration3 ,,fig4 #hi4 ,annularia sphenophylloides 7,zenk474 ,a4 ,strobilus 7,stachannularia calathifera1 ,weiss74 nat4 size4 ,b4 ,vegetative shoot4 nat4 size4 ,from specimens in the ,collection of ,mr ,r4 ,kidston4 ,upper ,coal-,measures1 ,radstock4 ,the references in the footnote should be consulted for figures of this species of ,annularia2 it is from the examination of such specimens as are referred to in the note that the above diagnosis has been compiled#fgb4 ,annularia sphenophylloides 7,zenk474 ,fig4 #hi4 #ahcc4 ,galium sphenophylloides1 ,zenker#fgc4 #ahfe4 ,annularia brevifolia1 ,heer#fgd1 ,strobilus4 #ahgf4 ,calamostachys 7,stachannularia7 calathifera1 ,weiss#fge4 ,principal branches #h-ab mm4 wide1 with internodes #h-aj cm4 in length1 giving off two opposite branches at the nodes2 from the secondary branches arise smaller branches in opposite pairs4 ,the leaf-verticils and branches are all in one plane4 ,each verticil consists of #ab-ah spathulate segments1 #c-aj mm4 long1 cuneiform at the base and broader above1 with an acuminate tip2 the lateral segments are slightly longer than the upper and lower members of a whorl4 ,the small and crowded leaf-whorls give to this species a characteristic appearance1 which readily distinguishes it from the larger-leaved forms such as ,annularia stellata4 ,a fossil figured by ,lhwyd#fgf in #afii as ,rubeola mineralis is no doubt an example of ,annularia sphenophylloides4 ,annularian branches are occasionally found with cones given off from the axils of some of the leaf-whorls4 ,an interesting specimen1 which is now in the ,leipzig ,museum1 was described by ,sterzel in #ahhbfgg1 showing cones attached to a vegetative shoot of ,annularia sphenophylloides4 ,the long and narrow strobili--#be cm4 long and about #f mm4 broad--appear very large in proportion to the size of the vegetative branches4 ,a fertile shoot consists of a central axis bearing whorls of bracts alternating with sporangiophores1 to each of which are attached four sporangia4 ,the specimen in fig4 #hi1 ,a1 does not show the details clearly2 each transverse constriction represents the attachment of a whorl of linear bracts2 the whole cone appears to consist of a series of short broad segments4 ,the divisions in the lower half of each segment mark the position of the sterile bracts1 while those of the upper half represent the outlines of the upper sporangia of each whorl of sporangiophores1 the lower sporangia being hidden by the ring of linear bracts#fgh4 ,on some portions of the specimen of fig4 #hi1 ,a1 it is possible to recognise the outlines of cells on the coaly surface-film2 these probably belong to the sporangium wall4 ,this type of cone is included under the genus ,calamostachys1 a name applied to ,calamitean strobili with certain morphological characters1 as described on p4 #cea4 c4 ,roots4 ,in #ahga ,williamson#fgi described some sections of what he considered to be a distinct variety of a ,calamite stem4 ,the chief peculiarity which he noticed lay in the absence of carinal canals1 and in the solid pith4 ,some years later the same observer#fhj came to the conclusion that the specimens were probably those of a plant generically distinct from ,calamites2 he accordingly proposed a new name ,astromyelon4 ,subsequently ,cash and ,hick#fha gave an account of some examples of apparently another form of plant1 to which they gave the name ,myriophylloides ,williamsonis2 and ,williamson#fhb suggested the term ,helophyton as a more suitable generic designation4 ,it was1 however1 demonstrated by ,spencer#fhc that the plant described by ,cash and ,hick was identical with ,williamson's ,astromyelon4 ,williamson#fhd then gave an account of several specimens of this type illustrating various stages in the growth and development of the ,astromyelon #8stems1' which he compared with the rhizome of the recent genus ,marsilia4 ,in #ahhe ,renault#fhe published an account of ,astromyelon in which he brought forward good evidence in favour of regarding it as a ,calamitean root4 ,the same author has recently given some excellent figures and a detailed description of certain specific types of these ,calamite roots1 and ,williamson and ,scott's memoir on the roots of ,calamites has rendered our knowledge of ,astromyelon almost complete4 ,some of the finest specimens1 in which the organic connection between typical ,calamite stems and ,astromyelon roots is clearly demonstrated1 are in the ,natural ,history ,museum1 ,paris4 ,there are several sections also from ,english material which show the connection between root and stem very clearly4 ,illustration3 ,,fig4 #ij4 ,pith-cast of a ,calamite stem1 with roots2 embedded in sandstone and shale4 7,after ,grand',eury47 ,much reduced4 ,casts of the hollow pith of ,calamite rhizomes or aerial branches are occasionally found in which slender appendages are given off either singly or in tufts from the nodal regions4 ,many examples of such casts have been figured by ,lindley and ,hutton#fhf1 ,binney#fhg1 ,grand',eury#fhh1 ,weiss#fhi1 ,stur1 and other writers#fij4 ,the large stem-cast of fig4 #ij illustrates the manner of occurrence of long branched roots on the nodes of a ,calamite growing in sandy or clay soil4 ,the lower and more darkly shaded portion of the specimen is covered by a layer of coal representing the carbonised wood and cortex1 which has been moulded on to the sandstone pith-cast4 ,in fig4 #gg 7p4 #caf7 a fairly thick root is seen1 in organic connection with one of the nodes1 ,n #c1 and on ,n #b there is a scar of another root4 ,there are certain external characters by which one may often recognise a ,calamitean root4 ,there is no division into nodes and internodes as in stems1 and as the pith of the root was usually solid the parallel ribs and grooves of stem-casts are not present4 ,in smaller flattened roots there may sometimes be seen a central or excentric black line representing the stele1 and the surface of the root presents a curious wrinkled or shagreen texture1 probably due to the shrinkage of the loose lacunar cortex4 ,the occasional excentric position of the stele is no doubt due to the displacement of the vascular cylinder as a result of the rapid decay of the cortical tissues4 ,in the ,bergakademie of ,berlin there are some unusually good examples of ,calamite casts bearing well-preserved root-impressions2 these include the original specimens figured by ,weiss#fia4 ,no doubt some of the roots figured by various writers under the names ,pinnularia#fib and ,hydatica#fic belong to ,calamites1 but it is often impossible to identify detached specimens with any certainty4 ,the section figured diagrammatically in fig4 #ia ,a shows the characteristic single series of large lacunae1 l1 in the middle cortical region4 ,in the centre there is a wide solid pith surrounded by a ring of vascular tissue1 x4 ,the appearance of the middle cortex is very like that of the stem of a water-plant such as ,myriophyllum1 the ,water ,milfoil2 it shows that the ,calamite roots grew either in water or swampy ground4 ,in fig4 #ia ,b1 the root characters are clearly seen2 the centre of the stele is occupied by large parenchymatous cells which are rather longer than broad in longitudinal view2 at the periphery there are four protoxylem groups px1 alternating with four groups of phloem1 ph1 the latter being situated a little further from the centre of the stele4 ,the structure is therefore that of a typical tetrarch root4 ,in the example represented in the figure secondary thickening has begun1 and the cambial cells internal to each phloem group have given rise to a few radially disposed tracheids1 x4 ,beyond the phloem there are two layers of parenchyma representing1 as regards position1 a pericycle and an endodermis4 ,in the ordinary pericycle and endodermis of the roots of most plants the cells of the two layers are on alternate radii1 but in the ,calamite root1 as in ,equisetum roots1 the cells of these layers are placed on the same radii1 as seen in the neighbourhood of x in the figure4 ,this correspondence of the radial walls of the endodermal and pericyclic cells points to the development of both layers from one mother-layer1 and suggests the #8double endodermis' or phloeoterma of ,equisetum 7p4 #bed74 ,the cells in the outer of these two layers have slight thickenings on the radial walls recalling the usual character of endodermal cells4 ,the phloeoterma is succeeded by a few layers of parenchyma1 constituting the inner cortex1 and beyond this we have the large lacunae separated from one another by slender trabeculae of cells4 ,the outer cortex is limited by a well-defined layer of thick-walled cells1 which may be spoken of as the epidermoidal#fid layer4 ,roots possessing this superficial layer of thicker cells have no doubt lost the original surface-layer which produced the absorptive root-hairs4 ,illustration3 ,,fig4 #ia4 ,a4 ,diagrammatic sketch of a transverse section of a young root of ,calamites4 x1 xylem2 l1 lacuna4 ,after ,hick4 ,b4 ,central cylinder 7stele7 of root1 px1 protoxylem2 ph1 phloem2 x1 secondary xylem2 l1 phloeoterma4 #ge4 ,after ,williamson and ,scott4 ,the xylem elements have the form of spiral1 reticulate and scalariform tracheids4 ,in roots or rootlets smaller than that shown in fig4 #ia ,b1 the primary xylem may extend to the centre of the stele1 and form a continuous axial strand2 in such examples the structure may be diarch1 triarch or tetrarch4 ,the origin of the cambium agrees with that in recent roots1 the cells immediately external to the protoxylem tracheids become meristematic1 as also those internal to the phloem4 ,another root-character is seen in the endogenous origin of lateral members4 ,good examples of branching roots are figured by ,williamson#fie and by ,williamson and ,scott#fif4 ,older roots#fig are usually found in a decorticated condition4 ,a transverse section of root in which secondary thickening has been active for some time presents on a superficial view a close resemblance to a stem of ,calamites1 but a careful comparison at once reveals important points of difference4 ,the specimen diagrammatically sketched in fig4 #ib illustrates very clearly the origin of a root from the node of a ,calamite stem4 ,the section has passed through a stem in a tangential direction1 showing the characteristic arrangement of the vascular bundles x1 and principal medullary rays m4 ,the small leaf-traces1 t1 t1 afford another feature characteristic of a ,calamite stem4 ,the portion of stem to the right of the figure has been slightly displaced1 and between this piece and the root ,r1 one of the ubiquitous ,stigmarian appendages1 s1 has inserted itself4 ,at ,r a fairly thick and decorticated root is seen in oblique transverse section2 at the upper end the root tracheids are seen in direct continuity with the xylem of the stem4 ,in the centre of the root is the large solid pith surrounded by twelve bluntly pointed xylem groups1 composed in the main of radially disposed scalariform elements with narrow secondary medullary rays like those in a stem4 ,between each xylem group there is a broad medullary ray1 which tapers rapidly towards the outside1 and is soon obliterated by the formation of interfascicular secondary xylem4 ,at ,r a portion of another root is seen in transverse section1 and ,r the inner part of a single xylem group is shown more clearly4 ,the solid pith and the absence of carinal canals are the two most obvious distinguishing features of the roots4 ,illustration3 ,,fig4 #ib4 ,tangential section through a node of ,calamites1 showing a root in organic connection with the stem4 ,r1 ,r4 ,root 7,astromyelon7 in transverse and oblique section1 x1 xylem2 m1 primary medullary ray2 t1 leaf-trace2 s1 ,stigmarian appendage4 ,r1 the inner portion of one of the xylem wedges of ,r more highly magnified4 ,sketched from a section in the ,cambridge ,botanical ,laboratory ,collection4 ,as ,renault points out1 roots of ,calamites have been figured by some writers#fih as examples of stems1 but it is usually comparatively easy to distinguish between roots and stems4 ,on examining the xylem groups more closely1 one notices that the apex of each is occupied by a triangular group of centripetally-developed primary tracheids1 the narrow spiral protoxylem elements occupying the outwardly directed apex4 ,the protoxylem apex is usually followed externally by a ray of one or two radially disposed series of parenchymatous cells4 ,this ray is not distinguished in fig4 #ib ,r from the rows of xylem tracheids4 ,each xylem group is thus formed partly of centripetal xylem and in part of secondary centrifugal xylem2 the latter is associated with secondary medullary rays1 as in stems1 and contains a broader ray 7fascicular ray of ,williamson and ,scott#fii7 immediately opposite each protoxylem strand4 ,in the roots of recent plants 7e4g4 ,cucurbita1 ,phaseolus1 c47 a broad medullary ray is often found opposite the protoxylem1 and such an arrangement is a perfectly normal structure in roots#gjj4 ,renault has recently described several species of ,calamite roots which he designates by specific names1 some of them belonging to stems with the ,arthropitys structure1 and others to ,calamodendron4 ,some of the roots figured by the ,french author have an axial strand of xylem with #g-ae projecting angles of protoxylem#gja4 ,these he considers true roots1 but the larger specimens with a wide pith he prefers to regard as stolons4 ,in the latter he mentions the union of the primary centripetal with the secondary centrifugal wood as a distinguishing feature4 ,it has been shown1 however1 that each group of secondary xylem includes a median ray of parenchyma1 and that the whole structure is essentially that of a root1 and not that of a modified stem or stolon4 ,the organs described by ,renault as true roots are probably rootlets1 and as ,williamson and ,scott have demonstrated1 there is every gradation between the smaller specimens with a solid xylem axis and those with a large central pith4 ,it is interesting to note that ,renault's figures of ,calamodendron roots show the closest resemblance to those of the subgenus ,arthropitys4 d4 ,cones4 ,the occurrence of fossil plants in the form of isolated fragments is a constant source of difficulty1 and is well illustrated by the numerous examples of strobili which cannot be connected with their parent stems4 ,we are1 however1 usually able to recognise ,calamitean cones if the impressions or petrified specimens are fairly well preserved1 but it is seldom possible to correlate particular types of cones with the corresponding species of foliage-shoots or stems4 ,palaeobotanical literature contains numerous illustrations and descriptions of long and narrow strobili designated by different generic terms such as ,volkmannia1 ,brukmannia1 ,calamostachys1 ,macrostachya and others2 many of these have since been recognised as the cones of ,calamites1 while some species of ,volkmannia have been identified with ,sphenophyllum stems4 ,before further considering the general question of ,calamite cones1 a few examples may be described in detail as types of fructification which are known to have been borne by ,calamites4 ,the examples selected are species of the two provisional genera ,calamostachys and ,palaeostachya4 ,the usual form of a ,calamite cone is illustrated in fig4 #ic1 which represents a fertile shoot bearing a few narrow linear leaves of the ,calamocladus type2 in the axils of some of these are borne the long strobili4 ,illustration3 ,,fig4 #ic4 ,calamostachys sp4 ,a fertile ,calamitean shoot4 ,from a specimen in the ,geological ,survey ,museum1 ,jermyn ,street1 ,london4 ,from the ,upper ,coal-,measures of ,monmouthshire 7,no4 #eeci74 ,calamostachys ,binneyana 7,carr474 ,figs4 #id and #ie4 ,in #ahfg ,carruthers#gjb gave an account of the structural features of the species of cones named by him ,volkmannia ,ludwigi and ,v4 ,binneyi1 the generic term having been originally used by ,sternberg#gjc for some impressions of ,carboniferous strobili4 ,brongniart#gjd in #ahdi referred to the various forms of ,volkmannia as cones of ,asterophyllitean branches1 and the latter he regarded as the foliage-shoots of a ,calamite stem4 ,in #ahfh ,binney#gje published a description1 with several illustrations1 of the cones named by ,carruthers ,volkmannia ,binneyi1 and referred to them as the fructification of that type of ,calamite stem spoken of in a previous section of this chapter 7p4 #caa7 as ,calamites 7,arthropitys7 communis 7,binney74 ,this cone is now usually spoken of as ,calamostachys ,binneyana2 the specific name ,binneyana being suggested by ,schimper#gjf in #ahfi as more euphonious than that proposed by ,carruthers4 ,in recent years our knowledge of both ,c4 ,binneyana and ,c4 ,ludwigi has been considerably extended4 ,we shall confine our attention in the following account to the former species#gjg4 ,some excellent figures of the latter species may be found in ,weiss' ,memoir#gjh on ,calamarieae4 ,one of the largest examples of ,calamostachys ,binneyana so far recorded has a length of #c-d cm4 and a maximum diameter of about #ge mm4 ,the axis of the cone bears whorls of sterile leaves or bracts at equal distances2 the linear bracts of each whorl are coherent basally as a disc or plate of tissue attached at right angles to the central axis of the cone4 ,the periphery of each of these discs divides up into twelve linear segments1 which curve upwards in a direction more or less parallel to the strobilus axis1 and at right angles to the coherent portion of each whorl4 ,the manner of occurrence of the whorls is shown in fig4 #id1 which has been sketched from a large section in the ,williamson collection4 ,the segments of the successive sterile verticils alternate with one another1 so that in the surface-view of a cone the long and narrow free bracts appear spirally disposed4 ,midway between these alternating sterile verticils there is a series of fertile appendages1 also given off in regular whorls4 ,each fertile whorl consists of about half as many members as the segments of a sterile whorl1 and the members of the several fertile whorls are superposed and not alternate4 ,each member has the form of a stalk or sporangiophore given off at right angles from the cone axis2 this is expanded distally into a peltate disc bearing four sporangia attached to its inner face4 ,in fig4 #id we can only see the basal portions of the sporangiophores1 which are shown in the upper part of the sketch as pointed projections1 ,sp1 from the cone axis4 ,each sporangiophore is traversed by a vascular strand which sends off a branch to the base of a sporangium 7fig4 #ie1 ,a1 t74 ,illustration3 ,,fig4 #id4 ,calamostachys ,binneyana 7,carr47 in longitudinal 7radial and tangential7 section4 ,sp1 sporangiophores2 ,s1 sporangia4 7,from specimen no4 #ajbb in the ,williamson ,collection1 ,british ,museum47 ,the axis of the cone is occupied by a single stele1 usually triangular in section2 the stele consists of a solid pith of elongated cells surrounded by six vascular bundles1 two at each corner4 ,a somewhat irregular gap marks the position of the protoxylem of each strand1 and portions of spiral or annular tracheids may occasionally be seen in the cavity4 ,these cavities1 which may be spoken of as the carinal canals1 disappear at the nodes1 where there is a mass of short reticulately pitted tracheids1 as in a ,calamite stem4 ,vascular bundles pass upwards in an oblique direction from the central stele to supply the bracts1 each of which is traversed by a single strand of tracheids4 ,the coherent portion1 or disc1 of each sterile whorl consists of sclerenchymatous elements towards the upper surface1 and of parenchyma below4 ,the pedicel of the sporangiophores consists of fairly thick-walled cells traversed by a single vascular strand1 and the peltate distal portions are made up of parenchymatous cells arranged in a palisade-like form at right angles to the free surface of the sporangiophores4 ,the vascular strand of the pedicel forks into two halves just below the peltate head1 and these branches again bifurcate to send a branch to each sporangium4 ,the four sporangia of each sporangiophore are attached by a narrow band of tissue to the shield-shaped distal expansion 7fig4 #ie1 ,a74 ,in a tangential section of a cone1 such as the lower portion of fig4 #id and in fig4 #ie1 ,b1 the sporangiophores present the appearance of narrow stalks 7fig4 #ie1 ,b1 a7 in the middle of a cluster of sporangia1 and the latter appear more or less square in outline4 ,the wall of a sporangium is made of a single layer of cells 7fig4 #ie1 ,b7 which present a characteristic appearance in surface-view 7fig4 #ie1 ,c71 the thin walls being crossed at right angles by small vertical plates4 ,in the tangential section of the coherent sterile whorls 7fig4 #ie1 ,b1 b and b7 the vascular strands are occasionally seen in transverse section 7fig4 #ie1 ,b1 t71 as they pass outwards to the several free bracts4 ,illustration3 ,,fig4 #ie4 ,calamostachys ,binneyana 7,carr474 ,a4 ,a sporangiophore and one sporangium4 t1 vascular bundle4 #de4 ,b4 ,tangential section showing portions of two sterile discs1 b1 b2 a sporangiophore1 a1 with its four sporangia1 in two of which are seen the spores2 t1 vascular bundle4 #ce4 ,c4 ,surface-view of cells of a sporangium wall4 #acj4 ,d4 ,spores and remains of mother-cells4 #acj4 7,after ,williamson and ,scott47 ,the spores in ,calamostachys ,binneyana are all of the same size1 and no macrospores have ever been seen4 ,in well preserved specimens tetrads of spores may be seen1 still enclosed by the wall of the spore-mother-cell 7fig4 #ie1 ,a and ,d72 and the torn remnants of the mother-cell sometimes simulate in appearance the elaters of an ,equisetum spore4 ,in surface-view a spore often shows clearly the three-rayed marking1 which is a characteristic feature of daughter-cells formed in a tetrad from a mother-cell4 ,the spores of a tetrad are in some cases of unequal size1 some having developed more vigorously than others4 ,this unequal growth and nourishment of spores is clearly shown in fig4 #if1 which represents a sporangium of a heterosporous ,calamitean strobilus1 ,c4 ,casheana4 ,williamson and ,scott#gji have described striking examples of spores in different stages of abortion1 and these authors draw attention to the importance of the phenomenon from the point of view of the origin of a heterosporous form of cone4 ,the abortion of some of the members of a spore-tetrad and the consequent increased nutrition of the more favoured daughter-cells1 might well be the starting-point of a process1 which would ultimately lead to the production of well defined macrospores and microspores4 ,the young microsporangia and macrosporangia of recent ,vascular ,cryptogams such as ,selaginella1 ,salvinia and other heterosporous genera are identical in appearance#gaj2 it is not until the spore-producing tissue begins to differentiate into groups of spores1 that the sporangia assume the form of macrosporangia and microsporangia4 ,during the evolution of the various known types of pteridophytic plants heterospory gradually succeeded isospory1 and this no doubt occurred several times and in different phyla of the plant kingdom4 ,in the mature sporangia of some of the ,calamitean strobili we have in the inequality of the spores in one sporangium an indication of the steps by which heterospory arose2 and in the immature sporangia of some recent genera we are carried back to a stage still nearer the starting-point of the substitution of the heterosporous for the isosporous condition4 ,calamostachys ,casheana ,will4 ,fig4 #if4 ,to ,williamson#gaa again is largely due the information we possess as to the structure of this type of ,calamitean strobilus4 ,its special interest lies in the occurrence of macrospores and microspores in the same cone4 ,the strobilus axis agrees in structure with that of ,c4 ,binneyana1 but in ,c4 ,casheana a band of secondary xylem forms the peripheral portion of the triangular stele4 ,were any further proof needed of the now well-established fact that secondary growth in thickness is by no means unknown as an attribute of ,vascular ,cryptogams1 the co-existence in the same cone of a cambium layer producing secondary wood and bark1 and cryptogamic macrospores and microspores1 affords conclusive evidence#gab4 ,the dogma accepted by many writers for a considerable number of years that the power of secondary thickening is evidence against a cryptogamic affinity1 has been responsible for no little confusion in palaeobotanical nomenclature4 ,on the axis of ,calamostachys ,casheana there are borne alternate whorls of fertile and sterile appendages similar to those in the homosporous ,c4 ,binneyana1 but they are inclined more obliquely to the axis of the cone4 ,macrospores and microspores have been found in sporangia borne on the same sporangiophore4 ,illustration3 ,,fig4 #if4 ,calamostachys ,casheana ,will4 ,a sporangium with macrospores and abortive spores4 #fe4 7,after ,williamson and ,scott47 ,the spore-tetrads in the macrosporangia occasionally include aborted sister-cells like those noticed in ,c4 ,binneyana2 this phenomenon is well illustrated by the unequally nourished spores in the sporangium of fig4 #if1 but no such starved spores have been found in the microsporangia4 ,in this cone1 then1 heterospory has become firmly established1 but the occurrence of undersized spores in a macrospore-tetrad leads us back to the probable lines of development of heterospory1 which are seen in ,c4 ,binneyana at their starting-point4 ,in the two species of strobili which have been described1 ,calamostachys ,binneyana and ,c4 ,casheana1 the sporangiophores or sporophylls are given off at right angles to the axis1 and midway between the sterile whorls4 ,these are two of the most important distinguishing features of the ,calamitean cones included under the generic term ,calamostachys4 ,in another form of cone1 which also belongs to ,calamitean stems1 the sporangiophores arise in the axil of the sterile leaves1 and are inclined obliquely to the axis of the cone4 ,to this type the generic name ,palaeostachya has been applied by the late ,prof4 ,weiss#gac of ,berlin4 ,the portion of a cone shown in fig4 #ig shows the arrangement of the sterile and fertile appendages characteristic of ,palaeostachya4 ,illustration3 ,,fig4 #ig4 ,palaeostachya pedunculata ,will4 ,part of a cone1 #c4 7,after ,weiss47 ,it is practically impossible to distinguish between cones of the ,calamostachys and ,palaeostachya type in the case of imperfectly preserved impressions2 indeed we cannot assume that all long and narrow cones with spirally disposed verticillate bracts are ,calamitean4 ,we must have the additional evidence of internal structure or of the direct association of the cones with ,calamitean foliage4 ,palaeostachya vera sp4 nov4 ,fig4 #ih4 ,in #ahfi ,williamson#gad described a fragment of a strobilus which showed certain anatomical features indicative of a close relationship or even identity with ,calamites4 ,some years later#gae a much more perfect example was obtained from the ,coal-,measures of ,lancashire1 and the additional evidence which it afforded definitely confirmed the earlier views of ,williamson4 ,the cone was more fully described by ,williamson in #ahhh1 as 8the true fruit of ,calamites40 ,it is clearly a form of ,weiss' genus ,palaeostachya2 ,williamson and ,scott#gaf refer to it in their ,memoir as ,calamites pedunculatus4 ,it is preferable1 however1 to retain the generic designation ,palaeostachya for cones of this type4 ,as the name ,p4 pedunculata has previously been adopted by ,weiss#gag for a cone figured by ,williamson#gah in #ahgd1 and afterwards referred to by that author in writing as ,p4 pedunculata1 it is proposed to substitute the specific name vera2 this specific name being chosen with a view to put on record the fact that it was this type of cone that ,williamson first proved to be the true fructification of the ,calamite4 ,the axis of ,p4 vera is practically identical in structure with a ,calamitean twig4 ,there is a hollow pith in the centre of the stele surrounded by a ring of #af-bj collateral bundles1 each of which is accompanied by a carinal canal as in a vegetative shoot4 ,as the pedicel of the strobilus passes into the cone proper it undergoes some modification in structure1 but retains the characteristic features of a ,calamite4 ,the diagrammatic longitudinal section of fig4 #ih1 which is copied from a drawing by ,williamson#gai1 shows the broadening of the vascular strands at the nodes1 and here and there a carinal canal is seen internal to the wood4 ,the axis of the cone bears whorls of bracts at right angles to the central column4 ,each whorl consists of about #cj-dj segments coherent basally into a disc of prosenchymatous and parenchymatous tissue4 ,the free linear bracts curve sharply upwards from the periphery of the disc1 approximately parallel to the axis of the cone4 ,from each of these sterile whorls there are given off #af-bj long and slender obliquely-inclined sporangiophores1 sp1 which arise from the upper surface of the disc close to the axis4 ,each sporangiophore no doubt bore four sporangia1 ,s1 containing spores of one size1--about #jge mm4 in diameter4 ,the specimens of ,palaeostachya vera so far obtained do not show the actual manner of attachment of the sporangia1 but more complete examples of other species of ,palaeostachya#gbj enable us to assume with certainty that the sporangiophores terminated in a distal peltate expansion bearing four sporangia on its inner face4 ,illustration3 ,,fig4 #ih4 ,diagrammatic longitudinal section of ,palaeostachya vera1 sp4 nov4 ,s1 ,s1 ,s1 sporangia2 x1 xylem2 sp1 sporangiophore4 7,after ,williamson47 ,a transverse section of the axis of the cone in the region of the sterile and fertile appendages shows the vascular bundles arranged in pairs4 ,in a section through the peduncle of the cone1 below the lowest whorl of bracts1 the bundles of the stele are situated at equal distances apart4 ,the cortical tissue of the peduncle is traversed by a ring of large canals#gba similar to the vallecular canals of an ,equisetum stem4 ,isospory is not a constant characteristic of ,palaeostachya2 some forms have been found with macrospores and microspores#gbb4 ,other ,calamitean cones1 and examples illustrating the connection between ,cones and ,vegetative ,shoots4 ,it would be out of place in an introduction to ,palaeobotany to attempt an exhaustive account of the various cones which were probably borne by ,calamitean plants1 but there are a few general points to which the attention of the student should be directed4 ,the examples dealt with in the foregoing description illustrate the fact1 that plants included under the comprehensive genus ,calamites bore cones possessing distinct morphological features4 ,there are1 however1 other types of strobili which have been found in organic connection with ,calamites2 and some of these must be taken into account in dealing with ,calamarian plants4 ,the genera ,volkmannia1 ,brukmannia1 ,huttonia1 ,macrostachya1 in addition to ,calamostachys and ,palaeostachya and others1 have been applied by different writers to ,calamitean cones4 ,as ,solms-,laubach#gbc has suggested1 it is wiser to discard ,volkmannia and ,brukmannia1 as they have been made to do duty for cones of widely different forms4 ,it is better to adhere to the provisional generic names used by ,weiss1 as they enable us to conveniently systematise the various ,calamarian strobili4 ,the following classification may be given of the better known cones1 some of which we are able to describe in considerable detail1 while others are still very imperfectly known4 ,we have good evidence that all these strobili were borne by vegetative shoots of the type of ,calamites1 ,calamocladus or ,annularia4 #a4 ,calamostachys#gbd 7including ,paracalamostachys and ,stachannularia74 ,cones long and narrow1 consisting of a central axis bearing alternate whorls of sterile and fertile appendages1 the latter having the form of sporangiophores attached at right angles to the axis midway between the sterile verticils1 and bearing four sporangia on the inner face of a peltate distal expansion4 ,calamostachys ,binneyana ,schimp41 ,c4 ,ludwigi ,carr41 ,c4 ,casheana ,will41 may be referred to as examples of this type of cone2 also some of the strobili described by different authors as species of ,volkmannia#gbe1 ,brukmannia#gbf1 c4 ,although one cannot make out the detailed structure of a ,calamite cone in the absence of internal structure1 it is often possible to recognise the essential features in specimens preserved in ironstone nodules1 such as those from ,coalbrook ,dale in ,shropshire1 or by carefully examining the carbonised impressions on shale under a simple microscope4 ,weiss applies the term ,paracalamostachys#gbg to cones of the ,calamostachys form1 but in which the manner of attachment cannot be made out4 ,such a cone as that of fig4 #ic should probably be referred to this sub-type of ,calamostachys in the absence of definite evidence as to the position of the sporangia4 ,another term ,stachannularia1 originally used by ,weiss as a genus#gbh1 was afterwards#gbi applied to cones of the same general type as ,calamostachys1 in which the sporangiophores have the form of thorn-like structures bearing on their upper side a lamellar expansion4 ,there is however some doubt as to the correct interpretation of the features associated with cones included in ,stachannularia2 for an account of such forms reference must be made to the writings of ,weiss1 ,renault#gcj1 ,solms-,laubach#gca and others#gcb4 ,calamostachys cones have been found in organic union with branches bearing leaves of the ,annularia type1 also with ,calamocladus foliage1 and the branches bearing such cones have been found in actual connection with ,calamitean stems4 ,the association of cones and vegetative stems and branches is shown in tabular form on p4 #cfc4 #b4 ,palaeostachya#gcc4 ,in this genus the general habit agrees with that of ,calamostachys1 and in imperfectly preserved specimens it may be impossible to discriminate between ,calamostachys and ,palaeostachya4 ,the latter form is characterised by the attachment of the sporangiophores in the axil of the sterile bracts1 or immediately above them1 as shown in figs4 #ig and #ih4 ,,examples4 ,palaeostachya vera sp4 nov41 ,p4 pedunculata ,will4 afford examples of this form of strobilus4 ,the genus ,palaeostachya includes several species previously described under the genus ,volkmannia#gcd4 ,strobili of this generic type are known in organic association with ,annularian branches1 as well as with ,calamocladus and ,calamites4 #c4 ,macrostachya4 ,this generic name was originally applied by ,schimper#gce to certain forms of ,calamitean stems1 of the type afterwards referred to the sub-genus ,calamitina by ,weiss1 bearing long and thick cones4 ,the name is1 however1 more appropriately restricted to strobili1 which differ from the two preceding genera in their greater length 7#ad-af cm47 and in the more crowded and imbricating whorls of bracts4 ,the internodes of the cones are very short1 and each whorl of bracts consists of about #bj coherent members separated at the periphery of the disc into short pointed teeth4 ,the internal structure of ,macrostachya has not been satisfactorily determined4 ,an account by ,renault#gcf of a petrified specimen does not present a very clear idea as to the structural features of this form of ,calamitean strobilus4 ,,the ,,association ,,of ,,calamitean ,,vegetative ,,shoots ,,and ,,cones4 ,strobilus ,foliage-shoot ,stem ---------------------------------------- ------------------------------- ,calamostachys ,annularia ramosa ,calamites ramosus 7,stachannularia7 ,weiss ,artis ramosa ,weiss#gcg ,c4 7,stachannularia7 ,a4 sphenophylloides ,stem bearing verticils of calathifera ,zenk4 long and narrow ,weiss#gch leaves#gci4 ,probably a young ,calamites ,c4 7,stachannularia7 ,a4 stellata tuberculata 7,stern47 7,schloth47#gdj ,calamites sp4#gda 7,a4 longifolia ,brongn47 ,c4 ,solmsi#gdb ,weiss ,calamocladus sp4 ,calamites 7,calamitina7 sp4 ,c4 longifolia ,calamocladus sp4 7,stern47#gdc ,palaeostachya ,calamocladus pedunculata ,will4#gdd ,p4 arborescens ,calamites 7,stern47#gde 7,stylocalamites7 arborescens 7,stern47 ,macrostachya#gdf ,calamocladus ,calamites 7,calamitina7 equisetiformis sp4 7,schloth47 ,sidenote3 ,,huttonia4 ,the generic name ,huttonia1 suggested by ,sternberg#gdg in #ahcg1 is applied to cones which closely resemble ,macrostachya in habit1 but differ--so far as our scanty knowledge enables us to judge--in the arrangement of the members4 ,the student must refer to ,weiss#gdh1 ,solms-,laubach#gdi and other writers#gej for a further account of these types1 and of another rare and little-known form of cone1 called by ,weiss ,cingularia#gea4 ,macrostachyan cones have been found attached to stems of ,calamites which are included in the sub-genus ,calamitina 7p4 #cfg74 ,the larger size of ,macrostachya as a distinguishing feature is not always a safe test2 some cones which belong to ,palaeostachya e4g4 ,p4 arborescens ,sternb4 and ,calamostachys 7e4g4 ,c4 ,solmsi7 are much thicker and larger than the majority of species of these two genera4 ,it would appear from the examples selected to illustrate the connection between strobili and vegetative shoots1 that the ,annularia type of branch usually bears cones which conform to the genus ,calamostachys 7,stachannularia72 while the ,asterophyllitean branches--,calamocladus--are associated with ,palaeostachya and ,macrostachya4 ,but this rule is not constant1 and we are not in a position to speak of cones of a particular type as necessarily characteristic of definite types of ,calamitean shoots4 ,although it is admitted by the great majority of ,palaeobotanists that the ,calamites were all true ,vascular ,cryptogams1 the older view that some members of the ,calamarieae are gymnospermous has not been given up by ,renault#geb4 ,this observer has recently described some seeds which he believes were borne by ,calamitean stems2 he admits1 however1 that no undoubted female cones of ,calamodendron have so far been found4 ,in view of the unsatisfactory evidence on which ,renault's opinion is based1 we need not further discuss the questions which he raises4 ,the following specimens in the ,williamson ,cabinet in the ,british ,museum1 may be found useful in illustration of the structure of ,calamites4 ,stems4 7i4 ,arthropitys47 ,young twigs and small branches #a1 #b1 #f1 #aj1 #ad1 #ai1 #aaf991 #ajjb1 #ajjg1 #ajbj4 ,older stems 7transverse sections7 #ae-ag1 #fb1 #gg-hg1 #aae a1 #aag991 #aah991 #abj1 #abb99-abd991 #aicc ,a1 #aicd1 #aida4 7,tangential sections7 #bj1 #bd1 #bf1 #cg1 #ch1 #di1 #ij1 #ia1 #acj1 #ach1 #aicg1 #aidc4 7,radial sections7 #bj1 #bj ,a1 #ba1 #bb1 #dh1 #fe-fh1 #hc-ia1 #acg991 #ach991 #aicg4 7ii4 ,arthrodendron7 #cf1 #cg1 #ch1 #eb1 #ed4 ,roots4 #acce1 #acdg1 #acej1 #acef4 ,strobili4 i4 ,calamostachys ,binneyana4 #iia1 #iif1 #iig1 #ajjj1 #ajjc1 #ajje1 #ajjg1 #ajjh1 #ajaa1 #ajac1 #ajaf1 #ajag1 #ajbb1 #ajbc1 #ajcg ,a1 #ajdc4 ii4 ,c4 ,casheana4 #ajbd1 #ajbe1 #aehg1 #aehh4 iii4 ,palaeostachya vera4 #aaj1 #aefd1 #aefg1 #aefi1 #aegi1 #aehc4 ,,iii4 ,pith-casts of ,calamites4 ,a4 ,calamitina4 ,b4 ,stylocalamites4 ,c4 ,eucalamites4 ,palaeobotanical literature contains a large number of species of ,calamites founded on pith-casts alone4 ,many of these so-called species are of little or no value botanically1 but while we may admit the futility of attempting to recognise specific types in the same sense as in the determination of recent plants1 it is necessary to pay attention to such characters as are likely to prove of value for descriptive and comparative purposes4 ,from the nature of the specimens it is clear that many of the differences may be such as are likely to be met with in different branches of the same species1 while in others the pith-casts of distinct species or genera may be almost identical4 ,the most striking differences observable in ,calamite casts are in the character of the internodes1 the infranodal canals1 the number and disposition of branch-scars1 and other surface features4 ,occasionally it is possible to recognise certain anatomical characters in the coaly layer which often surrounds a shale- or sandstone-cast1 and the surface of a well preserved cast may give a clue to the nature of the wood in the faint outlines of cells which can sometimes be detected on the cast itself#gec4 ,the breadth of the carbonaceous envelope on a cast has been frequently relied on by some writers as an important character4 ,it has been suggested#ged that we may arrive at the original thickness of the wood of a stem by measuring the coaly layer and multiplying the breadth by #bg2 the explanation being that a zone of wood #bg mm4 in thickness is reduced in the process of carbonisation to a layer #a mm4 thick4 ,the breadth of the coal on the same form of cast may vary considerably2 on this account1 and for various other reasons1 such a character can have but little value4 ,our knowledge of anatomy may often help us to interpret certain features of internal casts and to appreciate apparently unimportant details4 ,one occasionally notices that a ,calamite pith-cast has large infranodal canals1 and in some specimens each internodal ridge may be traversed by a narrow median line or small groove2 large infranodal canal casts suggest the type of stem referred to the subgenus ,arthrodendron1 and the median line on the ridges may be due to bands of hard tissue in each principal medullary ray4 ,in attempting to identify pith-casts the student must keep in view the probable differences presented by the branching rhizome1 the main aerial branches and the finer shoots of the same individual4 ,the long internodal ridges of some casts may be mistaken for the parallel veins of such a leaf as ,cordaites1 a ,palaeozoic ,gymnosperm1 if there are no nodes visible on the specimen4 ,the fossil figured by ,lindley and ,hutton#gee as ,poacites1 and regarded by them as a ,monocotyledon1 is no doubt a portion of a ,calamite with very long internodes4 ,an interesting example of incorrect determination has recently been pointed out by ,nathorst#gef in the case of certain casts from ,bear ,island1 originally described by ,heer as examples of ,calamites2 the vertical rows of leaf-trace casts on a ,knorria were mistaken for the ribs of a ,calamite stem4 ,the specimens in the ,stockholm ,museum fully bear out ,nathorst's interpretation4 ,the undulating course of internodal ridges and grooves is not in itself a character of specific value4 ,if a ,calamite stem were bent slightly1 the wood and medullary-ray tissues on the concave side might adapt themselves to the shortening of the stem by becoming more or less folded1 and a cast of such a stem would show undulating ridges and grooves on one side and straight ones on the other#geg4 ,a convenient classification of ,calamite casts was proposed by ,weiss in #ahhd1 founded chiefly on the number and manner of occurrence of branch-scars--or rather branch-depressions--on the surface of pith-casts4 ,weiss#geh recognised the imperfection of his proposed grouping1 and ,zeiller#gei has also expressed reasonable doubts as to the scientific value of such group-characters4 ,weiss instituted three subgenera--,calamitina1 ,eucalamites and ,stylocalamites1 which are made use of as convenient terms in descriptive treatment of ,calamite casts4 ,the following account of a few of the more typical casts may serve to illustrate the methods employed in the description of such specimens2 the synonomy given for the different species is not intended to be complete1 but it is added with a view to drawing attention to the necessity for careful comparison in systematic work4 ,a4 ,calamitina4 ,illustration3 ,,fig4 #ii4 ,calamites 7,calamitina7 ,gpperti 7,ett474 b1 branch scars4 ,from a specimen in the ,manchester ,museum1 ,owens ,college4 nat4 size4 ,this sub-genus of ,calamites1 as instituted by ,weiss#gfj1 includes ,calamitean stems or branches1 which are characterised by the periodic occurrence of branch-whorls usually represented by fairly large oval or circular scars just above a nodal line 7figs4 #ii1 #ajj and #aja74 ,the branch-scars may form a row of contiguous discs1 or a whorl may consist of a smaller number of branches which are not in contact basally4 ,a form described by ,weiss as ,c4 pauciramis1 ,weiss#gfa1 has only one branch in each whorl1 as represented by a single large oval scar on some of the nodes of the cast4 ,a stem of this form is by no means a typical ,calamitina1 but it serves to show the existence of forms connecting ,weiss' sub-genera ,calamitina and ,eucalamites4 ,the number of internodes and nodes between the branch whorls varies in different specimens1 and is indeed not constant in the same plant4 ,each nodal line bears numerous elliptical scars which mark the points of attachment of leaves2 each branch-whorl is situated immediately above a node1 and in some forms this nodal line pursues a somewhat irregular course across the stem1 following the outlines of the several branch-scars#gfb4 ,the surface of the internodes is either perfectly smooth or it is more frequently traversed by short longitudinal ridges or grooves probably representing fissures in the bark of the living stem2 these are indicated by lines in fig4 #ii and by elongated elliptical ridges in fig4 #aja4 ,on young stems the leaves are occasionally found in place1 as for example in an example figured by ,weiss#gfc 7,c4 ,gpperti71 or we may have leaf-verticils still in place in much older and thicker branches#gfd 7cf4 fig4 #he1 p4 #ccj74 ,it occasionally happens that the bark of ,calamitina stems has been preserved as a detached shell#gfe reminding one of the sheets of ,birch bark often met with in forests1 the separation being no doubt due in the fossil as in the recent trees to the manner of occurrence of the cork-cambium4 ,in a few cases branches have been preserved still attached to a stem or branch of higher order2 examples of such specimens are figured by ,lindley and ,hutton#gff1 ,stur#gfg1 and others4 ,grand',eury#gfh has given an idealised drawing of a typical ,calamitina bearing a whorl of branches with the foliage and habit of ,asterophyllites equisetiformis4 ,the specimen on which this drawing is based is in the ,natural ,history ,museum1 ,paris2 it shows ,asterophyllitean branches in organic connection with a ,calamitean stem1 but it is not quite clear if the stem is a true ,calamitina4 ,a large drawing of this interesting specimen is given by ,stur#gfi in his monograph on ,calamites1 also a smaller sketch by ,renault#ggj in his ,cours de botanique fossile4 ,similar branches of the ,asterophyllites type attached to an undoubted ,calamitina are figured also by ,lindley and ,hutton4 ,there is1 in short1 good evidence that stems of this sub-genus bore branches with ,asterophyllitean shoots4 ,the wood of stems of the ,calamitina group of ,calamites1 in some instances at least1 was of the ,arthropitys type2 this has been shown to be the case in some ,french specimens from the ,commentry coal-field#gga and in others described by ,stur#ggb4 ,the pith-casts of ,calamitina are characterised by comparatively short internodes separated by deep nodal constrictions1 as shown in fig4 #ajj4 ,from ,permian specimens from ,neu ,paka in ,bohemia1 described by ,stur#ggc1 we learn that there were the usual ,calamite diaphragms bridging across the wide pith-cavity at each node4 ,such a cast as that shown in fig4 #ajj is often referred to as ,calamites approximatus ,brongn42 the length of the internodes and the periodic occurrence of branch-scars in the form of circular or oval depressions along a nodal line enable us to recognise the ,calamitina casts4 ,weiss#ggd points out that in pith-casts of this form the branch-scars occur on the nodal constriction1 and not immediately above the node as is the case on the surface of a typical ,calamitina4 ,this distinction is however of little or no value2 the point of attachment of a branch may be above the nodal line1 while on the pith-cast of the same stem the point of origin of the vascular bundles of the branch is on the nodal constriction#gge4 ,the specimen shown in fig4 #ajj illustrates the appearance of a ,calamitina cast4 ,there is a verticil of branch-scars on the lowest nodal constriction2 on the right of the pith-cast the broad band of wood is faintly indicated by the smooth surface of the rock 7x74 ,other examples demonstrating the existence of a broad woody cylinder in ,calamitina stems have been figured by ,weiss#ggf and other writers1 and some good examples may be seen in the ,british ,museum4 ,illustration3 ,,fig4 #ajj4 ,calamites 7,calamitina7 approximatus ,brongn4 ,lower ,coal-,measures of ,ayrshire4 x1 impression of the wood4 7,from a specimen in the collection of ,mr ,r4 ,kidston47 ,we have so far noticed the connection of certain forms of pith-casts 7e4g4 ,calamites approximatus71 and ,asterophyllitean shoots with stems of the sub-genus ,calamitina4 ,as regards the strobili our knowledge is far from satisfactory4 ,stur#ggg figures some fertile branches bearing long and narrow strobili1 either ,palaeostachya or ,calamostachys1 in close association with ,calamitina stems1 and ,renault and ,zeiller#ggh give illustrations of the association of ,calamitina stems with large strobili of the ,macrostachya form4 ,before ,weiss proposed the term ,calamitina1 various authors had figured this form of ,calamite under a distinct generic name 7e4g4 ,hippurites of ,lindley and ,hutton#ggi1 ,cyclocladia#ghj1 ,macrostachya#gha1 c474 ,stems of this type have also been described by more recent writers under different names1 and considerable confusion has been caused by the use of numerous generic designations for forms of ,calamitina4 ,some small fragments of ,calamitina stems were described by ,salter#ghb in #ahfc as portions of a new species of the ,crustacean ,eurypterus 7,e4 mammatus74 ,in #ahfi ,grand',eury proposed the generic name ,calamophyllites#ghc for stems bearing verticils of ,asterophyllites shoots2 his description of such stems agrees with ,weiss' ,calamitina1 but as ,grand',eury's name is used in a narrower sense as implying a connection with ,asterophyllites1 it is more convenient to adopt ,weiss' term in spite of the priority of ,calamophyllites4 ,in the ,fossil flora of ,commentry we find some flattened stems of the ,calamitina type described under different generic names1 as ,arthropitys approximatus#ghd and as ,macrostachya#ghe4 ,the determination of distinct species of the sub-genus ,calamitina is rendered almost hopeless by the variation in the different branches of the same individual1 and by the difficulty of connecting surface-impressions with casts of the pith-cavity4 ,a typical example of the ,calamitina type of ,calamites was figured by ,sternberg#ghf in #ahba as ,calamites varians4 ,this has been adopted by ,weiss#ghg as a comprehensive species including several different #8forms' of stems1 which differ from ,sternberg's fossil in such points as the number of nodes between the branch-whorls and the number of branches in each whorl4 ,the result of this system of nomenclature is the separation of portions of one specific type under different form-names4 ,it must be clearly recognised that accurate specific diagnoses are practically impossible when we have to deal with fragments of plants1 some of which are mere pith-casts1 while others show the surface features4 ,the specimen represented in fig4 #ii agrees with a stem described by ,ettingshausen#ghh in #ahee as ,calamites ,gpperti1 and as a matter of convenience a member of the ,calamitina group showing such characters may be referred to as ,calamites 7,calamitina7 ,gpperti 7,ett474 ,the following list1 which includes a few synonyms of this form1 may suffice to illustrate the difficulties connected with accurate systematic determinations4 ,calamites 7,calamitina7 ,gpperti 7,ett474 ,fig4 #ii4 #ahee4 ,calamites ,gpperti1 ,ettingshausen#ghi4 #ahfi4 ,calamites 7,calamophyllites7 ,gpperti1 ,grand',eury#gij4 #ahgd4 ,cyclocladia major1 ,feistmantel#gia4 #ahgd4 ,calamites verticillatus1 ,williamson#gib4 #ahgf4 ,calamitina ,gpperti1 ,weiss#gic4 #ahhd4 ,calamites 7,calamitina7 varians abbreviatus1 ,weiss#gid4 #ahhd4 ,calamites 7,calamitina7 varians inconstans1 ,weiss#gie4 #ahhg4 ,calamites ,sachsei1 ,stur#gif4 #ahhh4 ,calamophyllites ,gpperti1 ,zeiller#gig4 ,this species is characterised by the smooth bark1 which may be traversed by a few irregular longitudinal fissures2 most of the nodes bear a series of small leaf-scars1 and at fairly regular intervals a node is immediately succeeded by a circle of contiguous branch-scars1 #h-ab in a whorl4 ,the pith-cast of this type of stem has short ribbed internodes separated by rather deep nodal constrictions2 the branch-whorls being represented by a series of pits on the nodal constrictions recurring at corresponding intervals to the whorls of branch-scars on the surface of the stem4 ,leaves narrow and linear in form1 like those on ,asterophyllitean branches1 are occasionally associated with this type of stem4 ,illustration3 ,,fig4 #aja4 ,calamites 7,calamitina7 sp4 ,from a specimen in the ,british ,museum4 7,after ,carruthers47 ,slightly reduced4 ,the fragment of a ,calamitina stem shown in fig4 #aja is the counterpart of a specimen originally figured by ,steinhauer#gih in #ahah as a species of ,phytolithus4 ,this may be specifically identical with ,c4 ,gpperti2 but it is better to speak of so small a specimen as merely one of the ,calamitina stems1 to be compared with ,calamites 7,calamitina7 ,gpperti4 ,the specimen measures #ade cm4 in length and #g cm4 in breadth4 ,the form of pith-cast represented in fig4 #ajj is no doubt that of one of the ,calamitina species1 but as it is seldom possible to determine the connection between such casts and the particular species of stems to which they belong1 they are often referred to as ,calamites 7,calamitina7 approximatus 7,brongn474 ,the specimen of which fig4 #ajj is a photograph was originally described and figured by ,mr ,kidston#gii from the lower ,coal-,measures of ,ayrshire4 ,both ,calamites 7,calamitina7 ,gpperti 7,ett47 and ,c4 7,calamitina7 approximatus 7,brongn47 are recorded from the ,transition1 ,middle and ,lower ,coal-,measures#hjj4 ,b4 ,stylocalamites4 ,in the members of this sub-genus the branch-scars are either irregular in their occurrence or absent4 ,in some ,calamites the branch-scars are very few and far between1 and other species appear to have been almost without branches2 pith-casts of such stems may be referred to the sub-genus ,stylocalamites#hja4 ,an exceedingly common ,calamitean cast1 ,c4 ,suckowi ,brongn4 7fig4 #hb7 affords a good illustration of this type of stem4 ,in the specimen shown in fig4 #hb we have a cast of a rhizome1 which is rather exceptional in showing three branches in connection with one another4 ,the appearance of the fossil suggests a rhizome1 rather than an aerial shoot1 bearing lateral branches2 the narrowing of the branches and the rapid decrease in the length of the internodes towards the point of attachment being features associated with rhizomes rather than with aerial branches4 ,calamites 7,stylocalamites7 ,suckowi1 ,brongn4 ,fig4 #hb4 #ahah4 ,phytolithus sulcatus1 ,steinhauer#hjb4 #ahbe4 ,calamites decoratus1 ,artis#hjc4 #ahbh4 ,calamites ,suckowi1 ,brongniart#hjd4 #ahcc4 ,calamites cannaeformis1 ,lindley and ,hutton#hje4 ,for more complete lists of synonyms of this species reference should be made to ,kidston#hjf1 ,zeiller#hjg1 and other authors4 ,casts of ,calamites ,suckowi are characterised by flat or slightly convex internodal ridges separated by shallow depressions1 the ridges are rounded at the upper end of each internode1 and usually bear circular casts of infranodal canals4 ,there are some unusually large examples of casts of this species in the ,british ,museum from the ,radstock ,coal-,measures2 one of these has a length of #ha cm41 and a diameter of #bg cm4 ,specimens are not infrequently found with verticils of slender roots in close proximity to the nodes of the cast2 figures of such root-bearing casts have been given by ,lindley and ,hutton#hjh1 ,weiss#hji1 and other authors4 ,renault#haj has drawn attention to the thinness of the layer of wood which is often associated with large casts of ,c4 ,suckowi2 he concludes that the stems must have possessed little or no secondary wood4 ,in a more recent work by ,grand',eury#haa ,calamites ,suckowi is spoken of as having had wood of the ,calamodendron type1 but as wood of this kind has not been found in ,england1 it is suggested that the plant may not have assumed an arborescent habit until late in the ,coal-,measure period4 ,during the ,lower and ,middle ,coal-,measures1 at which horizon it commonly occurs in ,england1 it may have been herbaceous4 ,this suggestion has little to commend it2 the close agreement between ,c4 ,suckowi from ,english and ,french localities points to a plant of the same form1 and we have no satisfactory evidence as to any difference in stem-structure in the two cases4 ,stur has figured a specimen of a ,calamite cast1 which he compares with ,c4 ,suckowi1 surrounded by a band of silicified wood apparently of the ,arthropitys type4 ,from this and other facts it would appear probable that some of the ,english stems with the ,arthropitys structure possessed casts referable to ,calamites 7,stylocalamites7 ,suckowi4 ,we are not in a position to speak with confidence as to the strobili of ,c4 ,suckowi1 but ,stur adduces evidence in support of a connection between this species of ,calamite and certain ,asterophyllitean branches 7,calamocladus equisetiformis7 bearing ,calamostachyan cones4 ,he does not appear to have found the foliage-shoots and stems in organic contact1 but draws this conclusion from the association of the fertile branches and stems in the same rocks#hab4 ,this species is abundant in the ,lower1 ,middle and ,upper ,coal-,measures2 it has also been recorded from the ,millstone ,grit#hac4 ,c4 ,eucalamites4 ,in this sub-genus branch-scars occur on every node2 the scars never form a contiguous whorl as in ,calamitina1 but there may be from #c to #aj on each node4 ,the scars of successive nodes often alternate in position1 and thus form more or less regular vertical series as shown in fig4 #ajb4 ,the most obvious feature as regards the arrangement of the branch-scars is their spiral disposition on the surface of the pith-cast4 ,the internodes are fairly uniform in length1 and there is no periodic recurrence of narrower internodes as in ,calamitina4 ,from an examination of specimens of ,eucalamites in which the pith-cast is covered with a coaly layer representing the carbonised remains of the wood and cortex1 it would appear that the surface of the stems was practically smooth4 ,the coaly investment on ,eucalamites casts varies considerably in thickness#had2 it is very unsafe to make use of the thickness of this layer as a test of the breadth of the wood in ,calamitean stems4 ,the branch-scars as seen in a surface-view of a stem are situated a little above the nodal lines1 while depressions on the pith-casts occur in the slight nodal constriction or immediately above it4 ,small leaf-scars have been described as occurring on the nodes between the branch-scars in specimens showing the surface features#hae4 ,the species long known as ,calamites cruciatus ,sternb4 is usually taken as the type of the sub-genus ,eucalamites4 ,weiss#haf has subdivided this species into several #8forms1' which he bases on the number of branch-scars on each node and on other characters2 a more extended subdivision of ,c4 cruciatus has recently been made by ,sterzel#hag1 who admits the impossibility of separating the specific forms by means of the data at our disposal1 but for purposes of geological correlation he prefers to express slight differences by means of definite #8forms' or varieties4 ,the more comprehensive use of the specific name cruciatus as adopted by ,zeiller in his ,flore de ,valenciennes#hah is1 ,i believe1 the better method to adopt4 ,the specimen shown in fig4 #ajb affords a good example of a typical ,calamites cruciatus1 it was found in the ,middle ,coal-,measures near ,barnsley1 ,yorkshire4 ,illustration3 ,,fig4 #ajb4 ,calamites 7,eucalamites7 cruciatus1 ,sternb4 ,from a specimen in the ,barnsley ,museum1 ,yorkshire4 nat4 size4 ,calamites 7,eucalamites7 cruciatus 7,sternb474 ,fig4 #ajb4 #ahbf4 ,calamites cruciatus1 ,sternberg#hai4 #ahbh4 ,calamites cruciatus1 ,brongniart#hbj4 #ahca4 ,calamites alternans1 ,germar and ,kaulfuss#hba4 #ahcg4 ,calamites approximatus1 ,lindley and ,hutton#hbb4 #ahgg4 ,calamodendrofloyos cruciatus1 ,grand',eury#hbc4 #ahgh4 ,calamodendron cruciatum1 ,zeiller#hbd4 #ahhd4 ,calamites 7,eucalamites7 cruciatus ternarius1 ,weiss#hbe4 #ahhd4 quaternarius1 ,weiss#hbe4 #ahhd4 genarius1 ,weiss#hbe4 #ahhd4 multiramis1 ,weiss#hbe4 #ahhh4 ,calamites 7,calamodendron7 cruciatus1 ,zeiller#hbf4 ,this species occurs in the ,upper1 ,middle and ,lower ,coal-,measures#hbg4 ,the casts of the cruciatus type have been found associated with wood possessing the structural features of the sub-genus ,calamodendron#hbh1 but our knowledge of the structure of the stem1 and of the fertile branches of ,c4 cruciatus is very imperfect4 ,a restoration of ,calamites 7,eucalamites7 cruciatus is given by ,stur#hbi in his classic work on the ,calamites1 but he does not make quite clear the supposed connection with the stems and the fertile shoots of the ,asterophyllites type#hcj which he describes4 ,another member of the ,eucalamites group1 which is better known as regards its foliage-shoots1 is ,calamites ramosus1 a species first described by ,artis#hca in #ahbe4 ,stems of this species have been found in connection with the branches and leaves of the ,annularia#f type1 bearing ,calamostachys#hcb cones4 ,in all probability pith-casts included in the sub-genus ,eucalamites belonged to stems with foliage-shoots and probably also with cones of more than one form4 ,sidenote3 ,,nomenclature4 ,in the above account of a few common pith-casts it has been pointed out that there is occasionally satisfactory evidence for connecting certain casts with wood of a particular structure1 and with sterile and fertile foliage-shoots of a definite type4 ,it is1 however1 impossible in many cases to recognise with any certainty the leaf-bearing branches and strobili of the different casts of ,calamites2 it is equally impossible to determine what type of pith-cast or what type of foliage-shoots belongs to petrified stem-fragments in which it is possible to investigate the microscopical features4 ,the scattered and piece-meal nature of the material on which our general knowledge of ,calamitean plants is based1 necessitates a system of nomenclature which is artificial and clumsy2 but the apparent absurdity of attaching different names to fragments1 which we believe to be portions of the same genus1 is of convenience from the point of view of the geologist and the systematist4 ,as our material increases it will be possible to further simplify the nomenclature for ,calamarian plants1 but it is unwise to allow our desire for a simpler terminology to lead us into proposals which are based rather on suppositions than on established fact4 ,if it were possible to discriminate between pith-casts of stems having the different anatomical characters designated by the three sub-genera1 ,arthropitys1 ,arthrodendron and ,calamodendron1 the genus ,calamites might be used in a much narrower and probably more natural sense than that which we have adopted4 ,the tests made use of by some authors for separating pith-casts of ,calamodendron and ,arthropitys stems do not appear to be satisfactory2 we want some term to apply to all ,calamitean casts irrespective of the anatomical features of the stems1 or of the precise nature of the foliage-branches4 ,as used in the present chapter1 ,calamites stands for plants differing in certain features but possessing common structural characters1 which must be defined in a broad sense so as to include types which may be worthy of generic rank1 but which for convenience sake are included in a comprehensive generic name4 ,the attempts to associate certain forms of foliage with ,arthropitys on the one hand and with ,calamodendron on the other1 cannot be said to be entirely satisfactory2 we still lack data for a trustworthy diagnosis of distinct ,calamarian genera which shall include external characters as well as histological features4 ,if we restricted the genus ,calamites to stems with an ,arthropitys structure and an ,asterophyllitean foliage1 we should be driven into unavoidable error4 ,within certain limits it is possible to distinguish generically or even specifically between petrified branches1 and we already possess material enough for fairly complete diagnoses founded on internal structure2 but it is not possible to make a parallel classification for pith-casts and foliage-shoots4 ,for this reason1 and especially bearing in mind the importance of naming isolated foliage-shoots and stem-casts for geological purposes1 ,i believe it is better to admit the artificially wide application of the name ,calamites1 and to express more accurate knowledge1 where possible1 by the addition of a subgeneric term4 ,in dealing with distinctions exhibited by ,calamitean stems it may be advisable to make use of specific names1 but we must keep before us the probability of the pith-cast and petrified stem-fragment of the same plant receiving different specific names4 ,if the structural type is designated by a special sub-genus1 this will tend to minimise the anomaly of using more than one binominal designation for what may be the same individual4 ,sidenote3 ,,calamites ,,and ,,equisetum4 ,the following summary may serve to bring together the different generic and subgeneric terms which have been used in the foregoing account of ,calamites4 ,,calamites4 ,subgenera having reference to the method of branching as seen in casts or impressions of the stem-surface or in pith-casts4 ,calamitina1 ,eucalamites1 ,stylocalamites4 ,subgenera founded on anatomical characters in stems and branches4 ,arthropitys1 ,calamodendron1 ,arthrodendron 7new sub-genus substituted for ,calamopitys74 ,genus proposed for roots of ,calamites before their real nature was recognised4 ,the name refers to anatomical characters4 ,astromyelon4 ,genera of which some species1 if not all1 are the leaf-bearing branches of ,calamites4 ,calamocladus 7including ,asterophyllites71 ,annularia4 ,generic names applied to strobili belonging to ,calamites4 ,calamostachys1 ,palaeostachya1 ,macrostachya1 etc4 ,genus including impressions of ,calamite roots4 ,pinnularia4 ,,iv4 ,conclusion4 ,a brief sketch of the main features of ,calamites suffices to bring out the many points of agreement between the arborescent ,calamite plants and the recent ,equisetums4 ,the slight variation in morphological character among the present-day ,horse-tails1 contrasts with the greater range as regards structural features among the types included in ,calamites4 ,the ,horse-tails probably represent one of several lines of development which tend to converge in the ,palaeozoic period2 the ,calamite itself would appear to mark the culminating point of a certain phylum of which we have one degenerate but closely allied descendant in the genus ,equisetum4 ,we shall1 however1 be in a better position to consider the general question of plant-evolution after we have made ourselves familiar with other types of ,palaeozoic plants4 ,grand',eury's#hcc striking descriptions of forests of ,calamites in the ,coal-,measures of central ,france1 enable us to form some idea of the habit of growth of these plants with their stout branching rhizomes and erect aerial shoots4 ,by piecing together the evidence derived from different sources we may form some idea of the appearance of a living ,calamite4 ,a stout branching rhizome ascended obliquely or spread horizontally through sand or clay1 with numerous whorls or tufts of roots penetrating into swampy soil4 ,from the underground rhizome strong erect branches grew up as columnar stems to a height of fifty feet or more2 in the lower and thicker portions the bark was fissured and somewhat rugged1 but smoother nearer the summit4 ,looking up the stem we should see old and partially obliterated scars marking the position of a ring of lateral branches1 and at a higher level tiers of branches given off at regular or gradually decreasing intervals1 bearing on their upper portions graceful green branchlets with whorls of narrow linear leaves4 ,on the younger parts of the main shoot rings of long and narrow leaves were borne at short intervals1 several leaf-circles succeeding one another in the intervals between each radiating series of branches4 ,on some of the leaf-bearing branchlets long and slender cones would be found here and there taking the place of the ordinary leafy twigs4 ,passing to the apical region of the stem the lateral branches given off at a less and less angle would appear more crowded1 and at the actual tips there would be a crowded succession of leaf-segments forming a series of overlapping circles of narrow sheaths with thin slender teeth bending over the apex of the tree4 ,thus we may feebly attempt to picture to ourselves one of the many types of ,calamite trees in a ,palaeozoic forest1 growing in a swampy marsh or on gently sloping ground on the shores of an inland sea1 into which running water carried its burden of sand and mud1 and broken twigs of ,calamites and other trees which contributed to the ,coal ,period sediments4 ,the large proportions of a ,calamite tree are strikingly illustrated by some of the broad and long pith-casts occasionally seen in ,museums2 in the ,breslau ,collection there is a cast of a stem belonging to the sub-genus ,calamitina1 which measures about #b m4 in length and #bc cm4 in breadth1 with #cf nodes4 ,in the ,natural ,history ,museum1 ,paris1 there is a cast nearly #b metres long and more than #bj cm4 wide1 which is referred to the sub-genus ,calamodendron4 ,e4 ,,archaeocalamites4 ,in the ,upper ,devonian and ,culm rocks casts of a well-defined ,calamitean plant are characteristic fossils2 stems1 leaf-bearing branches1 roots and cones have been described by several authors1 and the genus ,archaeocalamites has been instituted for their reception4 ,although this genus agrees in certain respects with ,calamites1 and as recent work has shown this agreement extends to internal structure1 it has been the custom to regard the ,lower ,carboniferous and ,devonian plants as genetically distinct4 ,the surface features of the stem-casts1 the form of the leaves1 and apparently the cones1 possess certain distinctive characters which would seem to justify the retention of a separate generic designation4 ,we may briefly summarise the characteristics of the genus as follows3-- ,pith-casts articulated1 with very slightly constricted nodes2 the internodes traversed by longitudinal ribs slightly elevated or almost flat1 separated by shallow grooves4 ,the ribs and grooves are continuous from one internode to another1 and do not usually show the characteristic alternation of ,calamites#hcd4 ,along the nodal line there are occasionally found short longitudinal depressions1 probably marking the points of origin of outgoing bundles4 ,branches were given off from the nodes without any regular order2 a pith-cast may have branch-scars on many of the nodes1 or there may be no trace of branches on casts consisting of several nodes4 ,the leaves#hce are in whorls2 in some cases they occur as free1 linear1 lanceolate leaves1 or on younger branches they are long1 filiform and repeatedly forked4 ,the structure of the wood agrees with that of some forms of ,arthropitys4 ,the strobili consist of an articulated axis bearing whorls of sporangiophores1 and each sporangiophore has four sporangia4 ,our knowledge of the fertile shoots is1 however1 very imperfect4 ,renault#hcf has recently described the structure of the wood in some small silicified stems of ,archaeocalamites from ,autun4 ,a large hollow pith is surrounded by a cylinder of wood consisting of wedge-shaped groups of xylem tracheids associated with secondary medullary rays2 at the apex of each primary xylem group there is a carinal canal4 ,the primary medullary rays appear to have been bridged across by bands of xylem at an early stage of secondary thickening1 as in the ,calamite of fig4 #hc1 ,d4 ,illustration3 ,,fig4 #ajc4 ,archaeocalamites scrobiculatus 7,schloth474 ,from a specimen in the ,woodwardian ,museum1 ,cambridge4 ,from the ,carboniferous limestone of ,northumberland4 nat4 size4 ,our knowledge of the cones of ,archaeocalamites is far from satisfactory4 ,renault#hcg has recently described a small fertile branch bearing a succession of verticils of sporangiophores2 each sporangiophore stands at right angles to the axis of the cone and bears four sporangia1 as in ,calamostachys4 ,it is not clear how far there is better evidence than that afforded by the association of the specimen with pith-casts of stems1 for referring this cone to ,archaeocalamites1 but the association of vegetative and fertile shoots certainly suggests an organic connection4 ,the cone described by the ,french author agrees with ,equisetum in the absence of sterile bracts between the whorls of sporangiophores4 ,it is an interesting fact that such a distinctly ,equisetaceous strobilus is known to have existed in ,lower ,carboniferous rocks4 ,stur#hch has also described ,archaeocalamites at considerable length2 he gives several good figures of stem-casts and foliage-shoots bearing long and often forked narrow leaves4 ,the same writer describes specimens of imperfectly preserved cones in which portions of whorls of forked filiform leaves are given off from the base of the strobilus#hci4 ,kidston#hdj published an important memoir on the cones of ,archaeocalamites in #ahhc1 in which he advanced good evidence in support of the view that certain strobili1 which were originally described as ,monocotyledonous inflorescences1 under the generic name ,pothocites#hda1 are the fertile shoots of this ,calamarian genus4 ,kidston's conclusions are based on the occurrence on the ,pothocites cones1 of leaves like those of ,archaeocalamites1 on the non-alternation of the sporangiophores of successive whorls1 and on the close resemblance between his specimens and those described by ,stur4 ,good specimens of the cones1 formerly known as ,pothocites1 may be seen in the ,botanical ,museum in the ,royal ,gardens1 ,edinburgh2 as they are in the form of casts without internal structure it is difficult to form a clear conception as to their morphological features4 ,the fossils included under ,archaeocalamites have been referred by different authors to various genera1 and considerable confusion has arisen in both generic and specific nomenclature4 ,the following synonomy of the best known species1 ,a4 scrobiculatus 7,schloth47 illustrates the unfortunate use of several terms for the same plant4 ,archaeocalamites scrobiculatus 7,schloth474 ,fig4 #ajc4 #agbj4 ,lithoxylon1 ,volkmann#hdb4 #ahbj4 ,calamites scrobiculatus1 ,schlotheim#hdc4 #ahbe4 ,bornia scrobiculata1 ,sternberg#hdd4 #ahbh4 ,calamites radiatus1 ,brongniart#hde4 #ahda4 ,pothocites ,grantoni1 ,paterson#hdf4 #aheb4 ,calamites transitionis1 ,gppert#hdg4 ---- ,stigmatocanna ,volkmanniana1 ibid4 ---- ,anarthrocanna tuberculata1 ibid4 ---- ,calamites variolatus1 ibid4 ---- ,c4 obliquus1 ibid4 ---- ,c4 tenuissimus1 ibid4 ---- ,asterophyllites elegans1 ibid4 #ahff4 ,calamites laticulatus1 ,ettingshausen#hdh4 ---- ,equisetites ,gpperti1 ibid4 ---- ,sphenophyllum furcatum1 ibid4 #ahgc4 ,asterophyllites spaniophyllus1 ,feistmantel#hdi4 #ahhj4 ,asterocalamites scrobiculatus1 ,zeiller#hej4 ,for other lists of synonyms reference may be made to ,binney#hea1 ,stur#heb1 ,kidston#hec and other authors4 ,some of the best specimens of this species are to be seen in the ,museums of ,breslau and ,vienna1 which contain the original examples described by ,gppert and ,stur4 ,an examination of the original specimens1 figured by ,gppert under various names1 enables one to refer them with confidence to the single species1 ,archaeocalamites scrobiculatus4 ,the generic name ,archaeocalamites1 which has been employed by some authors1 was suggested by ,schimper#hed in #ahfb1 as a subgenus of ,calamites1 on account of the occurrence of a deeply divided leaf-sheath1 attached to the node of a pith-cast1 which seemed to differ from the usual type of ,calamitean leaf4 ,the specimens described by ,schimper are in the ,strassburg ,museum2 the leaf-sheath which he figures is not very accurately represented4 ,the example given in fig4 #ajc shews very clearly the continuous course of the ribs and grooves of the pith-cast4 ,each rib is traversed by a narrow median groove which would seem to represent the projecting edge of some hard tissue in the middle of each principal medullary ray of the stem4 ,the specimen was found in a ,carboniferous limestone quarry1 ,northumberland2 there is a similar cast from the same locality in the ,museum of the ,geological ,survey4 ,affinities of ,archaeocalamites4 ,this genus agrees very closely with ,calamites both in the anatomical structure of the stem and in the verticillate disposition of the leaves4 ,the strobili appear to be ,equisetaceous in character1 and there is no satisfactory evidence of the existence of whorls of sterile bracts in the cone1 such as occur in ,calamostachys and in other ,calamitean strobili4 ,the continuous course of the vascular bundles of the stem from one internode to the next is the most striking feature in the ordinary specimens of the genus2 but it sometimes happens that the grooves on a pith-cast shew the same alternation at the node as in ,calamites4 ,this is the case in a specimen in the ,gppert collection in the ,breslau ,museum1 and ,feistmantel#hee has called attention to such an alternation in specimens from ,rothwaltersdorf4 ,in the true ,calamites1 on the other hand1 the usual nodal alternation of the vascular strands is by no means a constant character#hef4 ,stur#heg1 ,rothpletz#heh1 and other authors have pointed out the resemblance of ,archaeocalamites to ,sphenophyllum4 ,the deeply divided leaves of some ,sphenophyllums and those of ,archaeocalamites are very similar in form2 and the course of the vascular strands in ,sphenophyllum may be compared with that in ,archaeocalamites4 ,but the striking difference in the structure of the stele forms a wide gap between the two genera4 ,we have evidence that the ,calamites and ,sphenophyllums were probably descended from a common ancestral stock1 and it may be that in ,archaeocalamites1 some of the ,sphenophyllum characters have been retained2 but there is no close affinity between the two plants4 ,on the whole1 considering the age of ,archaeocalamites and the few characters with which we are acquainted1 it is probable that this genus is very closely related to the typical ,calamites1 and may be regarded as a type which is in the direct line of development of the more modern ,calamite and the living ,equisetum4 ,weiss#hei includes ,archaeocalamites as one of his subgenera with ,calamitina and others1 and it is quite possible that the genus has not more claim to stand alone than other forms at present included in the comprehensive genus ,calamites4 ,the student will find detailed descriptions of this genus in the works which have been referred to in the preceding pages4 ,,chapter ,,xi4 ,,ii4 ,,sphenophyllales4 ,sphenophyllum4 ,the genus ,sphenophyllum is placed in a special class1 as representing a type which cannot be legitimately included in any of the existing groups of ,vascular ,cryptogams4 ,although this ,palaeozoic genus possesses points of contact with various living plants1 it is generally admitted by palaeobotanists that it constitutes a somewhat isolated type among the ,pteridophytes of the ,coal-,measures4 ,our knowledge of the anatomy of both vegetative shoots and strobili is now fairly complete1 and the facts that we possess are in favour of excluding the genus from any of the three main divisions of the ,pteridophyta4 ,in ,scheuchzer's ,herbarium ,diluvianum there is a careful drawing of some fragments of slender twigs1 from an ,english locality1 bearing verticils of cuneiform leaves1 which the author compares with the common ,galium#hfj4 ,as regards superficial external resemblance1 the ,galium of our hedgerows agrees very closely with what must have been the appearance of fresh green shoots of ,sphenophyllum4 ,a twig of the same species of ,sphenophyllum is figured by ,schlotheim#hfa in the first part of his work on fossil plants2 he regards it as probably a fragment of some species of ,palm4 ,sternberg#hfb was the first to institute a generic name for this genus of plants1 and specimens were described by him in #ahbe as a species of the genus ,rotularia4 ,the name ,sphenophyllites was proposed by ,brongniart#hfc in #ahbb as a substitute for ,schlotheim's genus1 and in a later work#hfd the ,french author instituted the genus ,sphenophyllum4 ,dawson#hfe was the first to make any reference to the anatomy of this genus2 but it is from the examination of the much more perfect material from ,st4 tienne1 ,autun1 and other continental localities1 the ,north of ,england and ,pettycur in ,scotland1 by ,renault1 ,williamson1 ,zeiller and ,scott1 that our more complete knowledge has been acquired4 ,the affinity of ,sphenophyllum has always been a matter of speculation2 it has been compared with ,dicotyledons1 ,palms1 ,conifers 7,ginkgo and ,phyllocladus71 and various ,pteridophytes1 such as ,ophioglossum1 ,tmesipteris1 ,marsilia1 ,salvinia1 ,equisetum and the ,lycopodiaceae#hff4 ,sidenote3 ,,definition4 ,we may define the genus ,sphenophyllum as follows3-- ,stem comparatively slender 7#ae-ae mm4871 articulated1 usually somewhat tumid at the nodes2 the surface of the internodes is marked by more or less distinct ribs and grooves which do not alternate at the nodes1 but follow a straight course from one internode to the next4 ,a single branch is occasionally given off from a node4 ,adventitious roots are very rarely seen1 their surface does not show the ridges and grooves of the foliage-shoots4 ,the leaves are borne in verticils at the nodes1 those in the same whorl being usually of the same size1 but in some forms two of the leaves are distinctly smaller than the others4 ,each verticil contains normally #f1 #i1 #ab1 #ah or more leaves1 which are separate to the base and not fused into a sheath2 the number of leaves in a verticil is not always a multiple of six4 ,they vary in form from cuneiform with a narrow tapered base1 and a lamina traversed by several forked veins1 to narrow uninerved leaves and leaves with a lamina dissected into dichotomously branched linear segments4 ,the leaves of successive whorls are superposed4 ,the strobili are long and narrow in form1 having a length in some cases of #ab cm41 and a diameter of #ab mm42 they occur as shortly stalked lateral branches1 or terminate long leaf-bearing shoots4 ,the axis of the cone bears whorls of numerous linear lanceolate bracts fused basally into a coherent funnel-shaped disc1 bearing on its upper surface sporangiophores and sporangia4 ,the strobili are usually isosporous1 but possibly heterosporous in some forms4 ,the stem is monostelic1 with a triarch or hexarch triangular strand of centripetally developed primary xylem1 consisting of reticulate1 scalariform and spiral tracheae2 the protoxylem elements being situated at the blunt corners of the xylem-strand4 ,foliar bundles are given off1 either singly or in pairs1 from each angle of the central primary strand4 ,the secondary xylem consists of radially disposed reticulate or scalariform tracheae1 developed from a cambium-layer4 ,the phloem is made up of thin-walled elements1 including sieve-tubes and parenchyma4 ,both xylem and phloem include secondary medullary rays of parenchymatous cells4 ,the cortex consists in part of fairly thick-walled elements2 in older stems the greater part of the cortical region is cut off by the development of deep-seated layers of periderm4 ,the roots are apparently diarch in structure1 with a lacunar and smooth cortex4 ,the branch of ,sphenophyllum emarginatum ,brongn4 given in fig4 #aji shows the characteristic appearance of the genus as represented by this well-known species which ,brongniart figured in #ahbb4 ,the ,indian species shown in fig4 #aaa illustrates the occurrence of unequal leaves in the same whorl1 and in fig4 #aaj1 ,b1 we have a form of verticil in which the leaves are deeply divided into filiform segments4 ,a larger-leaved form is represented by ,s4 ,thoni1 ,mahr4 7fig4 #aaj1 ,a71 a species occasionally met with in ,permian rocks4 ,no specimens of ,sphenophyllum have so far been found attached to a thick stem2 they always occur as slender shoots1 which sometimes reach a considerable length4 ,one of the longest examples known is in the collection of the ,austrian ,geological ,survey2 the axis is #d mm4 in breadth and #he cm4 long1 bearing a slender branch #fa cm4 in length4 ,the manner of occurrence of the specimen as a curved slender stem on the surface of the rock suggests a weak plant1 which must have depended for support on some external aid1 either water or another plant4 ,the anatomical structure and other features do not favour the suggestion of some writers that ,sphenophyllum was a water-plant#hfg1 but there would seem to be no serious obstacle in the way of regarding it as possibly a slender plant which flung itself on the branches and stems of stronger forest trees for support4 ,a4 ,the anatomy of ,sphenophyllum4 ,the following account of the structural features of the stem and root is based on the work of ,renault#hfh1 ,williamson#hfi and ,williamson and ,scott#hgj4 ,we may first consider such characters as have been recognised in different examples of the genus1 and then notice briefly the distinguishing peculiarities of two well-marked specific types4 a4 ,stems4 i4 ,primary structure4 ,in a transverse section of a young ,sphenophyllum stem such as that diagrammatically sketched in fig4 #aje1 ,a1 we find in the centre the xylem portion of a single stele with a characteristic triangular form4 ,the primary xylem consists mainly of fairly large tracheae with numerous pits on their walls2 towards the end of each arm the tracheids become scalariform1 and at the apex there is a group of narrower spiral protoxylem elements4 ,in the ,british species there is a single protoxylem group at the apex of each arm1 but ,renault has described some ,french stems in which the stele appears to be hexarch1 having two protoxylem groups at the end of each of the three rays of the stele4 ,the primary xylem strand of ,sphenophyllum has therefore a root-like structure1 the tracheids having been developed centripetally from the three initial protoxylem groups4 ,this type of structure is typical of roots1 but it also occurs in the stems of some recent ,vascular ,cryptogams4 ,illustration3 ,,fig4 #ajd4 ,diagrammatic longitudinal section of ,sphenophyllum4 c1 outer cortex2 b1 space next the stele1 originally occupied by phloem etc42 a1 xylem strand4 7,after ,renault#hga47 #g4 ,as a rule the tissue next the xylem has not been petrified1 but in exceptionally well-preserved examples it is seen to consist of a band of thin-walled elements1 of which those in contact with the xylem may be spoken of as phloem1 and those beyond as the pericycle4 ,succeeding this band of delicate tissue there is a broader band of thicker-walled and somewhat elongated elements1 constituting the cortex4 ,the specimen drawn in fig4 #aje1 ,a1 shows very prominent grooves in the cortex opposite the middle of each bay of the primary wood4 ,it is these grooves that give to the ordinary casts of ,sphenophyllum branches the appearance of longitudinal lines traversing each internode4 ,in a longitudinal section of a stem1 the cortical tissue 7fig4 #ajd1 c7 is found to be broader in the nodal regions1 thus giving rise to the tumid nodes referred to in the diagnosis4 ,the increased breadth at the nodes does not mean that the xylem is broader in these regions1 as it is in ,calamite stems4 ,small strands of vascular tissue are given off from the three edges of the triangular stele 7fig4 #aje ,a7 at each node2 these branch in passing through the cortex on their way to the verticils of leaves4 ,the space b in the diagrammatic section of fig4 #ajd was originally occupied by the phloem and inner cortex4 ,in some species of ,sphenophyllum the apex of each arm of the xylem strand1 as seen in transverse section1 is occupied by a longitudinal canal surrounded by spiral tracheids1 as in the primary xylem of the old stem shown in fig4 #aje1 ,c4 ,illustration3 ,,fig4 #aje4 ,sphenophyllum4 ,a4 ,transverse section of young stem4 ,b4 ,transverse section of the wood of a young stem2 px1 protoxylem2 x1 secondary xylem4 7,a and ,b4 ,sphenophyllum plurifoliatum47 #bj4 ,c4 ,transverse section of an old stem2 7,s4 insigne72 a1 phloem2 b1 periderm2 c1 fascicular secondary xylem2 d1 interfascicular secondary xylem4 #i4 7,no4 #iad in the ,williamson ,collection47 ,d4 ,longitudinal section of the reticulate tracheae and medullary rays2 r1 r1 r1 of ,s4 plurifoliatum4 #cf4 ,e4 ,similar section of ,s4 insigne4 #ge4 7,d and ,e after ,williamson and ,scott47 ii4 ,secondary structure4 ,with the exception of very young twigs the petrified ,sphenophyllum stems usually show a greater or less development of secondary wood4 ,in the xylem-strand of fig4 #aje1 ,b1 the broad concave bays of the primary wood have been filled in by the development of two rows of large secondary tracheids1 x1 but opposite the protoxylem groups1 px1 there are no signs of cambial activity4 ,in the unusually large stem represented by a rough sketch in fig4 #aje1 ,c1 the triangular primary xylem lies in the centre of a thick mass of secondary vascular tissue4 ,the secondary and primary wood together have a diameter of about #e mm4 ,after the bays between each protoxylem corner have been filled in1 the formation of secondary wood proceeds uniformly along the stem radii1 but the rows of tracheids and medullary rays which are developed opposite the corners of the primary strand1 c1 differ in certain characters from the broader masses of wood opposite the bays4 ,for convenience1 the secondary wood1 c1 opposite the protoxylem groups has been spoken of as fascicular wood1 and the rest1 d1 as interfascicular wood4 ,the secondary xylem consists either of tracheae with numerous bordered pits on their radial walls 7fig4 #aje1 ,d71 or of tracheae with broad and bordered scalariform pits 7fig4 #aje1 ,e74 ,the suggestion of concentric rings of growth in the wood in fig4 #aje1 ,c1 is rather deceptive2 there are no well-marked regular rings in ,sphenophyllum stems1 but irregular bands of smaller elements occasionally interrupt the uniformity of the secondary xylem4 ,in some stems the medullary rays have the form of rows of parenchymatous cells1 which in tangential longitudinal section are found to consist frequently of a single row of radially disposed elements2 this type of medullary rays occurs in the species ,sphenophyllum insigne1 in which the tracheae are scalariform4 ,three medullary rays1 r1 are seen on the radial face of the scalariform tracheids in fig4 #aje1 ,e1 which represents a radial section of this species4 ,in other species1 e4g4 ,s4 plurifoliatum1 the medullary rays have a peculiar and characteristic structure2 in a transverse section of the stem they appear as groups of a few parenchymatous cells in the spaces between the truncated angles of the large tracheae 7fig4 #ajf74 ,in longitudinal section these medullary-ray elements resemble thick bars stretching radially across the face of the tracheae 7fig4 #aje1 ,d1 r72 the apparent septa or bars are however thin-walled cells connecting the different groups of medullary-ray cells1 as seen in a transverse section4 ,these radial connecting cells are occasionally seen as short rays in transverse sections of stems4 ,the cambium and phloem elements are occasionally preserved in good specimens of older stems2 the former consist of tabular flatted thin-walled cells1 and the latter in some cases include large sieve-tubes and narrower parenchymatous elements4 ,the sections shown in fig4 #ajg1 ,e and ,f1 illustrate the preservation of cambial and phloem tissue4 ,in the transverse section of fig4 #ajg1 ,f1 the secondary xylem with the medullary rays1 r1 is succeeded by a few tabular cambium cells1 and external to these there are thin-walled elements of unequal size representing the phloem4 ,in fig4 #ajg1 ,e1 the scalariform tracheids are succeeded by narrow thin-walled cells1 and the larger elements with transverse and oblique septa are no doubt sieve-tubes4 ,in the large stem of fig4 #aje1 ,c1 the xylem is succeeded by a band of tissue1 a1 which is no doubt phloem1 and external to this there is a considerable development of periderm 7b74 ,the periderm in ,sphenophyllum stems had a deep-seated origin1 the phellogen or cork-cambium occasionally being formed in the secondary phloem-parenchyma1 and in other cases in the pericycle1 as in the stems of some living dicotyledons4 ,williamson and ,scott#hgb describe stems in which a succession of phellogens were formed at different levels1 thus producing a scaly type of bark1 such as we find in the ,pine or the ,plane tree4 ,sidenote3 ,,sphenophyllum ,,plurifoliatum4 ,before describing the structure of the strobili of ,sphenophyllum1 we may briefly point out the distinguishing features of two specific types of the genus recently described by ,williamson and ,scott4 ,one of these species1 ,s4 insigne1 was originally described by ,williamson as an ,asterophyllites2 the numerous narrow linear leaves in each verticil led to the inclusion of the specimens in the latter genus4 ,the material on which this species is founded is from the volcanic beds of ,pettycur1 ,burntisland1 on the coast of the ,firth of ,forth4 #a4 ,sphenophyllum insigne 7,will474 ,figs4 #aje1 ,c and ,e1 and #ajg1 ,e and ,f4 #ahia4 ,asterophyllites insignis4 ,williamson#hgc4 ,an intercellular space occurs at each angle of the three-rayed primary xylem strand1 and spiral tracheae are abundant4 ,the tracheae of the secondary wood have scalariform markings on the radial walls4 ,regular medullary rays extend through the secondary wood4 ,the phloem contains large sieve-tubes4 ,this species occurs in the ,calciferous sandstone rocks of ,burntisland1 and has lately been recorded from ,germany4 ,it characterises a lower horizon than ,s4 plurifoliatum 7,will4 and ,scott74 #b4 ,sphenophyllum plurifoliatum 7,williamson and ,scott7#hgd4 ,figs4 #aje1 ,a1 ,b1 and ,d1 and #ajf4 #ahia4 ,asterophyllites sphenophylloides4 ,will4#hge ,the specific name plurifoliatum was proposed by ,williamson and ,scott for a type of stem originally described by ,williamson#hgf as an ,asterophyllites1 from the ,coal-,measures of ,oldham1 ,lancashire4 ,this form of stem has not so far been connected with any of the older species founded on external characters1 but it evidently bore foliage in which the leaves were deeply divided1 as in ,sphenophyllum trichomatosum 7fig4 #aaj1 ,b74 ,illustration3 ,,fig4 #ajf4 ,sphenophyllum plurifoliatum1 ,will4 and ,scott4 ,from a photograph by ,mr ,highly from a section in the ,williamson ,collection 7no4 #hii74 #bg4 ,in this species there are no canals at the angles of the primary xylem1 and there are fewer spiral tracheae than in ,s4 insigne4 ,the tracheae of the secondary wood have numerous small pits on the radial walls1 and the medullary rays are chiefly composed of parenchymatous cells1 which appear in transverse section as groups of cells between the truncated angles of the tracheae4 ,the characters are fairly well seen in the xylem portion of a stele shown in fig4 #ajf4 ,the fascicular wood includes some rows of parenchymatous medullary-ray cells in addition to the characteristic groups1 as seen in the figure4 ,a slightly oblique transverse section of a stem is often convenient in the interpretation of histological features2 one of the sections of ,s4 plurifoliatum in the ,williamson collection 7no4 #hic71 which has been cut somewhat obliquely1 shows very clearly the differences in pitting exhibited by the different xylem elements4 b4 ,roots4 ,our knowledge of the anatomy of ,sphenophyllum roots is very limited4 ,renault has described a somewhat imperfect example of a silicified root from ,st4 tienne and ,autun4 ,the drawing in fig4 #ajg1 ,b1 which is copied from one of ,renault's figures1 shows a cylindrical mass of xylem with a small band of narrower elements occupying the centre1 and surrounded by rows of larger secondary tracheae4 ,the central bipolar band is described as the diarch primary xylem1 around which the secondary pitted elements have been developed4 ,it is probable that the specimen described by ,renault is a root of ,sphenophyllum1 but my impression gained from an examination of the section was that the diarch primary strand is not quite so clear as in the published figures4 ,until we possess better material we cannot attempt any very satisfactory description of the anatomical features of the roots of this genus4 ,a section of a ,sphenophyllum stem has been figured by ,felix#hgg1 in which a lateral member is being given off2 this may possibly represent the origin of an adventitious root1 but the preservation is not sufficiently distinct to render this certain4 c4 ,leaves4 ,renault#hgh has described some silicified leaves of ,sphenophyllum from ,autun in which the laminae consist of thin-walled loose parenchyma1 traversed by small groups of tracheids constituting the simple or forked veins4 ,the epidermis is made up of a single layer of cells1 with here and there indistinct indications of stomata4 ,a more perfect stoma has1 however1 been described by ,solms-,laubach from the epidermis of a bract in a strobilus 7fig4 #ajg1 ,a74 ,illustration3 ,,fig4 #ajg4 ,a4 ,stoma in a bract of ,sphenophyllostachys4 ,b4 ,root of ,sphenophyllum4 ,c4 ,sphenophyllostachys ,rmeri1 ,solms4 s1 sporangiophore1 b1 bract4 ,d4 ,sporangium4 ,e and ,f4 ,sections through the cambium1 phloem and secondary xylem of ,sphenophyllum insigne 7,will474 s1 sieve-tube4 ,g4 ,sporangium and pedicel4 ,a1 ,c1 ,d4 ,after ,solms-,laubach4 ,b4 ,after ,renault4 ,e-,g4 ,after ,williamson and ,scott4 ,e4 ,f4 #ajj4 ,g4 #aae4 d4 ,cones4 ,the history of the recognition of the cones of ,sphenophyllum has already been briefly alluded to in chapter ,v41 p4 #ajj4 ,the main points in the structure of the cones of this genus were known for several years1 before the fact was established that they belonged to ,sphenophyllum stems4 ,in #ahga ,williamson#hgi published an account of an imperfect fossil strobilus from the ,lower ,coal-,measures of ,oldham1 ,lancashire1 under the name of ,volkmannia ,dawsoni4 ,the generic term ,volkmannia has been used by different writers for cones varying considerably in structural features2 in the case of ,williamson's fossil1 ,weiss#hhj substituted the name ,bowmanites1 a genus instituted by ,binney#hha for a strobilus apparently of the same type as ,volkmannia ,dawsoni4 ,in #ahia ,williamson#hhb described some additional specimens of ,bowmanites ,dawsoni1 and1 as in his earlier paper1 he compared the strobilus with ,asterophyllites and ,sphenophyllum1 but it was still a matter of speculation as to what was the form of the vegetative branches4 ,soon after the more complete account of the ,english cones was published1 ,zeiller#hhc recognised a close agreement between some ,french and ,belgian specimens of ,sphenophyllum strobili and the strobilus described by ,williamson4 ,a closer comparison thoroughly established the connection between ,bowmanites ,dawsoni and ,sphenophyllum2 and there is little doubt that this strobilus belongs to the stem known as ,sphenophyllum cuneifolium 7,sternb47--a well-known species of the genus4 ,sidenote3 ,,strobilus4 ,the most important morphological features of the strobilus of ,sphenophyllum may best be illustrated by a detailed account of one specific type1 and by a brief reference to other forms which are characterised by certain differences in the number and attachment of the sporangia4 ,when we know that a given strobilus must have grown on a ,sphenophyllum stem1 the obvious name to assign to it would seem to be that of the plant which bore it2 but there are advantages in making use of special generic terms for detached cones1 which cannot be referred with certainty to a particular species of stem4 ,the genus ,calamostachys affords an example of a name which is intended to denote that a cone so called belongs to a ,calamarian plant2 similarly such a name as ,sphenophyllostachys may be used for ,sphenophylloid cones which cannot be connected with certainty to particular species of ,sphenophyllum4 ,it has been suggested that the genus ,bowmanites1 first used for a cone which was afterwards recognised as belonging to a ,sphenophyllum1 should be employed instead of the sesquipedalian term ,sphenophyllostachys4 ,the latter is used here as being in accordance with a generally accepted and convenient system of nomenclature1 and as a name which at once denotes the fact that the fossil is not only a cone but that it belongs to a ,sphenophyllum4 ,sphenophyllostachys ,dawsoni 7,will474 ,figs4 #ajg1 ,a and ,g1 #ajh4 ,probably the strobilus of ,sphenophyllum cuneifolium 7,sternb474 ,illustration3 ,,fig4 #ajh4 ,diagrammatic longitudinal section of a ,sphenophyllum strobilus4 ,the upper figure represents a portion of a whorl of bracts4 7,the smaller figure1 after ,zeiller47 ,the cone consists of a central axis bearing a number of verticils of bracts coherent in their lower portions in the form of a widely open funnel-shaped disc1 which splits up peripherally into #ad-bj linear-lanceolate segments4 ,the free segments of each verticil have an obliquely ascending or almost vertical position1 and extend upwards for a distance of about six internodes4 ,the smaller drawing in fig4 #ajh shows the appearance in side view of the narrow bracts of a single whorl4 ,a transverse section of a strobilus would include1 therefore1 sections of several concentric series of ascending bracts4 ,the verticils of ,sphenophyllostachys ,dawsoni are probably superposed1 but this point has not been definitely settled4 ,from the upper surface of the coherent basal portion of each verticil1 there are given off twice as many sporangiophores as there are free segments1 and these are attached close to the line of junction of the axis of the cone and the funnel-shaped disc4 ,each sporangiophore has the form of a slender stalk which bends inwards at its distal end and bears a single sporangium 7cf4 fig4 #ajg1 ,d74 ,the sporangiophores given off from the same verticil of bracts vary in length4 ,all the sporangiophores are attached to the coherent bracts at the same distance from the axis of the cone2 but as the sporangia between each verticil of bracts are arranged in two or three concentric series1 it follows that the length of the sporangiophores varies considerably4 ,the diagrammatic longitudinal section of a strobilus in fig4 #ajh shows three concentric series of sporangia between successive bract-verticils4 ,a similar diagram was published by ,williamson in #ahibhhd1 and afterwards copied by ,potoni#hhe1 but in ,williamson's restoration the sporangiophores of the three series of sporangia are erroneously represented as arising from different points on the surface of the bracts4 ,there is little doubt1 as regards the strobilus of ,s4 cuneifolium1 that the sporangiophores were given off in a single series close to the axils of the bracts1 as is partially shown in fig4 #ajh4 ,the central part of the axis of the cone is occupied by a single triangular stele like that of the stem1 except that each ray of the xylem strand has a comparatively broad blunt termination1 and is not tapered to a narrow arm as in fig4 #aje1 ,a and ,b4 ,the wood consists of pitted tracheae1 with two groups of protoxylem elements at each of the truncated angles of the solid strand of xylem4 ,from the angles of the stele branches of vascular tissue pass out through the cortex to supply the sterile and fertile segments of each verticil4 ,one of the transverse sections of the ,sphenophyllum cone in the ,british ,museum ,collection 7no4 #ahih ,e7 affords a good example of the misleading appearance occasionally presented by an intruded #8rootlet' of ,stigmaria2 the vascular tissue of the cone has disappeared1 and a ,stigmarian appendage with its vascular bundle occupies the position of the stelar tissues4 ,the bracts consist of parenchymatous tissue limited externally by an epidermis containing stomata4 ,a single stoma with subsidiary cells is represented in fig4 #ajg1 ,a4 ,the sporangiophores are composed internally of thin-walled cells with stronger cells towards the surface4 ,the longer sporangiophores in a series may be more or less coherent for part of their length to the upper surface of the verticil of bracts4 ,in fig4 #ajh the slender sporangiophores do not appear to come off always from the same portion of the bracts1 but this is due to some of them lying on the surface of the latter during part of their course to support the external circle of sporangia4 ,the hook-like distal end of a sporangiophore1 towards the point of attachment of the sporangium1 is characterised by the larger size and greater prominence of the surface cells2 these larger cells1 which pass over the upper surface of a sporangium base1 probably constitute a kind of annulus which determines the dehiscence of the sporangial wall#hhf4 ,fig4 #ajg1 ,g1 represents a sporangiophore and its sporangium cut through transversely just below the point of attachment of the latter to the end of the hook-like termination of the former4 ,the spores are characterised by an irregularly reticulate thickening of the outer coat or exospore1 as seen in the figure4 ,one of the chief points of interest suggested by a ,sphenophyllum cone is the exact morphological nature of the sporangiophores4 ,are they branches borne in the axils of bracts1 or may we regard each sporangiophore as a modified leaf1 which has become coherent with the whorls of sterile leaves8 ,or is a sporangiophore merely a stalk of a sporangium2 or a ventral lobe of a leaf1 of which the sterile bracts represent the dorsal lobes8 ,although it is impossible without the evidence of development to decide with certainty between these alternatives1 it would seem most probable that a sporangiophore may be looked upon as a ventral lobe of a leaf1 the sterile lobes forming the bracts or members of the sterile whorls of the cone4 ,this question is discussed by ,zeiller#hhg and ,williamson and ,scott#hhh1 also more recently by ,scott#hhi in his memoir on ,cheirostrobus4 ,sphenophyllostachys ,rmeri 7,solms-,laubach7#hij4 ,fig4 #ajg1 ,c and ,d4 ,in another type of ,sphenophyllum strobilus1 recently described by ,solms-,laubach1 the incurved end of each sporangiophore bore two sporangia4 ,in most respects this species1 which has not been found in connection with a vegetative shoot1 agrees with ,sphenophyllostachys ,dawsoni4 ,in fig4 #ajg1 ,c1 which is copied from one of ,solms-,laubach's drawings#hia1 we have an oblique transverse section of part of a strobilus1 including portions of two series of sporangia borne on one verticil of bracts1 and at the right-hand edge the section has passed through the sporangia belonging to another whorl of bracts4 ,there were probably three concentric series of sporangia attached to each verticil of bracts1 as in the case of fig4 #ajh4 ,the unshaded area1 b 7fig4 #ajg1 ,c71 represents the bracts of two successive sterile whorls in transverse section4 ,the shaded areas are the sporangia1 with their sporangiophores1 s4 ,the relative position of the sporangia and sporangiophores suggests that each pedicel bore two sporangia at its tip1 instead of one1 as in the strobilus of ,sphenophyllum cuneifolium 7,sternb474 ,a further variation in the structure of the strobili is illustrated by some specimens of ,s4 trichomatosum ,stur1 described by ,kidston#hib1 from the ,coal-,measures of ,barnsley4 ,each whorl of bracts bears a single series of oval sporangia which appear to be sessile on the basal portion of the whorl4 ,it is possible that delicate sporangiophores may have been present1 but in the imperfect examples in ,kidston's collection#hic the sporangia present the appearance of being seated directly on the surface of the bracts4 ,as the specimens do not show any internal structure1 it would be unwise to lay too much stress on the apparent absence of the characteristic sporangiophores4 ,in any case1 ,kidston's cones afford an illustration of the occurrence of a single series of sporangia in each whorl1 instead of the pluriseriate manner of occurrence in some other species4 ,the statement is occasionally met with that some ,sphenophyllum cones possessed two kinds of spores1 but we are still in want of satisfactory evidence that this was really the case4 ,renault has described an imperfect specimen1 which he considers points to the heterosporous nature of a ,sphenophyllum cone1 but ,zeiller and ,williamson and ,scott have expressed doubts as to the correctness of ,renault's conclusions4 ,while admitting the possibility of undoubted heterosporous strobili being discovered1 we are not in a position to refer to ,sphenophyllum as having borne strobili containing two kinds of spores#hid4 ,sidenote3 ,,sphenophyllum ,,emarginatum4 ,the following are some of the specimens in the ,williamson ,cabinet which illustrate the structure of ,sphenophyllum3-- ,s4 plurifoliatum4 #hgd1 #hhb1 #hhd1 #hic1 #hid1 #hig1 #hii1 #ija1 #ijc1 #ijh1 #ahic4 ,s4 insigne4 #iaj1 #iad1 #iai1 #iba1 #ibb1 #ibd1 #ibf1 #adbj1 #ahih4 ,sphenophyllostachys4 #ajdi;,a-#ajdi;,c1 #ahih4 ,b4 ,types of vegetative branches of ,sphenophyllum4 #a4 ,sphenophyllum emarginatum 7,brongniart74 ,fig4 #aji4 #ahbb4 ,sphenophyllites emarginatus1 ,brongniart#hie4 #ahbh4 ,sphenophyllum emarginatum1 ,brongniart#hif4 #ahbh4 ,sphenophyllum truncatum1 ,brongniart#hif4 #ahbh4 ,rotularia marsileaefolia1 ,bischoff#hig4 #ahfb4 ,sphenophyllum osnabrugense1 ,rmer#hih4 ,illustration3 ,,fig4 #aji4 ,sphenophyllum emarginatum 7,brongniart74 ,from a specimen in the ,collection of ,mr ,r4 ,kidston1 ,upper ,coal-,measures1 ,radstock4 nat4 size4 ,this species of ,sphenophyllum bears verticils of six or eight wedge-shaped leaves varying in breadth and in the extent of dissection of the laminae2 they are truncated distally1 and terminate in a margin characterised by blunt or obtusely-rounded teeth1 each of which receives a single vein4 ,the larger leaves are usually more or less deeply divided by a median slit4 ,the narrow base of each leaf receives a single vein which branches repeatedly in a dichotomous manner in the substance of the lamina4 ,several drawings have been given by ,sterzel#hii in a memoir on ,permian plants1 showing the variation in leaf-form in ,sphenophyllum emarginatum1 but as ,kidston#ijj and ,zeiller#ija have pointed out ,sterzel's specimens probably belong to ,s4 cuneifolium 7,sternb474 ,branches are given off singly from the nodes1 and the cones are borne at the tips of branches or branchlets4 ,the cone of ,s4 emarginatum agrees very closely with that of ,s4 cuneifolium1 and is of the same type as that shown in fig4 #ajh4 ,the small branch of ,s4 emarginatum represented in fig4 #aji does not show clearly the detailed characters of the species1 as the leaf-margins are not well preserved4 ,in one of the largest specimens of this species which ,i have seen1 in the ,leipzig ,museum1 the main stem has internodes of about #ci cm4 in length1 from which a lateral branch with much shorter internodes is given off from a node4 ,it is important to notice the close resemblance1 as pointed out by ,zeiller1 between some of the narrower-leaved forms of ,s4 emarginatum and ,s4 cuneifolium 7,sternb47#ijb2 but in the latter species the margins of the leaves have sharp1 and not blunt teeth4 ,the cone described and figured by ,weiss#ijc as ,bowmanites germanicus1 since investigated by ,solms-,laubach#ijd1 must be referred to this species4 ,geinitz#ije figured a cone in #ahee as that of ,s4 emarginatum1 but his determination of the species is a little doubtful4 ,good figures of the true cone of ,s4 emarginatum have been given by ,zeiller#ijf in his ,flore de ,valenciennes1 as well as in his important memoir on the fructification of ,sphenophyllum4 ,sidenote3 ,,leaves4 #b4 ,sphenophyllum trichomatosum ,stur4 ,fig4 #aaj1 ,b4 ,the finely-divided leaves of the single whorl shown in fig4 #aaj1 ,b 7from the ,middle ,coal-,measures of ,barnsley1 ,yorkshire71 afford an example of a form of ,sphenophyllum which is represented by such species as ,s4 tenerrimum ,ett4#ijg1 ,s4 trichomatosum ,stur#ijh1 and ,s4 myriophyllum#iji ,crp4 ,probably the specimen should be referred to ,s4 trichomatosum1 but it is almost impossible to speak with certainty as to the specific value of an isolated leaf-whorl of this form4 ,it has long been known that the leaves of ,sphenophyllum may vary considerably1 as regards the size of the segments1 on the same plant2 and the occurrence of such finely-divided leaves has lent support to an opinion which was formerly held by some writers1 that ,asterophyllites and ,sphenophyllum could not be regarded as well-defined separate genera4 ,this heterophylly of ,sphenophyllum has thus been responsible for certain mistaken opinions both as to the relation of the genus to ,calamocladus#iaj 7,asterophyllites71 and as regards the view that the finely-divided laminae belonged to submerged leaf-whorls1 while the broader segments were those of floating or subaerial whorls4 ,there is a very close resemblance between some of the deeply-cut and linear segments of a ,sphenophyllum and the leaves of ,calamocladus1 but in the former genus the linear segments are found to be connected basally into a narrow common sheath4 ,the assertion#iaa that the deeply-cut leaves occur on the lower portions of stems is not supported by the facts4 ,kidston#iab has pointed out that the cones are often borne on branches with such leaves1 and the same author refers to a figure by ,germar1 in which entire and much-divided leaves occur mixed together in the same individual specimen4 ,m4 ,zeiller recently pointed out to me a similar irregular association of broader and narrower leaf-segments on the same shoots in some large specimens in the cole des ,mines1 ,paris4 ,cones of ,sphenophyllum tenerrimum have been figured by ,stur#iac and others2 they are characterised by their small size and by the dissection of the slender free portions of the narrow bracts#iad4 #c4 ,sphenophyllum ,thoni ,mahr4 ,fig4 #aaj1 ,a4 ,another type of ,sphenophyllum is illustrated by ,s4 ,thoni ,mahr as shown in fig4 #aaj1 ,a4 ,this species was first described by ,mahr#iae from the ,coal-,measures of ,ilmenau1 and has since been figured by ,zeiller and other authors4 ,each whorl consists of six large obcuneiform leaves with the broad margin somewhat irregularly fringed4 ,the unusually good specimen of which fig4 #aaj1 ,a1 represents a single verticil was originally described and figured by ,zeiller in #ahhjiaf2 it is now in the cole des ,mines ,museum1 ,paris4 ,illustration3 ,,fig4 #aaj4 ,a4 ,sphenophyllum ,thoni1 ,mahr4 7,after ,zeiller47 ,b4 ,sphenophyllum trichomatosum1 ,stur4 ,from a specimen in the ,woodwardian ,museum2 from the ,coal-,measures of ,barnsley1 ,yorks4 ,a and ,b nat4 size4 ,the leaf-forms illustrated by figs4 #aji and #aaj are some of the more extreme types of ,sphenophyllum leaves2 but these are more or less connected by a series of intermediate forms4 ,for a more complete systematic account of the different species the student should consult such works as those by ,coemans and ,kickx#iag1 ,zeiller1 ,schimper1 and others4 #d4 ,sphenophyllum speciosum 7,royle74 ,fig4 #aaa4 #ahcd4 ,trizygia speciosa1 ,royle#iah4 ,the species shown in fig4 #aaa has been usually described as a separate genus ,trizygia1 a name instituted by ,royle in #ahcd for some ,indian fossils from the ,lower ,gondwana rocks of ,india#iai4 ,zeiller#ibj has lately pointed out the advisability of including this ,asiatic type in the genus ,sphenophyllum4 ,the slender stem bears verticils of cuneate leaves in three pairs at each node1 the anterior pair being smaller than the two lateral pairs4 ,the characteristic ,sphenophyllum venation is clearly seen in the enlarged leaf1 fig4 #aaa1 ,b4 ,illustration3 ,,fig4 #aaa4 ,sphenophyllum speciosum 7,royle74 ,a4 ,nat4 size4 ,b4 enlarged leaf4 ,from the ,raniganj ,coal-field1 ,india4 7,after ,feistmantel47 ,the inequality of the members of a single whorl1 which characterises this ,indian plant1 is sometimes met with in ,european species4 ,a specimen of ,sphenophyllum oblongifolium1 which ,prof4 ,zeiller showed me in illustration of this point1 was practically indistinguishable from ,trizygia#iba4 ,in some of the earlier descriptions of the ,indian species the generic name ,sphenophyllum#ibb was used by ,mc,clelland and others1 but the supposed difference in the leaf-whorls was made the ground of reverting to the distinct generic term ,trizygia4 ,now that a similar type of leaf-whorl is known to occur in ,sphenophyllum1 it is better to adopt that genus rather than to allow the question of locality to unduly influence the choice of a separate generic name for an ,indian plant4 ,sidenote3 ,,geological ,,range4 ,c4 ,affinities1 range and habit of ,sphenophyllum4 ,it has been pointed out in the description of ,sphenophyllum1 that the most widely separated families of recent plants have been selected by different authors as the nearest living allies of this ,palaeozoic genus4 ,it is now generally admitted that ,sphenophyllum is a generic type apart2 it cannot be classed in any family or sub-class of recent or fossil plants1 without considerably extending or modifying the recognised characteristics of existing divisions of the plant-kingdom4 ,the anatomical characters of the ,sphenophyllum stem are such as one finds in some recent genera of the ,lycopodineae1 especially ,psilotum4 ,if the stele of ,psilotum were composed internally of a solid strand of xylem1 we should have a close correspondence between the centripetally-developed wood of this genus and that of ,sphenophyllum4 ,similar comparisons might be drawn with other existing genera1 but the more detailed consideration of the affinities of the ,palaeozoic plant will be more easily dealt with after other members of the ,pteridophytes have been described4 ,the recent discovery of an entirely new type of ,carboniferous strobilus in rocks of ,calciferous sandstone age on the shores of the ,firth of ,forth has thrown new light on the position of ,sphenophyllum4 ,cheirostrobus ,pettycurensis1 the new cone which ,scott has described in an able memoir1 affords certain points of contact with ,sphenophyllum on the one hand and with ,calamites on the other4 ,this important question will be dealt with after we have given an account of ,cheirostrobus#ibc4 ,to put the matter shortly1 ,sphenophyllum agrees with some ,lycopodinous plants in its anatomical features2 with the ,equisetales it is connected by the verticillate disposition of the leaves1 and some of the forms of ,sphenophyllum strobili present features which also point to ,equisetinous affinities4 ,in his ,presidential address to the ,botanical ,section at the ,british ,association ,meeting of #ahif ,scott#ibd thus refers to the ,sphenophyllums3--8,we may hazard the guess that this interesting group may have been derived from some unknown form lying at the root of both ,calamites and ,lycopods4 ,the existence of the ,sphenophyllae certainly suggests the probability of a common origin for these two series40 ,the result of the subsequent investigation of the new cone ,cheirostrobus amply justifies this opinion as to the position of ,sphenophyllum4 ,it is probable that ,sphenophyllum lived during the ,devonian period1 but the unsatisfactory specimens on which ,dawson has founded a species of this age1 ,s4 antiquum#ibe1 can hardly be said to afford positive evidence of the ,pre-,carboniferous existence of the genus4 ,from the ,culm rocks and other strata older than the ,coal-,measures1 we have such species as ,s4 insigne 7,will471 ,sphenophyllostachys ,rmeri 7,solms-,laubach71 and ,sphenophyllum tenerrimum1 ,ett4#ibf while ,s4 emarginatum#e1 ,brongn4 occurs in the ,upper ,coal-,measures and in the ,transition rocks4 ,s4 cuneifolium#ibg 7,sternb47 has been recorded from the ,transition1 ,middle and ,lower ,coal-,measures4 ,sphenophyllum oblongifolium1 ,germ4#ibh1 is recorded from ,lower ,permian rocks1 as is also ,s4 ,thoni#ibi1 ,mahr4 ,the comparison which has naturally been drawn between ,sphenophyllum with its slender stems bearing occasionally dimorphic leaves1 and water-plants is not1 ,i believe1 supported by the facts of anatomy or external characters4 ,the entire and finely-dissected leaves do not exhibit that regularity of relative disposition which is characteristic of aquatic plants2 the two forms of leaves may occur indiscriminately on the same branch4 ,the well-developed and thick xylem is not in accordance with the anatomical features usually associated with water-plants4 ,it is true that in some living dicotyledons of the family ,leguminosae1 which inhabit swampy places1 the secondary xylem is represented by a thick mass of unlignified and thin-walled parenchyma1 as in the genus ,aeschynomene#icj1 from which the material of #8pith'-helmets is obtained2 but the wood of ,sphenophyllum was obviously thick-walled and thoroughly lignified4 ,it is not improbable that the long and slender stems of this plant may have grown like small lianas in the ,coal-,measure forests1 supporting themselves to a large extent on the stouter branches of ,calamites and other trees4 ,the anatomical structure of a ,sphenophyllum stem would seem to be in accord with the requirements of a climbing plant4 ,it has been shewn#ica that in recent climbing plants the tracheae and sieve-tubes are characterised by their large diameter1 a fact which may be correlated with the small diameter of climbing stems and the need for rapid transport of food material4 ,in ,sphenophyllum the tracheae of the xylem have a wide bore1 and in ,s4 insigne the phloem contains unusually wide sieve-tubes4 ,the central position of the stele is another feature which is not inconsistent with a climbing habit4 ,schwendener and others#icb have demonstrated that in climbing organs1 as in underground stems and roots1 there is a tendency towards a centripetal concentration of mechanical or strengthening tissue4 ,the axial xylem strand of ,sphenophyllum would afford an efficient resistance to the tension or pulling force which climbing stems encounter4 ,,list ,,of ,,works ,,referred ,,to ,,in ,,the ,,text4 ,adamson1 ,s4 ,a4 7#hh7 ,notes on a recent discovery of ,stigmaria ficoides at ,clayton1 ,yorkshire4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xliv4 p4 #cge1 #ahhh4 ,agassiz1 ,s4 7#hh7 ,three ,cruises of the ,u4 ,s4 ,coast and ,geodetic ,survey ,steamer 8,blake0 in the ,gulf of ,mexico1 in the ,caribbean ,sea1 and along the ,atlantic ,coast of the ,united ,states1 from #ahgg to #ahhj4 ,london1 #ahhh4 ,andrae1 ,k4 ,j4 7#ec7 ,fossile ,flora ,siebenbrgens und des ,banates4 ,abhand4 k4 k4 geol4 ,reichsanst4 ,bd4 ,,ii4 ,abth4 ,,iii4 ,no4 #d1 #ahec4 ,andrussow1 ,n4 7#hg7 ,eine fossile ,acetabularia als ,gestein-bildender ,organismus4 ,ann4 k4 k4 nat4 hist4 ,hofmuseum1 ,wien4 ,bd4 ,,ii4 ,heft ,,ii4 p4 #gg1 #ahhg4 d',archiac1 ,e4 ,j4 ,a4 7#dc7 ,description gologique du dpartement de l',aisne4 ,mm4 ,soc4 ,gol4 ,france1 vol4 ,v4 pt4 ,,ii4 p4 #abi1 #ahdc4 ,artis1 ,f4 ,t4 7#be7 ,antediluvian ,phytology4 ,london1 #ahbe4 ,baker1 ,j4 ,g4 7#hg7 ,handbook of the ,fern-,allies4 ,london1 #ahhg4 ,balfour1 ,j4 ,h4 7#gb7 ,palaeontological ,botany4 ,edinburgh1 #ahgb4 ,barber1 ,c4 ,a4 7#hi7 ,the ,structure of ,pachytheca4 ,annals ,bot4 vol4 ,,iii4 p4 #ada1 #ahhi4 ---- 7#ij7 ,the ,structure of ,pachytheca4 ,ibid4 vol4 ,v4 p4 #ade1 #ahij4 ---- 7#ib7 ,nematophycus ,storriei1 nov4 sp4 ,ibid4 vol4 ,,vi4 p4 #cbi1 #ahib4 ,barrois1 ,c4 7#hh7 ,note sur l'existence du genre ,oldhamia dans les ,pyrnes4 ,ann4 ,soc4 ,gol4 ,nord1 vol4 ,,xv4 p4 #aed1 #ahhh4 ,barton1 ,r4 7#agea7 ,lectures in ,natural ,philosophy4 ,dublin1 #agea4 ,bary1 ,a4 de4 7#hd7 ,comparative anatomy of the vegetative organs of the ,phanerogams and ,ferns4 ,oxford1 #ahhd4 ---- 7#hg7 ,lectures on ,bacteria4 ,oxford1 #ahhg4 ,bates1 ,h4 ,w4 7#fc7 ,the ,naturalist on the ,river ,amazons4 ,london1 #ahfc4 #b vols4 ,bateson1 ,w4 ,b4 7#hh7 ,suggestion that certain fossils known as ,bilobites may be regarded as casts of ,balanoglossus4 ,proc4 ,camb4 ,phil4 ,soc4 vol4 ,,vi4 p4 #bih1 #ahhh4 ,batters1 ,e4 ,a4 7#ij7 ,vide ,holmes1 ,e4 ,m4 ---- 7#ib7 ,on ,conchocelis1 a new genus of perforating ,algae4 ,phycological ,memoirs4 ,london1 p4 #be1 #ahib4 ,benecke1 ,e4 ,w4 7#gf7 ,geognostisch-palontologische ,beitrge4 ,vol4 ,,ii4 ,heft ,,iii41 #ahgf4 ,bennett1 ,j4 ,j4 and ,brown1 ,r4 7#ch74 ,plantae ,javanicae4 ,london1 #ahch-eb4 ,bentham1 ,g4 7#gj7 ,presidential ,address4 ,proc4 ,linn4 ,soc4 p4 lxxiv4 #ahfi-gj4 ,bertrand1 ,c4 ,e4 7#ic7 ,les ,bogheads ,algues4 ,bull4 ,soc4 ,belg4 ,gol4 ,palont4 ,hydrol4 vol4 ,,vii4 p4 #de1 #ahic4 ---- 7#if7 ,nouvelles remarques sur le ,kerosene ,shale de la ,nouvelle-,galles du ,sud4 ,soc4 d'hist4 nat4 ,autun1 #ahif4 ,bertrand1 ,c4 ,e4 and ,renault1 ,b4 7#ib7 ,pila bibractensis et le ,boghead d',autun4 ,soc4 d'hist4 nat4 ,autun41 #ahib4 ---- 7#id7 ,reinschia ,australia et premires remarques sur le ,kerosene ,shale de la ,nouvelle-,galles du ,sud4 ,soc4 d'hist4 nat4 ,autun1 #ahid4 ,binney1 ,e4 ,w4 7#fh7 ,observations on the ,structure of ,fossil plants found in the ,carboniferous ,strata4 ,pt4 ,i4 ,calamites and ,calamodendron4 ,palaeont4 ,soc4 ,london1 #ahfh4 ---- 7#ga7 ,ibid4 ,pt4 ,,ii4 ,lepidostrobus and some allied cones4 ,bischoff1 ,g4 ,w4 7#bh7 ,die cryptogamischen ,gewchse4 ,nrnberg1 #ahbh4 ,bornemann1 ,j4 ,g4 7#ef7 ber organische ,reste der ,lettenkohlen-,gruppe ,thringens4 ,leipzig1 #ahef4 ---- 7#hf7 ,geologische ,algenstudien4 ,jahrb4 ,k4 ,preuss4 ,geol4 ,landesanst4 ,bergakad41 #ahhf4 ---- 7#hg7 ,die ,versteinerungen des ,cambrischen ,schichtensystems der ,insel ,sardinien4 ,nova ,acta ,acad4 ,caes4 ,leop4 ,car4 vol4 ,,li41 #ahhg4 ---- 7#ia7 ,ibid4 vol4 ,,lvi41 #ahia4 ,bornet1 ,e4 and ,flahault4 7#hi7 ,note sur deux nouveaux genres d'algues perforantes4 ,journ4 ,bot4 vol4 ,,ii4 p4 #afa1 #ahhh4 ---- 7#hi7 ,sur quelques plantes vivant dans le test calcaire des mollusques4 ,bull4 ,soc4 ,bot4 ,france1 vol4 ,,xxxvi4 p4 clxvii41 #ahhi4 ,bower1 ,f4 ,o4 7#id7 ,studies in the morphology of ,spore-producing members4 ,equisetineae and ,lycopodineae4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxxxv4 ,b4 p4 #dgc1 #ahid4 ,brongniart1 ,a4 7#bb7 ,sur la classification et la distribution des vgtaux fossiles en gnral4 ,mm4 ,mus4 ,hist4 ,nat4 ,paris1 vol4 ,,viii4 p4 #bcc1 #ahbb4 ---- 7#bh7 ,prodrome d'une histoire des vgtaux fossiles4 ,paris1 #ahbh4 ---- 7#bh7 ,histoire des vgtaux fossiles4 ,paris1 #ahbh4 ---- 7#ci7 ,observations sur la structure intrieure du ,sigillaria elegans4 ,arch4 ,mus4 d'hist4 nat4 vol4 ,i4 p4 #dje1 #ahci4 ---- 7#di7 ,tableau des genres de vgtaux fossiles4 ,extrait du ,dictionnaire d'histoire naturelle1 vol4 ,,xiii4 p4 #di4 ,paris1 #ahdi4 ,brown1 ,a4 7#id7 ,on the structure and affinities of the genus ,solenopora4 ,geol4 ,mag4 #d vol4 ,i4 p4 #ade1 #ahid4 ,brown1 ,r4 7#aa7 ,some observations on the parts of fructification in ,mosses1 with characters and descriptions of two new genera of that order4 ,trans4 ,linn4 ,soc4 vol4 ,x4 p4 #cab1 #ahaa4 ---- 7#ch7 ,vide ,bennett1 ,j4 ,j4 ,bryce1 ,j4 7#gb7 ,the ,geology of ,arran4 ,glasgow and ,london1 #ahgb4 ,buckland1 ,w4 7#cg7 ,geology and ,mineralogy considered with reference to ,natural ,theology4 ,london1 #aheh4 ,buckman1 ,j4 7#ej7 ,on some fossil plants from the ,lower ,lias4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,vi4 p4 #dac1 #ahej4 ,bunbury1 ,c4 ,j4 ,f4 7#ea7 ,on some fossil plants from the ,jurassic ,strata of the ,yorkshire ,coast4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,vii4 p4 #agi1 #ahea4 ---- 7#fa7 ,notes on a collection of fossil plants from ,ngpur1 ,central ,india4 ,ibid4 vol4 ,,xvii4 p4 #cbe1 #ahfa4 ---- 7#hc7 ,botanical ,fragments4 ,london1 #ahhc4 ,btschli1 ,o4 7#hc7 ,bronn's ,klassen und ,ordnungen des ,thier-,reichs1 vol4 ,i4 ,leipzig and ,heidelberg1 #ahhc-hg4 ,campbell1 ,d4 7#ie7 ,the structure and development of the ,mosses and ,ferns4 ,london1 #ahie4 ,carpenter1 ,w4 ,b41 ,parker1 ,w4 ,k4 and ,jones1 ,t4 ,r4 7#fb7 ,introduction to the study of the ,foraminifera4 7,ray ,society7 ,london1 #ahfb4 ,carruthers1 ,w4 7#fg7 ,on the structure of the fruit of ,calamites4 ,journ4 ,bot4 ,vol4 ,v4 #ahfg4 ---- 7#gj7 ,on the structure of a ,fern stem from the ,lower ,eocene of ,herne ,bay4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xxvi4 p4 #cdi1 #ahgj4 ---- 7#ga7 ,on some supposed vegetable fossils4 ,ibid4 vol4 ,,xxvii4 p #ddc1 #ahga4 ---- 7#gb7 ,on the history1 histological structure1 and affinities of ,nematophycus ,logani1 ,carr4 7,prototaxites ,logani1 ,dawson71 an alga of ,devonian age4 ,micros4 ,journ4 vol4 ,,viii4 p4 #afj1 #ahgb4 ---- 7#gb7 ,vide ,woodward1 ,h41 p4 #afh4 -- 7#gf7 ,address before the ,geologists' ,association1 #ahgf-gg4 ,proc4 ,geol4 ,assoc4 vol4 ,v4 p4 #ag1 #ahgf4 ,cash1 ,w4 and ,hick1 ,t4 7#gh7 ,a contribution to the flora of the ,lower ,coal-,measures of the ,parish of ,halifax1 ,yorkshire4 ,proc4 ,yorks4 ,geol4 ,polyt4 ,soc4 vol4 ,,vii4 p4 #gc1 #ahgh-ha4 ---- 7#gh7 ,on fossil fungi from the ,lower ,coal-,measures of ,halifax4 ,proc4 ,yorks4 ,geol4 ,polyt4 ,soc4 vol4 ,,vii4 p4 #aae1 #ahgh4 ---- 7#ha7 ,a contribution to the flora of the ,lower ,coal-,measures of the ,parish of ,halifax1 ,yorkshire4 ,pt4 ,,iii4 ,proc4 ,yorks4 ,geol4 ,polyt4 ,soc4 vol4 ,,vii4 p4 #djj1 #ahha4 ,castracane1 ,f4 7#gf7 ,die ,diatomeen in der ,kohlenperiode4 ,pringsheim's ,jahrb4 vol4 ,x4 p4 #a1 #ahgf4 ,cayeux1 ,l4 7#ib7 ,sur la prsence de nombreuses ,diatomes dans les gaizes crtaces du bassin de ,paris4 ,compt4 ,rend4 vol4 ,,cxiv4 p4 #cge1 #ahib4 ---- 7#ig7 ,contribution l'tude micrographique des terrains sdimentaires4 ,mm4 ,soc4 ,gol4 ,nord1 vol4 ,,iv4 ii4 ,lille1 #ahig4 8,challenger40 ,reports on the ,scientific results of the ,voyage of ,h4,m4,s4 8,challenger0 during the years #ahgc-gf1 under the command of ,captain ,nares and ,captain ,thomson4 ,prepared under the ,superintendence of ,sir ,c4 ,wyville ,thomson and ,john ,murray4 ,london1 #ahhj-ie4 ---- 7#he7 ,narrative1 vols4 ,i4 and ,,ii4 #ahhb-he4 ---- 7#ia7 ,deep ,sea ,deposits4 ,j4 ,murray and ,a4 ,f4 ,renard1 #ahia4 ,christison1 ,r4 7#gf7 ,notice of ,fossil trees recently discovered in ,craigleith ,quarry near ,edinburgh4 ,phil4 ,trans4 ,edinburgh1 vol4 ,,xxvii4 p4 #bjc1 #ahgf4 ,church1 ,a4 ,h4 7#ie7 ,the structure of the ,thallus of ,neomeris dumetosa1 ,lam4 ,annals ,bot4 vol4 ,,ix4 p4 #eha1 #ahie4 ,coemans1 ,e4 and ,kickx1 ,j4 ,j4 7#fd7 ,monographie des ,sphenophyllum d',europe4 ,bull4 ,acad4 ,roy4 ,belg4 vol4 ,,xviii4 #b p4 #afj1 #ahfd4 ,cohn1 ,f4 7#fb7 ber die ,algen des ,carlsbader ,sprudels und deren ,antheil an der ,bildung des ,sprudel-,sinters4 ,abh4 ,schles4 ,ges4 vaterland4 ,cultur1 #ahfb1 p4 #fe4 ,cole1 ,g4 7#id7 ,on some examples of cone-in-cone structure4 ,mineral4 ,journ4 vol4 ,x4 #ahid4 ,comstock1 ,t4 ,h4 7#hh7 ,an introduction to ,entomology4 ,ithaca1 #ahhh4 ,conwentz1 ,h4 7#gh7 ber ein tertires ,vorkommen ,cypressenartiger ,hlzer bei ,calistoga in ,californien4 ,neues ,jahrb4 p4 #hjj1 #ahgh4 ---- 7#hj7 ,die fossilen ,hlzer von ,karlsdorf am ,zobten4 #ahhj4 ---- 7#ij7 ,monographie der baltischen ,bernsteinbume4 ,danzig1 #ahij4 ---- 7#if7 ,on ,english ,amber and ,amber generally4 ,nat4 ,science1 vol4 ,,ix4 p4 #ii1 #ahif4 ,corda1 ,a4 ,j4 7#de7 ,beitrge zur ,flora der ,vorwelt4 ,prag1 #ahde4 7,new edition1 unaltered1 #ahfg47 ,cormack1 ,b4 ,g4 7#ic7 ,on a cambial development in ,equisetum4 ,annals ,bot4 vol4 ,,vii4 p4 #fc1 #ahic4 ,costa1 ,mendes da4 7#ageh7 ,an account of the impressions of plants on the slates of coal4 ,phil4 ,trans4 ,r4 ,s4 ,london1 vol4 ,l4 p4 #bbh1 #ageh4 ,cotta1 ,c4 ,b4 7#ej7 ,die ,dendrolithen in ,beziehung auf ihren inneren ,bau4 ,dresden1 #ahej4 7,original edition1 #ahcb47 ,cramer1 ,c4 7#hg7 ber die verticillaten ,siphoneen1 besonders ,neomeris und ,cymopolia4 ,denksch4 ,schweiz4 ,nat4 ,ges4 vol4 ,,xxv4 #ahhg4 ---- 7#ij7 ber die verticillaten ,siphoneen1 besonders ,neomeris und ,bornetella4 ,denksch4 ,schweiz4 ,nat4 ,ges4 vol4 ,,xxxii4 #ahij4 ,credner1 ,h4 7#hg7 ,elemente der ,geologie4 ,leipzig1 #ahhg4 ,crpin1 ,f4 7#ha7 ,l'emploi de la ,photographie pour la reproduction des empreintes vgtales4 ,bull4 ,soc4 ,bot4 ,belg4 vol4 ,,xx4 pt4 ,,ii4 #ahha4 ,damon1 ,r4 7#hh7 ,a supplement to the geology of ,weymouth and the ,isle of ,portland4 ,weymouth1 #ahhh4 ,darwin1 ,c4 7#hb7 ,the ,origin of ,species4 7,edit4 #f47 ,london1 #ahhb4 ---- 7#hg7 ,the life and letters of ,charles ,darwin4 ,edited by ,francis ,darwin4 ,london1 #ahhg4 7,edit4 #b47 ---- 7#ij7 ,a ,naturalist's ,voyage4 ,london1 #ahij4 ,dawson1 ,j4 ,w4 7#ei7 ,on fossil plants from the ,devonian rocks of ,canada4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xv4 p4 #dgg1 #ahei4 ---- 7#ff7 ,on the conditions of the deposition of coal4 ,ibid4 vol4 ,,xxii4 p4 #ie1 #ahff4 ---- 7#ga7 ,the fossil plants of the ,devonian and ,upper ,silurian formations of ,canada4 ,geol4 ,surv4 ,canada1 #ahga4 ---- 7#ha7 ,notes on new ,erian 7,devonian7 plants4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xxxvii4 p4 #bii1 #ahha4 ---- 7#hb7 ,notes on ,prototaxites and ,pachytheca discovered by ,dr ,hicks in the ,denbighshire ,grits of ,corwen1 ,north ,wales4 ,ibid4 vol4 ,,xxxviii4 p4 #ajc1 #ahhb4 ---- 7#hh7 ,the geological history of plants4 ,london1 #ahhh4 ---- 7#ij7 ,on burrows and tracks of invertebrate animals in ,palaeozoic rocks4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xlvi4 p4 #eie1 #ahij4 ,deecke1 ,w4 7#hc7 ber einige neue ,siphoneen4 ,neues ,jahrb4 ,jahrg4 ,i4 p4 #a1 #ahhc4 ,defrance4 7#bf7 ,dictionnaire des ,sciences naturelles4 ,article ,polytrype1 vol4 ,,xlii4 p4 #dec1 #ahbf4 ,delgado1 ,j4 ,f4 ,n4 7#hf7 tude sur les ,bilobites4 ,secc4 ,trav4 ,gol4 ,portugal4 ,lisbon1 #ahhf4 ,dixon1 ,h4 ,h4 and ,joly1 ,j4 7#ig7 ,coccoliths in our coastal waters4 ,nature1 vol4 ,,lvi4 p4 #dfh1 #ahig4 ,dixon1 ,h4 ,n4 and ,jameson1 ,h4 ,g4 7#if7 ,the ,student's ,handbook of ,british ,mosses4 ,london1 #ahif4 ,duncan1 ,p4 ,m4 7#gf7 ,on some unicellular algae parasitic within ,silurian and ,tertiary ,corals1 with a notice of their presence in ,calceolina sandalina and other fossils4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xxxii4 p4 #bje1 #ahgf4 ---- 7#gf7 ,on some ,thallophytes parasitic within recent ,madreporaria4 ,proc4 ,r4 ,soc4 vol4 ,,xxv4 p4 #bch1 #ahgf4 ,dunker1 ,w4 7#df7 ,monographie der norddeutschen ,wealdenbildung4 ,braunschweig1 #ahdf4 ,duval-,jouve1 ,j4 7#fd7 ,histoire naturelle des ,equisetum de ,france4 ,paris1 #ahfd4 ,ehrenberg1 ,c4 ,g4 7#cf7 ber das ,massenverhltniss der jetzt lebenden ,kieselfusorien und ber ein neues ,infusiorien-,conglomerat als ,polirschiefer von ,jastrabo in ,ungarn4 ,abh4 k4 ,akad4 ,wiss4 ,berlin1 #ahcf1 p4 #aji4 ---- 7#ed7 ,mikrogeologie4 ,leipzig1 #ahed4 ,ellis1 ,j4 7#agee7 ,an essay towards a ,natural ,history of the ,corallines4 ,london1 #agee4 ,engelhardt1 ,h4 7#hg7 ber ,rosselinia conjugata 7,beck47 eine neue ,pilzart aus der ,braunkohlen-formation ,sachsens4 ,ges4 ,isis4 ,dresden1 ,abh4 #d1 p4 #cc1 #ahhg4 ,etheridge1 ,r4 7#ha7 ,vide ,hicks1 ,h4 ,etheridge1 ,r4 junr4 7#ib7 ,on the occurrence of microscopic fungi1 allied to the genus ,palaeachyla1 ,duncan1 in the ,permo-,carboniferous rocks of ,new ,south ,wales and ,queensland4 ,rec4 ,geol4 ,surv4 ,n4,s4,w4 ,pt4 ,,iii4 p4 #ie1 #ahib4 ---- 7#ie7 ,on the occurrence of a plant in the ,newcastle or ,upper ,coal-,measures possessing characters both of the genera ,phyllotheca ,brongn4 and ,cingularia ,weiss4 ,ibid4 vol4 ,,iv4 ,pt4 ,,iv4 p4 #adh1 #ahie4 ,ettingshausen1 ,c4 von4 7#ee7 ,die ,steinkohlenflora von ,radnitz in ,bhmen4 ,abhand4 k4 k4 geol4 ,reichsanst4 ,wien1 vol4 ,,ii4 p4 #a1 #ahee4 ---- 7#ff7 ,die fossile ,flora des ,mhrisch-,schlesischen ,dachschiefers4 ,ibid4 vol4 ,,xxv4 p4 #gg1 #ahff4 ,ettingshausen1 ,c4 von and ,gardner1 ,j4 ,s4 7#gi7 ,a monograph of the ,british ,eocene ,flora4 ,palaeontographical ,society4 ,london1 #ahgi-ahhb4 ,feilden1 ,h4 ,w4 7#if7 ,note on the glacial ,geology of ,arctic ,europe and its islands4 ,pt4 ,i4 ,kolguev ,island4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,lii4 p4 #eb1 #ahif4 ,appendix by ,a4 ,c4 ,seward1 p4 #fa4 ,feistmantel1 ,o4 7#gc7 ,das ,kohlenvorkommen bei ,rothwaltersdorf in der ,grafschaft ,glatz und dessen organische ,einschlsse4 ,zeit4 ,deutsch4 ,geol4 ,ges4 vol4 ,,xxv4 p4 #dfc1 #ahgc4 ---- 7#ge7 ,die ,versteinerungen der bhmischen ,kohlenablagerungen4 ,palaeontograph4 vol4 ,,xxiii4 p4 #a1 #ahge-gf4 ---- 7#ha7 ,the ,fossil ,flora of the ,gondwana ,system4 ,mem4 ,geol4 ,surv4 ,india1 7,ser4 ,,xii47 vol4 ,,iii4 #ahha4 7,the ,flora of the ,damuda-,panchet ,divisions1 pp4 #a-gg4 ,pls4 ,i4 ,a-,,xvi4 ,a bis1 #ahhj47 ---- 7#ij7 ,geological and palaeontological relations of the ,coal and plant-bearing beds of ,palaeozoic and ,mesozoic age in ,eastern ,australia and ,tasmania4 ,mem4 ,geol4 ,surv4 ,n4 ,s4 ,wales4 ,palaeontology1 ,no4 #c1 #ahij4 ,felix1 ,j4 7#hf7 ,untersuchungen ber den inneren ,bau westflischer ,carbon-,pflanzen4 ,abh4 ,geol4 ,landesanst4 #ahhf1 p4 #aec4 ---- 7#id7 ,studien ber fossile ,pilze4 ,zeit4 deutsch4 geol4 ,ges4 ,heft ,i4 p4 #bfi1 #ahid4 ---- 7#if7 ,untersuchungen ber den inneren ,bau westflischer ,carbon-pflanzen4 ,fldtani ,kzlny1 vol4 ,,xxvi4 p4 #afe1 #ahif4 ,fischer1 ,a4 7#ib7 ,die ,pilze4 ,rabenhorst's ,kryptogamen ,flora1 vol4 ,i4 ,abt4 ,,iv4 ,leipzig1 #ahib4 ,fliche1 ,p4 and ,bleicher1 --4 tude sur la flore de l'oolithe infrieure aux environs de ,nancy4 ,bull4 ,soc4 ,sci4 ,nancy1 vol4 ,v4 #b p4 #ed1 #ahha4 ,forbes1 ,e4 7#ef7 ,on the ,tertiary fluviomarine formation of the ,isle of ,wight4 ,mem4 ,geol4 ,surv4 #ahef4 ,forbes1 ,h4 ,o4 7#he7 ,a ,naturalist's ,wanderings in the ,eastern ,archipelago4 ,london1 #ahhe4 ,frh1 ,j4 7#ij7 ,zur ,kenntniss der gesteinbildenden ,algen4 ,abh4 ,schweiz4 pal4 ,ges4 vol4 ,,xviii4 #ahij4 ,fuchs1 ,t4 7#id7 ber eine fossile ,halimeda aus dem ,eocnen ,sandstein von ,greifenstein4 ,sitzbericht4 ,abh4 ,wien1 vol4 ,,ciii4 ,abt4 ,i4 p4 #cjj1 #ahid4 ---- 7#ie7 ,studien ber ,fucoiden und ,hieroglyphen4 ,denksch4 ,akad4 ,wien1 vol4 ,,lxii4 p4 #cfi1 #ahie4 ,gardner1 ,j4 ,s4 7#gi7 ,vide ,ettingshausen4 ---- 7#hd7 ,fossil plants4 ,proc4 ,geol4 ,assoc4 vol4 ,,viii4 p4 #bii1 #ahhd4 ---- 7#hf7 ,on ,mesozoic ,angiosperms4 ,geol4 ,mag4 vol4 ,,iii4 p4 #aic1 #ahhf4 ---- 7#hg7 ,on the leaf-beds and gravels of ,ardtun1 ,carsaig1 c41 in ,mull4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xliii4 p4 #bgj1 #ahhg4 ,geikie1 ,a4 7#ic7 ,a ,text-book of ,geology4 ,london1 #ahic4 7,edit iii47 ,geinitz1 ,h4 ,b4 7#ee7 ,die ,versteinerungen der ,steinkohlenformation in ,sachsen4 ,leipzig1 #ahee4 ,germar1 ,e4 ,f4 7#dd7 ,die ,versteinerungen des ,steinkohlengebirges von ,wettin und ,lbejn in ,saalkreis1 bildlich dargestellt und beschrieben4 ,halle1 #ahdd-ec4 ,germar1 ,e4 ,f4 and ,kaulfuss1 ,f4 7#ca7 ber einige merkwrdige ,pflanzen-,abdrcke4 ,nova ,acta ,leop4 ,car4 vol4 ,,xv4 #ahca4 ,giesenhagen1 ,k4 7#ib7 ber hygrophile ,farne4 ,flora1 vol4 ,,lxxvi4 p4 #aeg1 #ahib4 ,gomont1 ,m4 7#hh7 ,recherches sur les enveloppes cellulaires des nostocaces filamenteuses4 ,bull4 ,soc4 ,bot4 ,france1 vol4 ,,xxxv4 p4 #bjd1 #ahhh4 ---- 7#ib7 ,monographie des ,oscillaries4 ,ann4 ,sci4 ,nat4 vol4 ,,xv4 #g p4 #bfc1 #ahib4 ,gppert1 ,h4 ,r4 7#cf7 ber den ,zustand in welchem sich die fossilen ,pflanzen befinden1 und ber den ,versteinerungsprocess insbesondere4 ,poggendorf's ,annalen1 vol4 ,,xxxviii4 p4 #efa1 #ahcf4 7,also the ,edinburgh ,new ,philosophical ,journal1 vol4 ,,xxiii4 p4 #gc1 #ahcg47 ---- 7#cf7 ,die fossilen ,farnkruter4 ,nova ,acta ,leop4 ,car4 vol4 ,,xvii4 7,supplt47 #ahcf4 ---- 7#de7 ,tchihatcheff's ,voyage ,scientifique dans l',alta oriental1 pp4 #cgi-cij4 ,paris1 #ahde4 ---- 7#eb7 ber die ,flora des bergangsgebirges4 ,nova ,acta ,ac4 ,caes4 ,leop4 ,car4 vol4 ,,xxii4 7,supplt47 #aheb4 ---- 7#eg7 ber den versteinten ,wald von ,radowenz bei ,adersbach in ,bhmen und ber den ,versteinerungsprocess berhaupt4 ,jahrb4 k4 k4 ,geol4 ,reichs4 ,wien1 vol4 ,,viii4 p4 #gbe1 #aheg4 ---- 7#fj7 ber die fossile ,flora der ,silurischen1 der ,devonischen und unteren ,kohlenformation4 ,nova ,acta ,ac4 ,caes4 ,leop4 ,car4 vol4 ,,xxvii4 p4 #dbg1 #ahfj4 ---- 7#fd7 ,die fossile ,flora der ,permischen ,formation4 ,palaeontograph4 vol4 ,,xii4 #ahfd-fe4 ,gppert1 ,h4 ,r4 and ,berendt1 ,g4 ,c4 7#de7 ,der ,bernstein und die in ihm befindlichen ,pflanzenreste der ,vorwelt4 ,berlin1 #ahde4 ,gppert1 ,h4 ,r4 and ,menge1 ,a4 7#hc7 ,die ,flora des ,bernsteins4 ,vol4 ,i4 ,danzig1 #ahhc4 ,gottsche1 ,c4 ,m4 7#hf7 ber die im ,bernstein eingeschlossenen ,lebermoose4 ,bot4 ,central4 vol4 ,,xxv4 p4 #ie1 #ahhf4 ,grand',eury1 ,c4 7#fi7 ,observations sur les ,calamites et les ,asterophyllites4 ,compt4 ,rend4 vol4 ,,lxviii4 p4 #gje1 #ahfi4 ---- 7#gg7 ,flora ,carbonifre du dpt4 de la ,loire et du centre de la ,france4 ,mm4 ,ac4 ,sci4 ,paris1 vol4 ,,xxiv4 #ahgg4 ---- 7#hb7 ,mmoire sur la formation de la houille4 ,ann4 ,mines1 vol4 ,i4 #ahhb4 ---- 7#hg7 ,formation des couches de houille et du terrain houiller4 ,mm4 ,soc4 ,gol4 ,france1 vol4 ,,iv4 #c #ahhg4 ---- 7#hi7 ,calamaries4 ,arthropitus et ,calamodendron4 ,compt4 ,rend4 vol4 ,,cviii4 p4 #ajhf1 #ahhi4 ---- 7#ij7 ,gologie et palontologie du bassin houiller du ,gard4 ,st4 tienne1 #ahij4 ,greville1 ,r4 ,k4 7#dg7 ,notice of a new species of ,dawsonia4 ,ann4 ,mag4 ,nat4 ,hist4 vol4 ,,xix4 p4 #bbf1 #ahdg4 ,guillemard1 ,f4 ,h4 ,h4 7#hf7 ,the ,cruise of the 8,marchesa0 to ,kamschatka and ,new ,guinea4 ,london1 #ahhf4 ,gmbel1 ,c4 ,w4 7#ga7 ,die sogenannten ,nulliporen4 ,pt4 ii4 ,abh4 k4 ,mnchener ,akad4 ,wiss4 vol4 ,,xi4 p4 #bca1 #ahga4 ,gutbier1 ,a4 von4 7#di7 ,die ,versteinerungen des ,rothliegendes in ,sachsen4 ,dresden and ,leipzig1 #ahdi4 ,haberlandt1 ,g4 7#if7 ,physiologische ,pflanzenanatomie 7edit4 #b74 ,leipzig1 #ahif4 ,hall1 ,j4 7#dg7 and 7#eb7 ,natural ,history of ,new ,york4 ,palaeontology4 ,vol4 ,i4 ,albany1 #ahdg1 vol4 ,,ii4 ,albany1 #aheb4 ,harker1 ,a4 7#ie7 ,petrology for students4 ,cambridge1 #ahie4 ,harper1 ,r4 ,a4 7#ie7 ,die ,entwickelung des ,peritheciums bei ,sphaerotheca ,castagnei4 ,bericht4 deutsch4 ,bot4 ,ges4 vol4 ,,xiii4 p4 #dge1 #ahie4 ,harrison1 ,j4 ,b4 7#ia7 ,vide ,jukes-,browne4 ,hartig1 ,r4 7#gh7 ,die ,zersetzungserscheinungen des ,holzes der ,nadelholzbume und der ,eiche in frstlicher botanischer und chemischer ,richtung bearbeitet4 ,berlin1 #ahgh4 ---- 7#id7 ,text-book of the diseases of trees4 7,translation by ,w4 ,somerville47 ,london1 #ahid4 ,harvey1 ,w4 ,h4 7#eh7 ,phycologia ,australica4 ,london1 #aheh4 ,hauck1 ,f4 7#he7 ,die ,meeresalgen ,deutschlands und ,oesterreichs4 ,rabenhorst's ,kryptogamen ,flora1 vol4 ,,ii4 ,leipzig1 #ahhe4 ,heer1 ,o4 7#ec7 ,beschreibung der angefhrten ,pflanzen und ,insekten4 ,neue ,denksch4 ,schweiz4 ,ges4 gesammt4 ,wiss4 ,vol4 ,,xiii4 #e1 p4 #aag1 #ahec4 7,appendix to a ,memoir by ,a4 ,escher v4 d4 ,linth47 ---- 7#ee7 ,flora ,tertiaria ,helvetiae4 ,winterthur1 #ahee4 ---- 7#fe7 ,die ,urwelt der ,schweiz4 ,zrich1 #ahfe4 ---- 7#fh7 ,flora fossilis ,arctica4 ,die fossile ,flora der ,polarlnde4 ,vol4 ,i4 #ahfh4 ,vol4 ,,ii4 #ahga4 ,vol4 ,,iii4 #ahge4 ,vol4 ,,iv4 #ahgg4 ,vol4 ,v4 #ahgh4 ,vols4 ,,vi4 and ,,vii41 ,flor4 foss4 ,grn4 ,die fossile ,flora ,grnlands4 #ahhb-hc4 ---- 7#gf7 ,flora fossilis ,helvetiae4 ,zrich1 #ahgf4 ---- 7#gg7 ,beitrge zur ,jura-,flora ,ost-,sibiriens und des ,amurlandes4 ,flora fossilis ,arctica1 vol4 ,v4 ,zrich1 #ahgg4 ---- 7#hb7 ,nachtrge zur ,jura-,flora ,sibiriens4 7,flor4 foss4 ,grnlandica1 ,th4 i47 ,flora foss4 ,arct4 vol4 ,,vi4 ,zrich1 #ahhb4 ,heim1 ,a4 7#gh7 ,untersuchungen ber den ,mechanismus der ,gebirgsbildung4 ,basel1 #ahgh4 ,heinricher1 ,e4 7#hb7 ,die nheren ,vorgnge bei der ,sporenbildung der ,salvina natans verglichen mit den der brigen ,rhizocarpeen4 ,sitzber4 kais4 ,akad4 ,wiss4 ,wien1 vol4 ,,lxxxvii4 ,abt4 ,i4 p4 #did1 #ahhb4 ,hensen1 ,v4 7#ib7 ,ergebnisse der in dem ,atlantischen ,ocean ,plankton-,expedition der ,humboldt ,stiftung4 ,kiel and ,leipzig1 vol4 ,i4 #ahib4 ,herzer1 ,h4 7#ic7 ,a new fungus from the ,coal-,measures4 ,american ,geologist1 vol4 ,,xi4 p4 #cfe1 #ahic4 ,hick1 ,t4 7#gh7 and 7#ha7 ,vide ,cash1 ,w4 ---- 7#ic7 ,calamostachys ,binneyana1 ,schimp4 ,proc4 ,yorks4 ,geol4 ,polytech4 ,soc4 vol4 ,,xii4 pt4 ,,iv4 p4 #bgi1 #ahic4 ---- 7#ic7 ,the fruit-spike of ,calamites4 ,nat4 ,science1 vol4 ,,ii4 p4 #ced1 #ahic4 ---- 7#id7 ,on the primary structure of the stem of ,calamites4 ,proc4 ,lit4 and ,phil4 ,soc4 #d vol4 ,,viii4 p4 #aeh4 ,manchester1 #ahid4 ---- 7#ie7 ,on the structure of the leaves of ,calamites4 ,ibid4 vol4 ,,ix4 #d p4 #agi1 #ahie4 ---- 7#if7 ,on a sporangiferous spike1 from the ,middle ,coal-,measures1 near ,rochdale4 ,ibid4 vol4 ,x4 #d p4 #gc1 #ahif4 ,hicks1 ,h4 7#ha7 ,on the discovery of some remains of plants at the base of the ,denbighshire grits1 near ,corwen1 ,n4 ,wales2 with an appendix by ,r4 ,etheridge4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xxxvii4 p4 #dhb1 #ahha4 ,hinde1 ,g4 ,j4 and ,fox1 ,h4 7#ie7 ,on a well-marked horizon of ,radiolarian rocks in the ,lower ,culm-,measures of ,devon1 ,cornwall and ,west ,somerset4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,li4 p4 #fji1 #ahie4 ,hirschwald1 ,j4 7#gc7 ber ,umwandlung von verstrzter ,holzzimmerung in ,braunkohle im alten ,mann der ,grube ,dorothea bei ,clausthal4 ,zeit4 deutsch4 geol ,ges4 vol4 ,,xxv4 p4 #cfd1 #ahgc4 ,holmes1 ,e4 ,m4 and ,batters1 ,e4 ,a4 7#ij7 ,a revised list of ,british marine algae4 ,annals ,bot4 vol4 ,v4 p4 #fc1 #ahij-ia4 ,holmes1 ,w4 ,h4 7#hj7 ,fossil forests of the ,volcanic ,tertiary formations of the ,yellowstone ,national ,park4 ,bull4 ,u4 ,s4 ,geol4 ,surv4 vol4 ,v4 no4 #b1 #ahhj4 ,hooker1 ,j4 ,d4 7#dd7 ,the ,botany of the ,antarctic voyage of ,h4 ,m4 ,discovery ,ships 8,erebus0 and 8,terror0 in the years #ahci-dc4 ,london1 #ahdd4 ---- 7#ec7 ,vide ,strickland4 ---- 7#ha7 ,presidential ,address before ,section ,e of the ,york meeting of the ,british ,association4 ,annual ,report1 p4 #gbg1 #ahha4 ---- 7#hi7 ,on ,pachytheca4 ,annals ,bot4 vol4 ,,iii4 p4 #ace1 #ahhi4 ---- 7#ia7 ,himalayan ,journals4 ,london1 #ahia4 7,minerva ,library ,edition47 ,hooker1 ,w4 ,j4 7#bj7 ,musci ,exotici4 ,vol4 ,,ii4 ,london1 #ahbj4 ---- 7#fa7 ,a second century of ferns4 ,london1 #ahfa4 ,howse1 ,r4 7#hh7 ,a catalogue of fossil plants from the ,hutton ,collection4 ,newcastle1 #ahhh4 ,hughes1 ,t4 ,mc,kenny 7#gi7 ,on the relation of the appearance and duration of the various forms of life upon the earth to the breaks in the continuity of the sedimentary strata4 ,proc4 ,phil4 ,soc4 ,cambridge1 vol4 ,,iii4 pt4 ,,vi4 p4 #bdg1 #ahgi4 ---- 7#hd7 ,on some tracks of terrestrial and freshwater animals4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xl4 p4 #agh1 #ahhd4 ,humboldt1 ,a4 von4 7#dh7 ,cosmos4 7,translated by ,e4 ,c4 ,ott47 ,london1 #ahdh4 ,huxley1 ,t4 ,h4 7#ic7 ,science and ,hebrew tradition4 ,collected ,essays1 vol4 ,,iv4 ,london1 #ahic4 ,jger1 ,g4 ,f4 7#bg7 ber die ,pflanzenversteinerungen welche in dem ,bausandstein von ,stuttgart vorkommen4 ,stuttgart1 #ahbg4 ,james1 ,j4 ,f4 7#ic7 ,studies in the problematic organisms4 ,no4 #b4 ,the genus ,fucoides4 ,journ4 ,cincinnati ,soc4 ,nat4 ,hist4 #ahic4 ---- 7#ic7 ,notes on fossil fungi4 ,u4 ,s4 ,dpt4 ,agriculture1 vol4 ,,vii4 no4 #c1 p4 #bfh1 #ahic4 ---- 7#ic7 ,fossil fungi4 ,translated from the ,french of ,r4 ,ferry1 with remarks4 ,journ4 ,cincinnati ,soc4 ,nat4 ,hist4 #ahic1 p4 #id4 ,judeich1 ,j4 ,f4 and ,nitsche1 ,f4 7#ie7 ,lehrbuch der mitteleuropischen ,forstinsektenkunde4 ,vienna1 #ahie4 ,jukes-,browne1 ,a4 ,j4 7#hf7 ,the ,student's ,handbook of ,historical ,geology4 ,london1 #ahhf4 ,jukes-,browne1 ,a4 ,j4 and ,harrison1 ,j4 ,b4 7#ia7 ,the ,geology of ,barbados4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xlvii4 p4 #aig1 #ahia4 ,kayser1 ,e4 7#ie7 ,text-book of ,comparative ,geology4 7,translated and edited by ,p4 ,lake47 ,london1 #ahie4 ,kent1 ,s4 7#ic7 ,the ,great ,barrier ,reef of ,australia4 ,london1 #ahic4 ,kickx1 ,j4 ,j4 7#fd7 ,vide ,coemans1 ,e4 ,kidston1 ,r4 7#hc7 ,report on fossil plants collected by the ,geological ,survey of ,scotland in ,eskdale and ,liddesdale4 ,trans4 ,r4 ,soc4 ,edinburgh1 vol4 ,,xxx4 p4 #eca1 #ahhc4 ---- 7#hc7 ,on the affinities of the genus ,pothocites1 ,paterson2 with the description of a specimen from ,glencartholm1 ,eskdale4 ,trans4 ,bot4 ,soc4 ,edinburgh1 vol4 ,,xvi4 p4 #bh4 ---- 7#hf7 ,catalogue of the ,palaeozoic plants in the department of geology and palaeontology1 ,british ,museum4 ,london1 #ahhf4 ---- 7#hh7 ,vide ,young4 ---- 7#ij7 ,on the fructification of ,sphenophyllum trichomatosum1 ,stur1 from the ,yorkshire ,coal-field4 ,proc4 ,r4 ,soc4 ,phys4 ,edinburgh1 vol4 ,,xi4 p4 #ef1 #ahij-ia4 ---- 7#ij7 ,note on the ,palaeozoic species mentioned in ,lindley and ,hutton's fossil ,flora4 ,proc4 ,r4 ,soc4 ,phys4 ,edinburgh1 vol4 ,x4 p4 #cde1 #ahij-ia4 ---- 7#ib7 ,on the occurrence of the genus ,equisetum 7,e4 ,hemingwayi1 ,kidston7 in the ,yorkshire ,coal-,measures4 ,annals ,mag4 ,nat4 ,hist4 vol4 ,,ix4 #f p4 #ach1 #ahib4 ---- 7#ic7 ,on the fossil plants of the ,kilmarnock1 ,galston1 and ,kilwinning ,coal-fields1 ,ayrshire4 ,trans4 ,r4 ,soc4 ,edinburgh1 vol4 ,,xxxvii4 pt4 ,,ii4 p4 #cjg1 #ahic4 ---- 7#id7 ,on the various divisions of ,british ,carboniferous rocks as determined by their fossil flora4 ,proc4 ,r4 ,soc4 ,phys4 ,soc4 ,edinburgh1 vol4 ,,xii4 p4 #ahc1 #ahid4 ,kinahan1 ,j4 ,r4 7#eh7 ,the genus ,oldhamia4 ,trans4 ,r4 ,irish ,acad4 vol4 ,,xxiii4 p4 #edg1 #aheh4 ,kippis1 ,a4 7#gh7 ,a narrative of the voyage round the world1 performed by ,captain ,james ,cook4 ,london1 #ahgh4 ,kitton1 ,f4 7#ha7 ,vide ,shrubsole1 ,w4 ,h4 ,k,jellman1 ,f4 ,r4 7#hc7 ,the ,algae of the ,arctic ,sea4 ,kongl4 ,svensk ,vetenskaps ,akad4 ,hand4 vol4 ,,xx4 no4 #e1 #ahhc4 ,knowlton1 ,f4 ,h4 7#hi7 ,fossil wood and lignite of the ,potomac formation4 ,bull4 ,u4 ,s4 ,geol4 ,surv4 no4 #ef1 #ahhi4 ---- 7#hi7 ,description of a problematic organism from the ,devonian at the falls of the ,ohio4 ,amer4 ,journ4 ,science1 vol4 ,,xxxvii4 #c p4 #bjb1 #ahhi4 ---- 7#id7 ,fossil plants as aids to geology4 ,journ4 ,geol4 vol4 ,,ii4 no4 #d1 p4 #cfe1 #ahid4 ---- 7#if7 ,the nomenclature question4 ,bot4 ,gazette1 vol4 ,,xxi4 p4 #hb1 #ahif4 ,koechlin-,schlumberger1 ,j4 ,vide ,schimper1 ,w4 ,p4 ,klliker1 ,a4 7#ei7 ,on the frequent occurrence of vegetable parasites in the hard structures of animals4 ,annals ,mag4 ,nat4 ,hist4 vol4 ,,iv4 #c p4 #cjj1 #ahei4 ---- 7#ei7 ber das ausgebreitete ,vorkommen von pflanzlichen ,parasiten in den ,hartgebilden niederer ,thiere4 ,zeitsch4 wiss4 ,zool4 vol4 ,x4 p4 #bae1 #ahei4 ,knig1 ,c4 7#bi7 ,vide ,murchison 7#bi7 p4 #bih4 ,kuntze1 ,o4 7#hj7 ber ,geysirs und nebenan entstehende verkieselte ,bume4 ,ausland1 #ahhj1 p4 #cfa4 ,lake1 ,p4 7#ie7 ,the ,denbighshire series of ,south ,denbighshire4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,li4 p4 #i1 #ahie4 ,lamarck1 de4 7#af7 ,histoire naturelle des animaux sans vertbres4 ,paris1 vol4 ,,ii4 #ahaf4 ,lamouroux1 ,j4 7#ba7 ,exposition mthodique des genres de l'ordre des ,polypiers4 ,paris1 #ahba4 ,lapworth1 ,c4 7#ha7 ,appendix to ,w4 ,keeping's ,geology of ,central ,wales4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xxxvii4 p4 #aga1 #ahha4 ,leckenby1 ,j4 7#fd7 ,on the sandstones and shales of the ,oolites of ,scarborough1 with descriptions of some new species of fossil plants4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xx4 p4 #gd1 #ahfd4 ,lehmann4 7#agef7 ,dissertation sur les fleurs de l',aster montanus4 ,hist4 ,acad4 ,r4 ,sci4 et bell4 lett4 ,berlin1 #agef4 ,lesquereux1 ,l4 7#ff7 ,geological ,survey of ,illinois4 ,vol4 ,,ii4 ,new ,york1 #ahff4 ---- 7#gj7 ,ibid4 vol4 ,,iv4 #ahgj4 ---- 7#gi7 ,atlas to the ,coal ,flora of ,pennsylvania and of the ,carboniferous formation throughout the ,united ,states4 ,second ,geol4 ,surv4 ,penn4 ,report of ,progress ,p4 ,harrisburg1 #ahgi4 ---- 7#hj7 ,description of the ,coal ,flora of the ,carboniferous formation in ,pennsylvania and throughout the ,united ,states4 ,ibid4 #ahhj and #ahhd4 ---- 7#hd7 ,ibid4 vol4 ,,iii4 #ahhd4 ---- 7#hg7 ,a species of ,fungus recently discovered in the shale of the ,darlington ,coal bed at ,canneton1 ,pennsylvania4 ,proc4 ,amer4 ,phil4 ,soc4 vol4 ,,xvii4 p4 #agc1 #ahhg4 ,lhwyd 7,luidius71 ,e4 7#agfj7 7#afii7 ,lithophylacii ,britannici ichnographia4 ,oxford1 #agfj4 7,first edition published in #afii47 ,limpricht1 ,k4 ,g4 7#ij7 ,die ,laubmoose4 ,rabenhorst's ,kryptogamen ,flora1 vol4 ,,iv4 ,leipzig1 #ahij4 ,lindenberg1 ,j4 ,b4 ,w4 7#ci7 ,species ,hepaticarum4 ,bonn1 #ahci4 ,lindley1 ,j4 and ,hutton1 ,w4 7#ca7 ,the fossil ,flora of ,great ,britain4 ,london1 #ahca-cg4 ,vol4 ,i4 ,pls4 #a-gi2 #ahca-cc4 ,vol4 ,,ii4 ,pls4 #hj-aef2 #ahcc-ce4 ,vol4 ,,iii4 ,pls4 #aeg-bcj2 #ahcg4 ,linnarsson1 ,j4 ,g4 ,o4 7#fi7 ,on some fossils found in the ,eophyton ,sandstones at ,lugns in ,sweden4 ,geol4 ,mag4 vol4 ,,vi4 p4 #cic1 #ahfi4 ,lister1 ,a4 7#id7 ,a monograph of the ,mycetozoa1 being a descriptive ,catalogue of the species in the ,herbarium of the ,british ,museum4 ,london1 #ahid4 ,ludwig1 ,r4 7#eg7 ,fossile ,pflanzen aus der jngsten ,wetterauer ,braunkohle4 ,palaeontograph1 vol4 ,v4 p4 #ha1 #aheg4 ---- 7#ei7 ,fossile ,pflanzen aus der ltesten ,abtheilung der ,rheinisch-,wetterauer ,tertir-,formation4 ,palaeontograph1 vol4 ,,viii4 ,luerssen1 ,c4 7#hi7 ,die ,farnpflanzen oder ,gefssbndelkryptogamen4 ,rabenhorst's ,krypt4 ,flora1 vol4 ,,iii4 ,leipzig1 #ahhi4 ,lydekker1 ,r4 7#hi7 ,vide ,nicholson4 ,lyell1 ,c4 7#bi7 ,on a recent formation of freshwater limestone in ,forfarshire4 ,trans4 ,geol4 ,soc4 vol4 ,,ii4 #b p4 #gc1 #ahbi4 ---- 7#de7 ,travels in ,north ,america4 ,london1 #ahde4 ---- 7#ee7 ,a manual of ,elementary ,geology4 ,london1 #ahee1 7,edit4 #e74 ---- 7#fg7 ,principles of ,geology4 ,london1 #ahfg1 7,edit4 #aj74 ---- 7#gh7 ,elements of ,geology4 ,london1 #ahgh1 7,edit4 #c74 ,m#8,coy1 ,f4 7#dg7 ,on the ,fossil ,botany and ,zoology of the rocks associated with the coal of ,australia4 ,annals ,mag4 ,nat4 ,hist4 vol4 ,,xx4 p4 #ade1 #ahdg4 ,mahr1 -- 7#fh7 ber ,sphenophyllum ,thoni1 eine neue ,art aus dem ,steinkohlengebirge von ,ilmenau4 ,zeit4 deutsch4 geol4 ,ges4 vol4 ,,xx4 p4 #dcc1 #ahfh4 ,mantell1 ,g4 7#dd7 ,medals of ,creation4 ,,london1 #ahdd4 ,marsh1 ,o4 ,c4 7#ga7 ,notice of a fossil forest in the ,tertiary of ,california4 ,amer4 ,journ4 ,sci4 vol4 ,i4 #c p4 #bff1 #ahga4 ,martin1 ,w4 7#ji7 ,petrificata ,derbiensia4 ,wigan1 #ahji4 ,maskell1 ,w4 ,m4 7#hg7 ,the ,scale-insects4 ,wellington1 #ahhg4 ,massalongo1 ,e4 ,g4 7#ea7 ,sopra le piante fossili dei terreni terziarj del ,vicentino1 ,osservazioni1 c4 ,padova1 #ahea4 ---- 7#ei7 ,studii sulla flora fossile e geologia stratigrafica del ,senigalliese4 ,imola1 #ahei4 ,matthew1 ,g4 ,f4 7#hi7 ,the ,cambrian organisms in ,acadia4 ,trans4 ,r4 ,soc4 ,canada 7,sect4 ,,iv47 #ahhi1 p4 #ace4 ,meek1 ,f4 ,b4 7#gc7 ,report of the ,geological ,survey of ,ohio4 ,vol4 ,i4 ,meschinelli1 ,a4 7#ib7 ,fungi fossiles4 ,in ,p4 ,a4 ,saccardo's ,sylloge ,fungorum4 ,vol4 ,x4 p4 #gda1 ,patavii1 #ahib4 ,michelin1 ,h4 7#dj7 ,iconographie zoophytologique4 ,paris1 #ahdj-dg4 ,migula1 ,w4 7#ij7 ,die ,characeen4 ,rabenhorst's ,kryptogamen ,flora1 vol4 ,v4 ,leipzig1 #ahij4 ,milde1 ,j4 7#fg7 ,monographia ,equisetorum4 ,nova ,act4 ,acad4 ,caes4 ,leop4 ,car4 vol4 ,,xxxii4 p4 #a1 #ahfg4 ,morris1 ,j4 7#ed7 ,a catalogue of ,british fossils4 ,london1 #ahed1 7,edit4 #b74 ,morton1 ,g4 ,h4 7#ia7 ,the geology of the country around ,liverpool4 ,london1 #ahia1 7,edit4 #b74 ,moseley1 ,h4 ,n4 7#ge7 ,notes on freshwater algae obtained at the boiling springs at ,furnas1 ,st4 ,michael's1 ,azores1 and the neighbourhood4 ,with notes by ,w4 ,t4 ,thiselton-,dyer4 ,journ4 ,linn4 ,soc4 vol4 ,,xiv4 7,botany7 p4 #cba1 #ahge4 ,mougeot1 ,a4 7#dd7 ,vide ,schimper4 ---- 7#eb7 ,essai d'une flore du nouveau ,grs ,rouge des ,vosges4 ,epinal1 #aheb4 ,munier-,chalmas1 ,e4 7#gg7 ,observations sur les algues calcaires appartenant au groupe des ,siphones verticilles 7,dasyclades ,harv47 et confondues avec les ,foraminifres4 ,compt4 ,rend4 vol4 ,,lxxxv4 p4 #had1 #ahgg4 ---- 7#gi7 ,observations sur les algues calcaires confondues avec les ,foraminifres et appartenant au groupe des ,siphones dichotomes4 ,bull4 ,soc4 ,gol4 #c vol4 ,,vii4 p4 #ffa1 #ahgi4 ,murchison1 ,r4 ,i4 7#bi7 ,on the ,coal-field of ,brora in ,sutherlandshire1 and some other stratified deposits in the ,north of ,scotland4 ,trans4 ,geol4 ,soc4 #b vol4 ,,ii4 p4 #bic4 ---- 7#gb7 ,siluria4 7,edit4 #e47 ,london1 #ahgb4 ,murray1 ,g4 7#ib7 ,on a fossil alga belonging to the genus ,caulerpa1 from the ,oolite4 ,phycological ,memoirs1 pt4 ,i4 p4 #aa1 #ahib4 ---- 7#ie7 ,an introduction to the study of seaweeds4 ,london1 #ahie4 ---- 7#ie7 ,calcareous pebbles formed by ,algae4 ,phycol4 ,mem4 pt4 ,,iii4 p4 #gd1 #ahie4 ---- 7#ie7 ,a new part of ,pachytheca4 ,ibid4 p4 #ga1 #ahie4 ---- 7#ig7 ,on the reproduction of some marine ,diatoms4 ,proc4 ,r4 ,soc4 ,edinburgh1 vol4 ,,xxi4 p4 #bjg1 #ahig4 ,murray1 ,g4 and ,blackman1 ,v4 ,h4 7#ig7 ,coccospheres and ,rhabdospheres4 ,nature1 vol4 ,,lv4 p4 #eaj1 #ahig4 ,murray1 ,j4 and ,renard1 ,a4 7#ia7 ,vide 8,challenger40 ,nathorst1 ,a4 ,g4 7#hj7 ,reseberttelse4 fversigt ,kongl4 ,vetenskaps-,akad4 ,frh4 #ahhj1 no4 #e1 p4 #bc4 ---- 7#ha7 ,om spr af ngra evertebrerade djur m4 m4 och deras paleontologiska betydelse4 ,k4 ,svensk4 ,vet4-,akad4 ,hand4 vol4 ,,xviii4 no4 #g1 #ahha4 ---- 7#ha7 ,om ,aftryck af ,medusar i ,sveriges ,kambriska layer4 ,k4 ,svensk4 ,vet4-,akad4 ,hand4 vol4 ,,xix4 no4 #a1 #ahha4 ---- 7#hc7 ,quelques remarques concernant la question des algues fossiles4 ,bull4 ,soc4 ,gol4 #c vol4 ,,xi4 p4 #deb1 #ahhc4 ---- 7#hc7 ,fossil ,algae4 7,letter47 ,nature1 vol4 ,,xxviii4 p4 #eb1 #ahhc4 ---- 7#hf7 ,nouvelles observations sur des traces d'animaux et autres phnomnes d'origine purement mcanique dcrits comme 8algues fossiles40 ,kongl4 ,svensk4 ,vetenskaps-,akad4 ,hand4 vol4 ,,xxi4 no4 #ad4 ,stockholm1 #ahhf4 ---- 7#ij7 ,beitrge zur mesozoischen ,flora ,japans4 ,denkschr4 k4 ,akad4 ,wiss4 ,wien1 vol4 ,,lviii4 #ahij4 ---- 7#id7 ,zur palozoischen ,flora der arktischen ,zone4 ,kongl4 ,svensk4 ,vetenskaps-,akad4 ,hand4 vol4 ,,xxvi4 no4 #d1 #ahid4 ---- 7#id7 ,sveriges ,geologi4 ,stockholm1 #ahid4 ,naunyn1 ,b4 7#if7 ,a treatise on ,cholelithiasis4 7,translation by ,a4 ,e4 ,garrod47 ,new ,sydenham ,society1 ,london1 #ahif4 ,neumayr1 ,m4 7#hc7 ber klimatische ,zonen whrend der ,jura- und ,kreidezeit4 ,denkschr4 k4 ,ak4 ,wiss4 ,wien1 vol4 ,,xlvii4 #ahhc4 ,newberry1 ,j4 ,s4 7#hh7 ,fossil fishes and fossil plants of the ,triassic rocks of ,new ,jersey and the ,connecticut ,valley4 ,u4 ,s4 ,geol4 ,surv4 7,monographs71 vol4 ,,xiv4 #ahhh4 ---- 7#ia7 ,the genus ,sphenophyllum4 ,journ4 ,cincinnati ,soc4 ,nat4 ,hist4 #ahia1 p4 #bab4 ,nicholson1 ,h4 ,a4 7#fi7 ,on the occurrence of plants in the ,skiddaw ,slates4 ,geol4 ,mag4 vol4 ,,vi4 p4 #did1 #ahfi4 ,nicholson1 ,h4 ,a4 and ,etheridge1 ,r4 junr4 7#hj7 ,a monograph of the ,silurian fossils of the ,girvan district in ,ayrshire4 ,edinburgh1 #ahhj4 ,nicholson1 ,h4 ,a4 and ,lydekker1 ,r4 7#hi7 ,a manual of ,palaeontology4 ,london1 #ahhi4 ,nicol1 ,w4 7#cd7 ,observations on the structure of recent and fossil ,coniferae4 ,edinb4 ,new ,phil4 ,journ4 vol4 ,,xvi4 p4 #acg1 #ahcd4 ,noll1 ,f4 7#ie7 ,lehrbuch der ,botanik fr ,hochschulen4 ,strasburger1 ,noll1 ,schimper und ,schenk4 ,jena1 #ahie1 p4 #bdh 7,edit4 #b74 ,parkinson1 ,j4 7#aa7 ,organic ,remains of a former world4 ,london1 #ahaa4 7,vol4 ,i4 #ahaa1 vol4 ,,ii4 #ahjh1 vol4 ,,iii4 #ahaa47 ,parsons1 ,j4 7#ageg7 ,an account of some fossil fruits and other bodies found in the island of ,sheppey4 ,phil4 ,trans4 vol4 ,l4 pt4 ,i4 p4 #cif1 #ageg4 ,paterson 7#da7 ,description of ,pothocites ,grantoni1 a new fossil vegetable from the ,coal ,formation4 ,trans4 ,bot4 ,soc4 ,edinburgh1 vol4 ,i4 p4 #de1 #ahda4 ,penhallow1 ,d4 ,p4 7#hi7 ,on ,nematophyton and allied forms from the ,devonian 7,erian7 of ,gasp and ,bay des ,chaleurs4 ,trans4 ,r4 ,soc4 ,canada1 vol4 ,,vi4 sect4 #d 7#ahhh74 ---- 7#ic7 ,notes on ,nematophyton crassum4 ,proc4 ,u4 ,s4 ,nat4 ,museum1 vol4 ,,xvi4 p4 #aae1 #ahic4 ---- 7#if7 ,nematophyton ,ortoni1 n4 sp4 ,annals ,bot4 vol4 ,x4 p4 #da1 #ahif4 ,petzholdt1 ,a4 7#da7 ber ,calamiten und ,steinkohlenbildung4 ,dresden and ,leipzig1 #ahda4 ,pfitzer1 ,e4 ,h4 ,h4 7#fg7 ber die ,schutzscheide4 ,pringsh4 ,jahrb4 ,wiss4 ,bot4 vol4 ,,vi4 p4 #bib1 #ahfg-fh4 ---- 7#ga7 ,untersuchungen ber ,bau und ,entwickelung der ,bacillariaceen4 ,hanstein's ,bot4 ,abhand4 #ahga4 ,philippi1 ,r4 ,a4 7#cg7 ,beweis das die ,nulliporen ,pflanzen sind4 ,wiegmann1 ,archiv4 vol4 ,i4 ,jahrg4 #c1 p4 #chg1 #ahcg4 ,phillips1 ,j4 7#bi7 ,illustrations of the ,geology of ,yorkshire4 ,york1 #ahbi4 ---- 7#ge7 ,ibid4 7,edit4 #c7 edited by ,r4 ,etheridge4 ,london1 #ahge4 ,phillips1 ,w4 7#ic7 ,the breaking of the ,shropshire ,meres4 ,midland ,naturalist1 vol4 ,,xvi4 p4 #ef1 #ahic4 ,plot1 ,r4 7#agje7 ,the ,natural ,history of ,oxfordshire4 ,oxford1 #agje4 ,potoni1 ,r4 7#hg7 ,die fossile ,pflanzen-,gattung ,tylodendron4 ,jahrb4 k4 ,preuss4 geol4 ,landesanst4 #ahhg1 p4 #cac4 ---- 7#ij7 ,der im ,lichthof der ,knigl4 ,geol4 ,landesanstalt und ,bergakademie aufgestellte ,baumstumpf mit ,wurzeln aus dem ,carbon des ,piesberges4 ,ibid4 #ahij1 p4 #bdf4 ---- 7#ib7 ,der ussere ,bau der ,bltter von ,annularia stellata 7,schloth47 mit ausblicken auf ,equisetites zeaeformis 7,schloth47 ,andrae1 und auf die ,bltter von ,calamites varians ,sternb4 ,ber4 deutsch4 bot4 ,ges4 vol4 ,x4 ,heft #h1 p4 #efa1 #ahib4 ---- 7#ic7 ,die ,flora des ,rothliegenden von ,thringen4 7,th4 ,i47 ,jahrb4 k4 ,preuss4 geol4 ,landesanst4 vol4 ,,ix4 #ahic4 ---- 7#id7 ber die ,stellung der ,sphenophyllum im ,system4 ,ber4 deutsch4 bot4 ,ges4 ,bd4 ,,xii4 ,heft #d1 p4 #ig1 #ahid4 ---- 7#if7 ,die floristische ,gliederung des deutschen ,carbon und ,perm4 ,abhand4 k4 ,preuss4 geol4 ,landesanst4 7,n4 ,f47 ,heft4 ,,xxi4 p4 #a1 #ahif4 ---- 7#if7 ,palaeophytologische ,notizen4 ,naturwiss4 ,wochenschrift1 vol4 ,,xi4 no4 #aj1 p4 #aae1 #ahif4 ,quekett1 ,j4 7#ed7 ,lectures on ,histology4 ,vols4 ,i4 and ,,ii4 ,london1 #aheb-ed4 ,raciborski1 ,m4 7#id7 ,flora ,kopalna ogniotrwalych ,glinek ,krakowskich4 ,pamit4 ,akad4 ,umiejtnoci1 #ahid4 ,reinsch1 ,p4 ,f4 7#ha7 ,neue ,untersuchungen ber die ,mikrostruktur der ,steinkohle4 ,leipzig1 #ahha4 ,renault1 ,b4 7#gc7 ,recherches sur l'organisation des ,sphenophyllum et des ,annularia4 ,ann4 ,sci4 ,nat4 #e vol4 ,,xviii4 p4 #e1 #ahgc4 ---- 7#gf7 ,recherches sur la fructification de quelques vgtaux4 ,ann4 ,sci4 ,nat4 #f vol4 ,,iii4 p4 #e1 #ahgf4 ---- 7#gf7 ,nouvelles recherches sur la structure des ,sphenophyllum4 ,ann4 ,sci4 ,nat4 #f vol4 ,,iv4 p4 #bgg1 #ahgf4 ---- 7#hb7 ,cours de botanique fossile4 ,vol4 ,,ii4 ,paris1 #ahhb4 ---- 7#he7 ,recherches sur les vgtaux fossiles du genre ,astromyelon ,ann4 ,sci4 ,gol4 vol4 ,,xvii4 #ahhe4 ---- 7#ic7 ,bassin ,houiller et ,permien d',autun et d',epinac4 7,atlas47 tudes des gtes minraux de la ,france1 ,fasc4 ,,iv4 ,paris1 #ahic4 ---- 7#ie7 ,note sur les cuticles de ,tovarkovo4 ,soc4 ,hist4 ,nat4 d',autun1 #ahie4 ---- 7#ie7 ,sur quelques ,bactries des temps primaires4 ,autun1 #ahie4 ---- 7#if7 ,bassin ,houiller et ,permien d',autun et d',epinac4 7,text47 tudes des gtes minraux de la ,france1 ,fasc4 ,,iv4 ,paris1 #ahif4 ---- 7#if7 ,notice sur les travaux scientifiques4 ,autun1 #ahif4 ---- 7#if7 ,recherches sur les ,bactriaces fossiles4 ,ann4 ,sci4 ,nat4 #h vol4 ,,ii4 p4 #bge1 #ahif4 ,renault1 ,r4 and ,bertrand 7#id7 ,sur une bactrie coprophile de l'poque ,permienne4 ,compt4 ,rend4 vol4 ,,cxix4 p4 #cgg1 #ahid4 ,renault1 ,r4 and ,zeiller1 ,r4 7#hh7 tudes sur le terrain houiller de ,commentry4 ,st tienne1 #ahhh-ij4 ,pt4 ,i4 pp4 #a-cff1 #ahhh4 ,pt4 ,,ii4 pp4 #cfg-gdf1 #ahij4 8,report0 7#fb7 ,report of the ,jury trial in the action of declaration1 c4 at the instance of ,mr and ,mrs ,gillespie1 of ,torbanehill1 against ,messrs ,james ,russell and ,son1 ,coal-masters1 ,falkirk4 ,edinburgh1 #ahfb4 ,reuss1 ,a4 ,e4 7#fa7 ber die fossile ,gattung ,acicularia d',archiac4 ,sitzb4 d4 k4 ,akad4 ,wiss4 ,bd4 ,,xliii4 ,abth4 ,i4 p4 #g1 #ahfa4 ,rodway1 ,j4 7#ie7 ,in the ,guiana ,forest4 ,london1 #ahie4 ,rmer1 ,a4 7#ed7 ,beitrge zur geologischen ,kenntniss des nordwestlichen ,harzgebirges von ,friedrich4 ,palaeontograph4 vol4 ,,iii4 p4 #a1 #ahed4 ,rmer1 ,f4 7#fb7 ,beitrge zur geologischen ,kenntniss des nordwestlichen ,harzgebirges4 ,palaeontograph4 vol4 ,,ix4 #ahfb4 ---- 7#gj7 ,geologie von ,oberschlesien4 ,breslau1 #ahgj4 ,rosanoff1 ,s4 7#ff7 ,recherches anatomiques sur les ,mlobsies4 ,mm4 ,soc4 ,sci4 nat4 ,cherbourg1 vol4 ,,xi4 #ahfe4 ,rose1 ,c4 ,b4 7#ee7 ,on the discovery of parasitic borings in fossil fish-scales4 ,trans4 mic4 soc4 7,n4 ,s47 vol4 ,,iii4 p4 #g1 #ahee4 ,rosenvinge1 ,l4 ,k4 7#ic7 ,grnlands ,havalger4 ,conspectus florae ,groenlandicae4 ,pt4 ,,iii4 p4 #gfe4 ,grnlands ,havalger4 7,meddelelser om ,grnland4 ,,iii4 ,supplt4 #c71 #ahhg-id4 ,rothpletz1 ,a4 7#hj7 ,die ,flora und ,fauna der ,carbon ,culmformation bei ,hainischen in ,sachsen4 ,bot4 ,cent4 vol4 ,,ii4 7,gratis ,beilage #c71 #ahhj4 ---- 7#ij7 ber ,sphaerocodium ,bornemanni1 eine neue fossile ,kalkalge aus den ,raibler ,schichten der ,ostalpen4 ,bot4 ,cent4 vol4 ,,xli4 p4 #i1 #ahij4 ---- 7#ia7 ,fossile ,kalkalgen aus den ,familien der ,codiaceen und der ,corallineen4 ,zeit4 deutsch4 geol4 ,ges4 vol4 ,,xliii4 p4 #bie1 #ahia4 ---- 7#ib7 ber die ,bildung der ,oolithe4 ,bot4 ,cent4 vol4 ,,li4 p4 #bfe1 #ahib4 ---- 7#ib7 ber die ,diadematiden-,stacheln und ,haploporella fasciculata aus dem ,oligocn von ,astrupp4 ,bot4 ,cent4 vol4 ,,lii4 p4 #bce1 #ahib4 ---- 7#id7 ,ein geologischer ,querschnitt durch die ,ost-,alpen nebst ,anhang ber die sogenannte ,glarner ,doppelfalte4 ,stuttgart1 #ahid4 ---- 7#if7 ber die ,flysch-,fucoiden und einige andere fossile ,algen sowie ber liassische ,diatomeen fhrende ,hornschwmme4 ,zeit4 deutsch4 geol4 ,ges4 vol4 ,,xlviii4 p4 #hed1 #ahif4 ,royle1 ,j4 ,f4 7#ci7 ,illustrations of the ,botany and other branches of the ,natural ,history of the ,himalayan ,mountains and of the flora of ,cashmere4 ,london1 #ahci4 ,rultey1 ,f4 7#ib7 ,notes on ,crystallites4 ,min4 ,mag4 vol4 ,,ix4 p4 #bfa1 #ahia4 ,salter1 ,j4 ,w4 7#fc7 ,on some fossil crustacea from the ,coal-,measures and ,devonian rocks of ,british ,north ,america4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xix4 p4 #ge1 #ahfc4 ---- 7#gc7 ,a catalogue of ,cambrian and ,silurian fossils4 ,cambridge1 #ahgc4 ,saporta1 de ,g4 7#fh7 ,prodrome d'une flore fossile des travertins anciens de ,szanne4 ,mm4 ,soc4 ,gol4 ,france1 vol4 ,,viii4 #b #ahfe-fh4 ---- 7#gb7 ,plantes ,jurassiques4 ,palont4 ,fran4 ,vgtaux1 vols4 ,i-,,iv4 #ahgb-ahia4 ---- 7#gc7 ,ibid4 vol4 ,i4 ,algues1 quistaces1 ,characes1 ,fougres1 #ahgc4 ---- 7#ge7 ,ibid4 vol4 ,,ii4 ,cycades1 #ahge4 ---- 7#gg7 ,sur la dcouverte d'une plante terrestre dans la partie moyenne du terrain ,silurien4 ,compt4 ,rend4 vol4 ,,lxxxv4 p4 #ejj1 #ahgg4 ---- 7#gi7 ,le monde des plantes avant l'apparition de l'homme4 ,paris1 #ahgi4 ---- 7#ha7 ,vide ,saporta and ,marion4 ---- 7#hb7 ,a propos des algues fossiles4 ,paris1 #ahhb4 ---- 7#hd7 ,les organismes problmatiques des anciennes mers4 ,paris1 #ahhd4 ---- 7#hf7 ,nouveaux documents relatifs des fossiles vgtaux et des traces d'invertbrs associs dans les anciens terrains4 ,bull4 ,soc4 bot4 ,france1 vol4 ,,xiv4 #c p4 #djg1 #ahhf4 ---- 7#ia7 ,plantes ,jurassiques4 ,vol4 ,,iv4 ,paris1 #ahia4 ,saporta1 de ,g4 and ,marion1 ,a4 ,f4 7#ha7 ,l'volution du rgne vgtal4 ,les ,cryptogames4 ,paris1 #ahha4 ,schenk1 ,a4 7#fe7 ,vide ,schoenlein4 ---- 7#fg7 ,die fossile ,flora der ,grenzschichten des ,keupers und ,lias ,frankens4 ,wiesbaden1 #ahfg4 ---- 7#hc7 ,pflanzliche ,versteinerungen4 ,richthofen's 8,china10 vol4 ,,iv4 ,berlin1 #ahhc4 ---- 7#hh7 ,die fossile ,pflanzenreste4 7,handbuch der ,botanik47 ,breslau1 #ahhh4 ---- 7#ij7 ,vide ,schimper4 ,scheuchzer1 ,j4 ,t4 7#agbc7 ,herbarium diluvianum4 ,lugduni ,batavorum1 #agbc4 ,schiffner1 ,v4 and ,mller1 ,c4 7#ie7 ,engler und ,prantl2 ,die natrlichen ,pflanzenfamilien4 ,teil ,i4 ,abt4 #c4 ,leipzig1 #ahie4 ,schimper1 ,w4 ,p4 7#fe7 ,euptychium ,muscorum ,neocaledonicorum genus novum et genus ,spiridens4 ,nova ,acta ,acad4 ,caes4 ,leop4 ,car4 vol4 ,,xxxii4 #ahfe4 ---- 7#fi7 ,trait de ,palontologie vgtale4 ,paris1 vol4 ,i4 #ahfi1 vol4 ,,ii4 #ahgj-gb1 vol4 ,,iii4 #ahgd4 ---- 7#gd7 ,ibid4 ,atlas4 ,schimper1 ,w4 ,p4 and ,koechlin-,schlumberger1 ,j4 7#fb7 ,mmoire sur le ,terrain de transition des ,vosges4 ,mm4 ,soc4 ,sci4 ,nat4 ,strasbourg1 vol4 ,v4 #ahfb4 ,schimper1 ,w4 ,p4 and ,mougeot 7#dd7 ,monographie des plantes fossiles du grs bigarr de la ,chane des ,vosges4 ,leipzig1 #ahdd4 ,schimper1 ,w4 ,p4 and ,schenk1 ,a4 7#ij7 ,palaeophytologie4 ,zittel's ,handbuch der ,palaeontologie1 ,abt4 ,,ii4 ,munich and ,leipzig1 #ahij4 ,schlotheim1 ,e4 ,f4 von4 7#jd7 ,beschreibung merkwrdiger ,kruter-,abdrcke und ,pflanzen-,versteinerungen4 ,gotha1 #ahjd4 ---- 7#bj7 ,die ,petrefactenkunde auf ihrem jetzigen ,standpunkte durch die ,beschreibung seiner ,sammlung versteinerter und fossiler berreste des ,thier- und ,pflanzenreichs der ,vorwelt erlutert4 ,gotha1 #ahbj4 ---- 7#bb7 ,nachtrge zur ,petrefactenkunde4 ,gotha1 #ahbb-bc4 ,schlter1 ,c4 7#gi7 ,coelotrochium ,decheni1 eine ,foraminifere aus dem ,mitteldevon4 ,zeit4 deutsch4 geol4 ,ges4 vol4 ,,xxxi4 p4 #ffh1 #ahgi4 ,schmalhausen1 ,j4 7#gi7 ,beitrge zur ,juraflora ,russlands4 ,mm4 ,acad4 imp4 ,st ,ptersbourg1 #g vol4 ,,xxvii4 no4 #d1 #ahgi4 ,schmitz1 ,f4 7#ig7 ,rhodophyceae4 ,engler und ,prantl2 ,die natrlichen ,pflanzenfamilien4 ,teil ,i4 ,abt4 #b4 ,leipzig1 #ahig4 ,schoenlein1 ,j4 ,l4 and ,schenk1 ,a4 7#fe7 ,abbildungen von fossilen ,pflanzen aus dem ,keuper ,frankens4 ,wiesbaden1 #ahfe4 ,schrter1 ,j4 7#hi7 ,engler und ,prantl2 ,die natrlichen ,pflanzenfamilien4 ,teil ,i4 ,abth4 #a4 #ahhi4 ,schulze1 ,c4 ,f4 7#agee7 ,kurtze ,betrachtung derer ,kruterabdrcke im ,steinreiche4 ,dresden and ,leipzig1 #agee4 ,schulze1 ,f4 7#ee7 ber das ,vorkommen wohlerhaltener ,cellulose in ,braunkohle und ,steinkohle4 ,bericht4 k4 ,preuss4 ,akad4 ,wiss4 ,berlin1 #ahee1 p4 #fgf4 ,schtt1 ,f4 7#ic7 ,das ,pflanzenleben der ,hochsee4 ,kiel and ,leipzig1 #ahic4 7,from ,hensen's ,plankton-,expedition47 ---- 7#if7 ,bacillariales4 ,engler und ,prantl2 ,die natrlichen ,pflanzenfamilien4 ,teil ,i4 ,abt4 #a4 b4 #ahif4 ,schweinfurth1 ,g4 7#hb7 ,zur ,beleuchtung der ,frage ber den versteinerten ,wald4 ,zeit4 deutsch4 geol4 ,ges4 vol4 ,,xxxiv4 p4 #aci1 #ahhb4 ,schwendener1 ,s4 7#gd7 ,das mechanische ,princip im anatomischen ,bau der ,monocotylen4 #ahgd4 ,scott1 ,d4 ,h4 7#id7 7#ie7 7#if7 ,vide ,williamson1 ,w4 ,c4 ---- 7#if7 ,an introduction to structural ,botany4 ,pt4 ,,ii4 ,flowerless plants4 ,london1 #ahif4 ---- 7#if7 ,presidential address4 7,liverpool ,meeting47 ,british ,assoc4 ,report1 p4 #iib1 #ahif4 ---- 7#ig7 ,on the structure and affinities of fossil plants from the ,palaeozoic rocks4 ,on ,cheirostrobus1 a new type of fossil cone from the ,lower ,carboniferous strata 7,calciferous ,sandstone ,series74 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxxxix4 ,b4 p4 #a1 #ahig4 ,seeman1 ,b4 7#fe7 ,a gigantic ,equisetum4 ,journ4 ,bot4 vol4 ,,iii4 p4 #abc1 #ahfe4 ,seward1 ,a4 ,c4 7#hh7 ,on ,calamites undulatus4 ,geol4 ,mag4 vol4 ,v4 p4 #bhi1 #ahhh4 ---- 7#hi7 ,sphenophyllum as a branch of ,asterophyllites4 ,mem4 and ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 ,,iii4 #d p4 #a1 #ahhi-ij4 ---- 7#id7 ,algae as rock-building organisms4 ,science ,progress1 vol4 ,,ii4 no4 #g1 p4 #aj1 #ahid4 ---- 7#id7 ,catalogue of the ,mesozoic plants in the ,department of ,geology1 ,british ,museum4 ,the ,wealden ,flora1 ,pt4 ,i4 ,london1 #ahid4 ---- 7#ie7 ,ibid4 ,pt4 ,,ii4 ,london1 #ahie4 ---- 7#ie7 ,coal3 its structure and formation4 ,science ,progress1 vol4 ,,ii4 p4 #cee1 #ahie4 ---- 7#ie7 ,notes on ,pachytheca4 ,proc4 ,phil4 ,soc4 ,cambridge1 vol4 ,,viii4 pt4 #e1 p4 #bgh1 #ahie4 ---- 7#if7 ,notes on the geological history of ,monocotyledons4 ,annals ,bot4 vol4 ,x4 p4 #bje1 #ahif4 ---- 7#if7 ,vide ,feilden1 ,h4 ,w4 ---- 7#ig7 ,on ,cycadeoidea gigantea1 a new ,cycadean stem from the ,purbeck beds of ,portland4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,liii4 p4 #bb1 #ahig4 ---- 7#ig7 ,on the association of ,sigillaria and ,glossopteris in ,south ,africa4 ,ibid4 p4 #cae1 #ahig4 ,sharpe1 ,s4 7#fh7 ,on a remarkable incrustation in ,northamptonshire4 ,geol4 ,mag4 vol4 ,v4 p4 #efc1 #ahfh4 ,sherborn1 ,c4 ,d4 7#ic7 ,an index to the genera and species of the ,foraminifera4 ,smithsonian ,miscellaneous ,collections1 #hef4 ,washington1 #ahic4 ,shrubsole1 ,w4 ,h4 and ,kitton1 ,f4 7#ha7 ,the ,diatoms of the ,london ,clay4 ,journ4 ,r4 ,mic4 ,soc4 #b vol4 ,i4 p4 #cha1 #ahha4 ,skertchly1 ,j4 ,b4 ,j4 7#gg7 ,the geology of the ,fenland4 ,mem4 ,geol4 ,surv4 #ahgg4 ,smith1 ,w4 ,g4 7#gg7 ,a fossil ,peronospora4 ,gard4 ,chron4 ,oct4 #bj1 #ahgg1 p4 #dii4 ,sollas1 ,w4 ,j4 7#hf7 ,on a specimen of slate from ,bray-,head traversed by the structure known as ,oldhamia radiata4 ,proc4 ,r4 ,soc4 ,dublin 7,n4,s47 vol4 ,v4 pp4 #cee1 #ceh1 #ahhf-hg4 ,solms-,laubach1 ,graf zu4 7#ha7 ,die corallinen ,algen des ,golfes von ,neapel und der augrenzenden ,meeres-,abschnitte4 ,fauna und ,flora des ,golfes von ,neapel1 vol4 ,,iv4 ,leipzig1 #ahha4 ---- 7#ia7 ,fossil ,botany4 ,oxford1 #ahia4 ---- 7#ic7 ber die ,algen-genera ,cymopolia1 ,neomeris und ,bornetella4 ,ann4 ,jard4 ,buitenzorg1 vol4 ,,xi4 p4 #fa1 #ahic4 ---- 7#ie7 ,william ,crawford ,williamson4 7,obit4 notice47 ,nature1 vol4 ,,lii4 p4 #dda1 #ahie4 ---- 7#ie7 ber ,devonische ,pflanzenreste aus den ,lenneschiefern der ,gegend von ,grfrath am ,niederrhein4 ,jahrb4 k4 preuss4 geol4 ,landesanst4 ,berlin1 #ahie1 p4 #fg4 ---- 7#ie7 ,monograph of the ,acetabularieae4 ,trans4 ,linn4 ,soc4 #b vol4 ,v4 pt4 #a4 p4 #a1 #ahie4 ---- 7#ie7 ,bowmanites ,rmeri1 eine neue ,sphenophylleen-,fructification4 ,jahrb4 k4 k4 geol4 ,reichsanst4 ,wien1 vol4 ,,xlv4 ,heft #b1 p4 #bbe1 #ahie4 ---- 7#if7 ber die seinerzeit von ,unger beschriebenen ,struktur bietenden ,pflanzenreste des ,unterculm von ,saalfeld in ,thringen4 ,abhand4 k4 ,preus4 ,geol4 ,landesanst4 7,n4,f47 ,heft ,,xxiii4 ,berlin1 #ahif4 ---- 7#ig7 ber die in den ,kalksteinen des ,culm von ,gltzisch ,falkenberg in ,schlesien enthaltenen ,structur bietenden ,pflanzenreste4 ,bot4 ,zeit4 ,heft ,,xii4 p4 #bai1 #ahig4 ,sorby1 ,h4 ,c4 7#gi7 ,presidential ,address4 ,proc4 ,geol4 ,soc4 #ahgh-gi1 p4 #ef4 ,spencer1 ,j4 7#ha7 ,astromyelon and its affinities4 ,geol4 ,polytech4 ,soc4 ,w4 ,r4 ,yorks4 #ahha1 p4 #dci4 ,sprengel1 ,a4 7#bh7 ,commentatio de ,psarolithis4 ,halle1 #ahbh4 ,stefani1 ,k4 de4 7#hb7 ,vorlufige ,mittheilung ber die rhtischen ,fossilen der apuanischen ,alpen4 ,verhand4 k4 k4 ,geol4 ,reichsanst4 ,wien1 #ahhb1 p4 #if4 ,steinhauer1 ,h4 7#ah7 ,on fossil ,reliquia of unknown vegetables in the ,coal ,strata4 ,trans4 ,phil4 ,soc4 ,america1 ,n4 ,s4 vol4 ,i4 p4 #bfe1 #ahah4 ,steinmann1 ,g4 7#hj7 ,zur ,kenntniss fossiler ,kalkalgen 7,siphoneae74 ,neues ,jahrb4 vol4 ,,ii4 p4 #acj1 #ahhj4 ,stenzel1 ,g4 7#hf7 ,rhizodendron oppoliense1 ,gpp4 ,jahresbericht4 ,schles4 ,ges4 ,vat4-,cult4 ,ergnzheft ,,lxiii4 #ahhf4 ,sternberg1 ,c4 von4 7#bj7 ,versuch einer geognostisch-botanischen ,darstellung der ,flora der ,vorwelt4 ,fasc4 ,i4 ,leipzig1 #ahbj4 ---- 7#ba7 ,ibid4 ,fasc4 ,,ii4 ---- 7#be7 ,ibid4 ,fasc4 ,,iv4 ---- 7#ch7 ,ibid4 ,fasc4 ,,viii4 ,sterzel1 ,j4 ,t4 7#hb7 ber die ,fruchthren von ,annularia ,sphenophylloides 7,zenk474 ,zeit4 deutsch4 geol4 ,ges4 vol4 ,,xxxiv4 p4 #fhe1 #ahhb4 ---- 7#hf7 ,die ,flora des ,rothliegenden im nordwestlichen ,sachsen4 ,pal4 ,abh4 ,dames und ,kayser1 vol4 ,,iii4 ,heft #d1 #ahhf4 ---- 7#ic7 ,die ,flora des ,rothliegenden im ,plauenscher ,grunde bei ,dresden4 ,abhand4 k4 ,schs4 ,ges4 ,wiss4 vol4 ,,xix4 ,leipzig1 #ahic4 ,stokes1 ,c4 7#dj7 ,notice respecting a piece of recent wood partly petrified by carbonate of lime1 with some remarks on fossil wood4 ,trans4 ,geol4 ,soc4 #b vol4 ,v4 p4 #bjg1 #ahdj4 ,stolley1 ,e4 7#ic7 ber ,silurische ,siphoneen4 ,neues ,jahrb4 vol4 ,,ii4 p4 #ace1 #ahic4 ,strasburger1 ,e4 7#ia7 ber den ,bau und die ,verrichtungen der ,leitungsbahnen in den ,pflanzen4 ,histologische ,beitrge1 ,heft ,,iii4 ,jena1 #ahia4 ,strickland1 ,h4 ,e4 and ,hooker1 ,j4 ,d4 7#ec7 ,on the distribution of organic contents of the ,ludlow bone-bed in the districts of ,woolhope and ,may ,hill4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,ix4 p4 #h1 #ahec4 ,stur1 ,d4 7#ge7 ,die ,culm-,flora4 ,heft #a4 ,die ,culm-,flora des mhrischschlesischen ,dachschiefers4 ,heft #b4 ,die ,culm-,flora des ,ostrauer und ,waldenburger ,schichten4 ,abhand4 k4 k4 geol4 ,reichsanst4 ,wien1 vol4 ,,viii4 #ahge-gg4 ---- 7#he7 ber die in ,fltzen-reiner ,steinkohle enthaltenen ,stein-,rundmassen und ,torf-,sphrosiderite4 ,jahrb4 k4 k4 geol4 ,reichsanst4 ,wien1 vol4 ,,xxxv4 ,heft #c1 p4 #fac1 #ahhe4 ---- 7#hg7 ,die ,carbon-,flora der ,schatzlarer ,schichten4 ,abt4 ,,ii4 ,die ,calamarien4 ,abhand4 k4 k4 geol4 ,reichsanst4 ,wien1 vol4 ,,xi4 ,abt4 #b1 #ahhg4 ,suckow1 ,g4 ,a4 7#aghd7 ,beschreibung einiger merkwrdigen ,abdrcke von der ,art der sogenannten ,calamiten4 ,hist4 ,comm4 ,acad4 elect4 ,sci4 litt4 ,theod4-,palat4 vol4 ,v4 p4 #cee4 ,mannheim1 #aghd4 ,tenison-,woods1 ,j4 ,e4 7#hc7 ,on the ,fossil ,flora of the ,coal deposits of ,australia4 ,proc4 ,linn4 ,soc4 ,new ,south ,wales1 vol4 ,,viii4 p4 #cg4 ,sydney1 #ahhd4 ,thiselton-,dyer1 ,w4 ,t4 7#gb7 ,on some fossil wood from the ,lower ,eocene4 ,geol4 ,mag4 vol4 ,,ix4 ,p4 #bda1 #ahgb4 ---- 7#ia7 ,note on ,mr ,barber's paper on ,pachytheca4 ,annals ,bot4 vol4 ,v4 p4 #bbc1 #ahij-ia4 ---- 7#ie7 ,presidential address4 ,brit4 ,assoc4 ,report1 ,ipswich1 p4 #hcf1 #ahie4 ,thomas1 ,k4 7#dh7 ,on the ,amber of ,east ,prussia4 ,annals ,mag4 vol4 ,,ii4 #b p4 #cfi1 #ahdh4 van ,tieghem1 ,p4 7#gg7 ,sur le ,bacillus amylobacter et son r#a;e dans le putrfaction des tissues vgtaux4 ,bull4 ,soc4 bot4 vol4 ,,xxiv4 p4 #abh1 #ahgg4 ---- 7#gi7 ,sur le ferment butyrique 7,bacillus amylobacter7 l'poque de la houille4 ,compt4 ,rend4 vol4 ,,lxxxix4 p4 #aajb1 #ahgi4 ---- 7#ia7 ,trait de ,botanique4 ,paris1 #ahia4 ,tilden1 ,j4 ,e4 7#ig7 ,on some algal characteristics of the ,yellowstone ,park4 ,bot4 ,gazette1 vol4 ,,xxiv4 p4 #aid1 #ahig4 ,treub1 ,m4 7#hh7 ,notice sur la nouvelle ,flore de ,krakatoa4 ,ann4 jard4 bot4 ,buitenzorg1 vol4 ,,vii4 p4 #bac1 #ahhh4 ,turner1 ,d4 7#aa7 ,historia ,fucorum4 ,london1 #ahaa4 ,unger1 ,f4 7#dj7 ber die ,struktur der ,calamiten und ihre ,rangordnung im ,gewchsreiche4 ,flora1 ,jahrg4 ,,xiii4 p4 #fed1 #ahdj4 ,unger1 ,f4 7#dd7 ,ein ,wort ber ,calamiten und ,schachtelhalmhnliche ,pflanzen der ,vorwelt4 ,bot4 ,zeit4 ,jahrg4 #b1 p4 #agg1 #ahdd4 ---- 7#ej7 ,genera et species ,plantarum fossilium4 ,vienna1 #ahej4 ---- 7#eh7 ,beitrge zur nheren ,kenntniss des ,leithakalkes4 ,denksch4 k4 ,akad4 ,wiss4 ,mnchen1 vol4 ,,xiv4 p4 #ac1 #aheh4 ,vaillant1 --4 7#agai7 ,caractres de quatorze genres de plantes4 ,hist4 ,acad4 ,roy4 ,sciences1 ,ann4 #agai1 p4 #i4 ,paris1 #agba4 ,vinci1 ,leonardo da4 7#hc7 ,literary works4 ,compiled and edited from the original ,,mss4 by ,j4 ,p4 ,richter4 ,london1 #ahhc4 ,vines1 ,s4 ,h4 7#ie7 ,a student's text-book of ,botany4 ,london1 #ahie4 ,vogelsang1 ,h4 7#gd7 ,die ,krystalliten4 ,bonn1 #ahgd4 ,volkmann1 ,g4 ,a4 7#agbj7 ,silesia subterranea4 ,leipzig1 #agbj4 ,wallace1 ,a4 ,r4 7#hf7 ,the ,malay ,archipelago4 ,london1 #ahhf4 ,walther1 ,j4 7#he7 ,die ,gesteinbildenden ,kalkalgen des ,golfes von ,neapel und die ,entstehung structurloser ,kalke4 ,zeit4 deutsch4 geol4 ,ges4 vol4 ,,xxxvii4 p4 #cbi1 #ahhe4 ---- 7#hh7 ,die ,korallenriffe der ,sinaihalbinsel4 ,abh4 math4 phys4 ,cl4 ,k4 ,schs4 ,ges4 vol4 ,,xiv4 #ahhh4 ,ward1 ,l4 ,f4 7#hd7 ,sketch of ,palaeobotany4 ,u4 ,s4 ,geol4 ,surv4 ,fifth ,ann4 ,report4 ,washington1 #ahhc-hd4 ---- 7#ib7 ,principles and methods of geologic correlation by means of fossil plants4 #ahib4 ---- 7#if7 ,fossil plants of the ,wealden4 ,science1 ,june #ab1 p4 #hfi1 #ahif4 ,warming1 ,e4 7#if7 ,lehrbuch der kologischen ,pflanzengeographie4 7,german edit47 ,berlin1 #ahif4 ,watelet1 ,ad4 7#ff7 ,description des plantes fossiles du ,bassin de ,paris4 ,paris1 #ahff4 ,wedl1 ,c4 7#ei7 ber die ,bedeutung der in den ,schalen von manchen ,acephalen und ,gasteropoden vorkommenden ,canle4 ,sitzbericht4 ,akad4 ,wiss4 ,wien1 vol4 ,,xxxiii4 p4 #dea1 #ahei4 ,weed1 ,w4 ,h4 7#hg7 ,the formation of ,travertine and siliceous ,sinter4 ,u4 ,s4 ,geol4 ,surv4 ,annual ,rep4 ,,ix4 #ahhg-hh4 ,weiss1 ,c4 ,e4 7#gf7 ,steinkohlen-,calamarien1 mit besonderer ,bercksichtigung ihrer ,fructificationen4 ,abhand4 geol4 ,specialkarte von ,preussen und den ,thringischen ,staaten1 ,bd4 ,,ii4 ,heft #a1 #ahgf4 ---- 7#hd7 ,steinkohlen-,calamarien4 ,ibid4 ,bd4 ,v4 ,heft #b1 #ahhd4 ,westermaier1 ,m4 and ,ambronn1 ,h4 7#ha7 ,beziehungen zwischen ,lebensweise und ,structur der ,schling- und ,kletterpflanzen4 ,flora1 #ahha1 p4 #dag4 ,wethered1 ,e4 7#ic7 ,on the microscopic structure of the ,wenlock limestone4 ,quart4 ,journ4 ,geol4 ,soc4 vol4 ,,xlix4 p4 #bcf1 #ahic4 ,whitney1 ,j4 ,d4 and ,wadsworth1 ,m4 ,e4 7#hd7 ,the ,azoic system4 ,bull4 ,mus4 ,comp4 ,zool4 ,harvard ,coll4 ,,vii4 #ahhd4 ,wille1 ,n4 7#ig7 ,die ,chlorophyceae4 ,engler und ,prantl2 ,die natrlichen ,pflanzenfamilien4 ,teil ,i4 ,abt4 #b4 ,leipzig1 #ahig4 ,williamson1 ,w4 ,c4 7#ga7 ,on the organization of the ,fossil ,plants of the ,coal-,measures4 ,memoir ,i4 ,calamites4 ,phil4 ,trans4 ,r4 ,soc4 vol4 ,,clxi4 p4 #dgg1 #ahga4 ---- 7#ga7 ,on the structure of the woody zone of an undescribed form of ,calamite4 ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 ,,iv4 #c p4 #aee1 #ahga4 ---- 7#ga7 ,on a new form of ,calamitean ,strobilus from the ,lancashire ,coal-,measures4 ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 ,,iv4 #c p4 #bdh1 #ahga4 ---- 7#gc7 ,on the organization1 c4 ,mem4 ,,iv4 ,dictyoxylon1 ,lyginodendron and ,heterangium4 ,phil4 ,trans4 vol4 ,,clxiii4 p4 #cgg1 #ahgc4 ---- 7#gd7 ,ibid4 ,mem4 ,v4 ,asterophyllites4 ,phil4 ,trans4 vol4 ,,clxiv4 p4 #da1 #ahgd4 ---- 7#gf7 ,on the organization of ,volkmannia ,dawsoni1 an undescribed verticillate strobilus from the ,lower ,coal-,measures of ,lancashire4 ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 ,v4 #c p4 #bh1 #ahgf4 ---- 7#gh7 ,on the organization1 c4 ,mem4 ,,ix4 ,phil4 ,trans4 vol4 ,,clxix4 p4 #cai1 #ahgh4 ---- 7#hj7 ,ibid4 ,mem4 ,x4 ,phil4 ,trans4 vol4 ,,clxxi4 p4 #dic1 #ahhj4 ---- 7#ha7 ,ibid4 ,mem4 ,,xi4 ,phil4 ,trans4 vol4 ,,clxxii4 p4 #bhc1 #ahha4 ---- 7#hb7 ,helophyton ,williamsonis4 ,nature1 vol4 ,,xxv4 p4 #abd1 #ahhb4 ---- 7#hc7 ,on some anomalous ,oolitic and ,palaeozoic forms of vegetation4 ,r4 ,instit4 ,great ,britain4 7,weekly ,evening ,meeting71 ,feb4 #af1 #ahhc4 ---- 7#hc7 ,on the organization1 c4 ,mem4 ,,xii4 ,phil4 ,trans4 vol4 ,,clxxiv4 p4 #dei1 #ahhc4 ---- 7#he7 ,on some undescribed tracks of invertebrate animals from the ,yoredale rocks4 ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 ,x4 #c p4 #ai1 #ahhe4 ---- 7#hg7 ,a monograph of the morphology and histology of ,stigmaria ficoides4 ,palaeont4 ,soc4 ,london1 #ahhg4 ---- 7#hg7 ,on the relations of ,calamodendron to ,calamites4 ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 ,x4 #c p4 #bee1 #ahhg4 ---- 7#hh7 ,on some anomalous cells developed within the interior of the vascular and cellular tissues of the fossil plants of the ,coal-,measures4 ,annals ,bot4 vol4 ,i4 #cae1 #ahhh4 ---- 7#hh7 ,on the organisation c4 ,mem4 ,,xiv4 ,the true fructification of ,calamites4 ,phil4 ,trans4 vol4 ,,clxxix4 p4 #dg1 #ahhh4 ---- 7#hi7 ,ibid4 ,mem4 ,,xv4 ,phil4 ,trans4 vol4 ,,clxxx4 p4 #aee1 #ahhi4 ---- 7#ia7 ,general1 morphological and histological ,index to the ,author's ,collective ,memoirs on fossil plants of the ,coal-,measures4 ,pt4 ,i4 ,proc4 ,lit4 ,phil4 ,soc4 ,manchester1 vol4 ,,iv4 #c #ahia4 ---- 7#ia7 ,on the organisation c4 ,mem4 ,,xviii4 ,phil4 ,trans4 vol4 ,,clxxxii4 ,b4 p4 #bee1 #ahia4 ---- 7#ib7 ,the genus ,sphenophyllum4 ,nature1 vol4 ,,xlvii4 p4 #aa1 #ahib4 ---- 7#if7 ,reminiscences of a ,yorkshire ,naturalist 7edited by ,mrs ,crawford ,williamson74 ,london1 #ahif4 ,williamson1 ,w4 ,c4 and ,scott1 ,d4 ,h4 7#id7 ,further observations on the organisation of the fossil plants of the ,coal-,measures4 ,pt4 ,i4 ,calamities1 ,calamostachys and ,sphenophyllum4 ,phil4 ,trans4 vol4 ,,clxxxv4 p4 #hfc1 #ahid4 ---- 7#ie7 ,ibid4 ,pt4 ,,ii4 ,the roots of ,calamites4 ,phil4 ,trans4 vol4 ,,clxxxvi4 p4 #fhc1 #ahie4 ---- 7#if7 ,ibid4 ,pt4 ,,iii4 ,lyginodendron and ,heterangium4 ,phil4 ,trans4 vol4 ,,clxxxvi4 p4 #gjc1 #ahif4 ,wilson1 ,j4 ,s4 ,g4 7#hg7 ,the ,diatomite of ,cuithir4 ,min4 ,mag4 vol4 ,,vii4 p4 #ce1 #ahhg4 ,witham1 ,h4 7#ca7 ,a description of a fossil tree discovered in the quarry at ,craigleith near ,edinburgh4 ,nat4 ,hist4 ,soc4 ,northumberland1 ,durham and ,newcastle-on-,tyne1 #ahca4 ---- 7#cc7 ,the internal structure of fossil vegetables found in the ,carboniferous and ,oolitic deposits of ,great ,britain4 ,edinburgh1 #ahcc4 ,woodward1 ,h4 7#gb7 ,a monograph of the ,british fossil ,crustacea belonging to the order ,merostomata4 ,palaeont4 ,soc4 #ahff-gh4 ,woodward1 ,h4 ,b4 7#hg7 ,the ,geology of ,england and ,wales4 ,london1 #ahhg4 ---- 7#ie7 ,the ,jurassic rocks of ,britain4 ,mem4 ,geol4 ,surv4 vol4 ,v4 #ahie4 ,woodward1 ,j4 7#afie7 ,an essay toward a ,natural ,history of the ,earth4 ,london1 #afie4 ---- 7#agbh7 ,a catalogue of the additional ,english fossils in the collection of ,j4 ,woodward1 ,m4,a4 ,london1 vol4 ,,ii4 #agbh4 ---- 7#agbi7 ,an attempt towards a ,natural ,history of the fossils of ,england2 in a catalogue of the ,english fossils in the collection of ,j4 ,woodward1 ,m4,a4 ,london1 vol4 ,i4 #agbi4 ,young1 ,g4 and ,bird1 ,j4 7#bb7 ,a ,geological ,survey of the ,yorkshire ,coast4 ,whitby1 #ahbb4 ,young1 ,j41 ,glen1 ,d4 ,c4 and ,kidston1 ,r4 7#hh7 ,notes on a section of ,carboniferous strata containing erect stems of fossil trees c4 in ,victoria ,park1 ,whiteinch4 ,trans4 ,geol4 ,soc4 ,glasgow1 vol4 ,,viii4 p4 #bbg1 #ahhh4 ,zeiller1 ,r4 7#hj7 ,vgtaux du terrain houiller de la ,france4 ,l'explication de la carte gologique de la ,france1 vol4 ,,iv4 ,paris1 #ahhj4 ---- 7#hb7 ,observations sur quelques cuticles fossiles4 ,ann4 ,sci4 ,nat4 vol4 ,,xiii4 #f p4 #bag1 #ahhb4 ---- 7#hd7 ,sur des traces d'insectes simulant des empreintes vgtales4 ,bull4 ,soc4 ,gol4 ,france1 #c vol4 ,,xii4 p4 #fgf1 #ahhd4 ---- 7#hh7 ,bassin houiller de ,valenciennes4 ,description de la flore fossile4 tudes ,gtes ,min4 ,france4 ,paris1 #ahhh4 ---- 7#hh7 ,vide ,renault1 ,b4 ---- 7#ia7 ,sur la valeur du genre ,trizygia4 ,bull4 ,soc4 ,gol4 ,france1 vol4 ,,xix4 #c p4 #fgc1 #ahia4 ---- 7#ib7 ,sur les empreintes du sondage de ,douvres4 ,compt4 ,rend4 ,oct4 #bd1 #ahib4 ---- 7#ib7 ,bassin houiller et permien de ,brive4 tudes ,gtes ,min4 ,france4 ,paris1 #ahib4 ---- 7#ic7 tude sur la constitution de l'appareil fructificateur des ,sphenophyllum4 ,mm4 ,soc4 ,gol4 ,france1 #ahic1 p4 #c4 ---- 7#id7 ,note sur la flore des ,couches permiennes de ,trienbach 7,alsace74 ,bull4 ,soc4 ,gol4 ,france1 vol4 ,,xxii4 #c p4 #aic1 #ahid4 ---- 7#ie7 ,notes sur la flore des ,gisements houillers de la ,rhune et d',ibantelly 7,basses-,pyrnes74 ,bull4 ,soc4 ,gol4 ,france1 vol4 ,,xxiii4 #c p4 #dhb1 #ahie4 ---- 7#ie7 ,sur la flore des dpts houillers d',asie ,mineure et sur la prsence1 dans cette flore1 du genre ,phyllotheca4 ,compt4 ,rend4 vol4 ,,cxx4 p4 #abbh1 #ahie4 ---- 7#if7 ,remarques sur la flore fossile de l',alta4 ,bull4 ,soc4 ,gol4 ,france1 vol4 ,,xxiv4 #c p4 #dff1 #ahif4 ,zenker1 ,f4 ,c4 7#cc7 ,beschreibung von ,galium sphenophylloides4 ,neues ,jahrb4 ,min4 #ahcc1 p4 #cih4 ,zigno1 ,a4 de 7#ef7 ,flora fossilis formationis ,oolithicae4 ,vol4 ,i4 ,padova1 #ahef4 ,,index4 ,acetabularia1 #afe1 #aff ,a4 mediterranea1 #afb1 #afe1 #aff ,achyla1 #abg ,acicularia1 #afb1 #aff1 #afg ,a4 ,andrussowi1 #afb1 #afh ,a4 miocenica1 #afb1 #afh ,a4 pavantina1 #afg ,a4 ,schencki1 #afb1 #aff1 #afh ,aegoceras planicosta1 #fa ,aeolian rocks1 #be ,aeschynomene1 #dad ,africa1 ,south1 #hj1 #bhd ,agaricus melleus1 #baa1 #bab1 #bae ,algae1 #ach-bjb ,algites1 #adh1 #adi1 #bjd1 #bje ,amazons1 #ff ,amber1 #gj1 #ga1 #bjf1 #baa1 #bba1 #bee ,america1 #ahb ,amphiroa1 #ahd ,anarthrocanna1 #bhc ,a4 tuberculata1 #chf ,andersson1 ,g41 #fj ,andrae1 ,k4 ,j41 #bgf ,andreaeales1 #bcf ,andrussow1 ,n41 #afh ,annularia1 #bee1 #bfj1 #bhb1 #bhc1 #bhi1 #cbi1 #ccb1 #ccc1 #ccf-cci1 #cdj1 #cfa1 #cfb1 #cgi1 #cha ,a4 calamitoides1 #cce ,a4 ,geinitzi1 #cch ,a4 longifolia1 #cch1 #cda ,a4 radiata1 #bhc ,a4 ramosa1 #cfc ,a4 sphenophylloides1 #cdj1 #cda1 #cfc ,a4 stellata1 #cch-cda1 #cfc ,a4 westphalica1 #cch ,antigua1 #gi ,aphlebia1 #adb ,araucaria imbricata1 #aja1 #ajd ,araucarioxylon ,withami1 #ha1 #hb ,archaean system1 #cd-cf ,archaeocalamites1 #bed1 #bee1 #bef1 #bfc1 #bhe1 #ccf1 #chc-chh ,a4 scrobiculatus1 #che-chg d',archiac1 ,a41 #aff1 #afg ,arctic plants1 #af1 #ag ,arenig series1 #cg ,arran1 #hh1 #hi ,arthrodendron1 #cja1 #cjb1 #cbd1 #cbe1 #cbf1 #cbg1 #cff1 #cgi1 #cha ,arthropitys1 #cjj1 #cja1 #cjb1 #cjd1 #caa1 #cbd1 #cbe1 #cbf1 #cbh1 #ccc1 #cdi1 #cfi1 #cge1 #cgi1 #chj1 #cha1 #chd ,a4 approximata1 #cga ,a4 bistriata1 #cbf ,arthropod eggs1 #ajh ,artis1 ,f4 ,t41 #d1 #ajd1 #big ,artisia1 #ajd ,ascomycetes1 #bjh1 #bji1 #bbj ,asia ,minor1 ,coal-,measures of1 #bhb1 #bhc ,asterocalamites scrobiculatus1 #chf ,asterophyllites1 #bfd1 #bgf1 #cbi1 #ccb1 #ccc1 #cch1 #cfi1 #cga1 #cgi1 #cig1 #dji ,a4 elegans1 #chf ,a4 equisetiformis1 #cce1 #cch ,a4 insignis1 #cig ,a4 longifolius1 #cch ,a4 spaniophyllus1 #chf ,a4 sphenophylloides1 #cig ,astromyelon1 #cdb1 #cdc1 #cha ,australia1 #agi1 #bij1 #bia ,autun1 #f1 #df1 #hc1 #agi1 #aha1 #ahb1 #bjf1 #cij1 #cii ,azoic system1 #cf ,bacillariaceae1 #aej-aef ,bacillus1 #ace1 #acf ,b4 amylobacter1 #acf ,b4 permicus1 #ace ,b4 ,tieghemi1 #ace1 #acf ,bacteria1 #ge1 #acb1 #ach ,bactryllium1 #aed-aef ,b4 deplanatum1 #aee ,bala series1 #cg ,balanoglossus1 #ade ,balfour1 ,bayley1 #agh ,balfour1 ,j4 ,h41 #aja ,bambusa arundinacea1 #cbb ,barbados1 #ahh ,barber1 ,c4 ,a41 #aic1 #aig1 #aih1 #bjc1 #bjd ,barrois1 ,c41 #adf ,barton1 ,r41 #hj de ,bary1 ,a41 #acb ,basidiomycetes1 #bjh1 #baa1 #bab ,bates1 ,h4 ,w41 #fd1 #ff ,bauhin1 ,c41 #bbe ,bear ,island1 #cff ,bentham1 ,g41 #ih1 #ii ,bergeria1 #aja ,bernician series1 #dc ,bertrand1 ,c4 ,e41 #hg1 #aed1 #agh1 #aha ,beyrich1 ,e41 #eb ,bilin1 #aeb ,bilobites1 #adh ,binney1 ,e4 ,w41 #i1 #aj1 #cjd1 #caa1 #cdc1 #cea1 #chf1 #dja ,bituminous deposits1 #agh-ahc ,blackman1 ,v4 ,h41 #aai1 #abj ,blandowia1 #bca ,boghead1 #agh-ahc ,boring algae1 #abg1 #abh ,boring fungi1 #abg1 #abh ,bornemann1 ,j4 ,g41 #abi1 #acj1 #adh1 #agg ,bornet1 ,e41 #aha ,bornet1 ,e4 and ,flahault1 #abh1 #abi ,bornetella1 #agg ,bornia1 #bfc ,b4 equisetiformis1 #cce ,b4 scrobiculata1 #chf ,b4 stellata1 #cch ,bostrychus1 #baj1 #baa ,bothrodendron1 #acc1 #acd ,botrydium1 #aeg ,bowmanites1 #dja1 #djb ,b4 ,dawsoni1 #dja ,b4 ,germanicus1 #djh ,brazil1 #gi ,brodie1 ,p4 ,b41 #bdj ,brongniart1 ,a41 #e1 #f1 #i1 #aa1 #ag1 #ah1 #aaa1 #aab1 #ade1 #agg1 #bcc1 #bfi1 #bha1 #bhh1 #bhi1 #bia1 #big1 #bii1 #cjj1 #cja1 #ccb1 #ccf1 #cea1 #cij1 #cia ,bronn1 ,h4 ,g41 #aah ,brora1 #bfi ,brown1 ,a41 #ahi1 #aij ,brukmannia1 #cej1 #cfj1 #cfa ,bryales1 #bcf ,bryophyta1 #bbi-bda1 #bdc ,bryozoa1 #ahg ,buccinum1 #aei ,buckman1 ,j41 #bdj1 #bgh ,bunbury1 ,sir ,c4 ,j4 ,f41 #bgj1 #bga1 #bgc1 #bhd1 #bhg1 #bhh1 #bhi ,bunter series1 #dg1 #bfg1 #bib1 #bic ,burntisland1 #hh1 #ij1 #cig ,buthotrephis radiata1 #cch ,bzistock1 #bh ,calamarieae1 #bee1 #bie-chh ,calamitea1 #bih1 #cjj1 #cja1 #cjc ,c4 bistriata1 #cja ,calamites1 #ah1 #ai1 #gg1 #hf1 #id1 #ajd1 #aad1 #beb1 #bed-beg1 #bei1 #bfj1 #bfb1 #bfd1 #bfi1 #bhe1 #bhf1 #bhi1 #bie-chc1 #chf-chh1 #dac ,calamites1 sub-genera of1 #cha ,c4 alternans1 #cgh ,c4 approximatus1 #cfi1 #cgj1 #cgd1 #cgh ,c4 arborescens1 #cfc ,c4 ,beani1 #bgj1 #bgc ,c4 cannaeformis1 #cgd ,c4 communis1 #cbf1 #cea ,c4 cruciatus1 #cgf-cgh ,c4 decoratus1 #cgd ,c4 equisetiformis1 #cce ,c4 giganteus1 #bga ,c4 gigas1 #bga ,c4 ,gpperti1 #cfh1 #cgb-cgd ,c4 lateralis1 #bgf ,c4 laticulatus1 #chf ,c4 obliquus1 #chf ,c4 pedunculatus1 #ceh ,c4 ramosus1 #cfc ,c4 ,sachsei1 #cgb ,c4 scrobiculatus1 #chf ,c4 ,suckowi1 #cgb1 #cgd1 #cge ,c4 transitionis1 #chf ,c4 varians1 #cga ,c4 variolatus1 #chf ,c4 verticillatus1 #cgb ,calamitina1 #bfj1 #bff1 #bfg1 #cbi1 #ccj1 #cfb1 #cfd1 #cfe1 #cfg-cgf1 #cha1 #chc1 #chh ,c4 pauciramis1 #cfg ,calamocladus1 #bbg1 #bhi1 #cbh1 #cbi1 #ccb1 #ccc1 #ccf1 #ccg1 #cej1 #cfa-cfd1 #cha1 #dji ,c4 equisetiformis1 #ccc-cce1 #cfc ,c4 frondosus1 #bhi ,calamodendron1 #cjj-cjb1 #cbh1 #cdi1 #cfd1 #cge1 #cgh1 #cgi1 #chj1 #chb ,c4 bistriatum1 #cjj ,c4 commune1 #caa1 #cag ,c4 cruciatum1 #cgh ,c4 intermedium1 #cbh ,c4 striatum1 #cjj ,calamophyllites1 #cga ,c4 ,gpperti1 #cgb ,calamopitys1 #cja1 #cjb1 #cha ,calamostachys1 #cci1 #cdb1 #cej1 #cea-ceg1 #cfb1 #cga1 #cgi1 #cha1 #chd1 #chg1 #djb ,c4 ,binneyana1 #cea-cee1 #cef1 #ceg1 #cfa ,c4 calathifera1 #cda1 #cfc ,c4 ,casheana1 #cee-ceg1 #cfa ,c4 longifolia1 #cfc ,c4 ramosa1 #cfc ,c4 ,solmsi1 #cfc1 #cfd ,c4 tenuissima1 #bfa ,c4 tuberculata1 #cfc ,calciferous sandstone1 #dc1 #adh1 #cig1 #dab ,callus wood1 in ,calamites1 #cai1 #cbj ,calothrix1 #abf ,cambrian1 #cf1 #cg1 #adi1 #agg de ,candolle1 ,a41 #big ,carboniferous limestone1 #dj1 #db1 #dc1 #chg ,carboniferous system1 #ci-de ,carinal canals1 #bdi1 #cjf1 #cjg1 #cjh ,carlsbad1 #abc1 #abf ,carpenter1 ,w4 ,b41 #afg ,carpolithus1 #bhj ,carruthers1 ,w41 #i1 #aj1 #hg1 #aic1 #aig1 #bjb1 #bab1 #bag1 #bdj1 #cjd1 #cea ,cash1 ,w4 and ,hick1 ,t41 #bjf1 #bah1 #bai1 #cdb ,castracane1 ,f41 #aed ,casuarina stricta1 #ie1 #if ,casuarinites1 #ccb ,c4 equisetiformis1 #cce ,c4 stellata1 #cch ,caterpillars1 ,liassic1 #bdj ,caulerpa1 #aeg-aei ,c4 abies-marina1 #adb ,c4 cactoides1 #adb1 #aeh ,c4 ,carruthersi1 #aei ,c4 ericifolia1 #adb ,c4 plumaris1 #adb ,c4 pusilla1 #adb ,c4 scalpelliformis1 #adb ,c4 taxifolia1 #adb ,caulerpaceae1 #aeg-aei ,caulerpites1 #adb1 #aeh ,c4 cactoides1 #aeh ,celastrum1 #aha ,celluloxylon primaevum1 #aih ,ceratium1 #aag ,chalk1 #bf1 #ej1 #abj ,challenger1 ,h4 ,m4 ,s41 #fe1 #ff1 #aja1 #aag1 #aah1 #aai1 #abb1 #aea ,chara1 #fi1 #bbc1 #bbh ,c4 ,bleicheri1 #bbf ,c4 foetida1 #bbd1 #bbe ,c4 ,jaccardi1 #bbf ,c4 ,knowltoni1 #bbd1 #bbf1 #bbg ,c4 ,wrighti1 #bbf1 #bbg ,charace1 #bbb-bbh ,chareae1 #bbc-bbh ,charophyta1 #bbb-bbh ,cheirostrobus1 #beh1 #dac ,c4 ,pettycurensis1 #dab ,chert1 #bbg ,chlorophyceae1 #abg-acj1 #aef-aij ,chondrites1 #adb1 #add ,c4 plumosa1 #adh ,c4 verisimilis1 #adf1 #adg ,chondrus1 #bca ,c4 crispus1 #aia ,chroococcaceae1 #abb1 #abc1 #aha ,church1 ,a4 ,h41 #aga ,chytridineae1 #baf ,cingularia1 #bij1 #cfd ,cladochytrium1 #baf ,cladosporites bipartitus1 #bag1 #bbj ,clayton1 fossil tree1 #ga ,coal1 #dd1 #de1 #fh1 #gf1 #ib1 #acc1 #acd1 #agh1 #agi ,coal-balls1 #he1 #hf ,coalbrook ,dale1 #cfa ,coal-,measures1 #dj-de1 #ee1 #hd1 #he1 #bag1 #bch1 #bef1 #bei1 #bfa1 #bfh1 #bhb1 #bhc1 #bif1 #cja1 #cjb1 #cbe1 #cbi1 #ceh1 #cge1 #cgf1 #cgh1 #chb1 #cig1 #dja1 #djf1 #dac ,coccoliths1 #abj ,coccospheres1 #aah-aba ,codiaceae1 #aei-afd ,codium1 #aei1 #afj ,c4 ,bursa1 #afj ,c4 tomentosum1 #afj ,coelotrochium1 #agf ,coemans1 ,e4 and ,kickx1 ,j4 ,j41 #daa ,coenocyte1 #aaf1 #aag ,cohn1 ,f41 #abc1 #abf ,cole1 ,g41 #hc ,cone-in-cone structure1 #hc ,confervites1 #agg ,c4 chantransioides1 #agh ,confervoideae1 #agg-agh ,conglomerate1 #bd ,coniferae1 #bcb ,convallarites1 #bia ,conwentz1 ,h41 #hj1 #baa1 #bab1 #bba ,cook1 ,capt41 #abb ,coprolites1 #ajh1 #ace1 #acg1 #ahb ,coral reefs1 #bf1 #dj1 #dh ,corallina officinalis1 #ahc1 #ahd ,corallinaceae1 #ahc-aij ,corallineae1 #ahd ,corallines1 #aei1 #afi1 #ahd ,coralliodendron1 #afc ,corals1 fossil1 #be ,corda1 ,a4 ,j41 #e1 #h ,cordaites1 #ge1 #hj1 #ii1 #ajd1 #cff ,cormack1 ,b4 ,g41 #bea1 #beb ,coscinodiscus1 #aec ,costa1 ,mendes da1 #c ,cotta1 ,c4 ,b41 #i1 #bih #8,crag'1 #ec1 #fb ,craigleith ,quarry1 ,edinburgh1 #ha ,cramer1 ,c41 #aga1 #agg ,credner1 ,h41 #adi ,crpin1 ,f41 #aji ,cretaceous system1 #ej1 #ea1 #ahh ,cromer ,forest bed1 #ec ,crossochorda1 #adh ,cruziana1 #add1 #ade ,culm rocks1 #db1 #fh1 #chc1 #dac ,cuticles1 fossil1 #fh1 #acc ,cyanophyceae1 #aba1 #abb-acb ,cyathophyllum bulbosum1 #bcg ,cycadace1 #ih ,cycadeoidea gigantea1 #hh1 #bad ,cycadorachis1 #aad1 #aae ,cycads1 #di1 #ef1 #ii1 #bha ,cyclocladia1 #cga ,c4 major1 #cgb ,cymopolia1 #afe1 #afi1 #agj1 #agb1 #agg ,c4 barbata1 #afb1 #afi1 #aga ,c4 elongata1 #agb ,c4 ,mexicana1 #afi ,dactylopora1 #age1 #agf ,d4 cylindracea1 #agf ,dactyloporella1 #agf ,darwin1 ,c41 #af1 #ag1 #fe1 #gj1 #gi1 #ajj ,dasycladaceae1 #afd-agf ,dasyporella1 #agf ,dawes1 ,j4 ,s41 #big1 #cjb ,dawson1 ,sir ,w41 #adg1 #aib1 #aic1 #aie1 #cch1 #cij1 #dac ,dawsonia1 #bcg ,d4 polytrichoides1 #bcg ,d4 superba1 #bcg ,decorticated stems1 #aje ,deecke1 ,w41 #agc ,defrance1 ,j4 ,l4 ,m41 #agb ,dendrophycus triassicus1 #adf ,denudation1 #bc1 #bd1 #ce ,desmideae1 #bba ,devonian system1 #ci1 #acc1 #agc1 #aic1 #aie1 #bbe1 #bef1 #cch1 #chc1 #dac ,diatomaceae1 #aej-aef ,diatomite1 #aea ,diatoms1 #aag1 #aah1 #abc1 #ada1 #ahe ,dichothrix1 #abc ,dicotyledons1 #ih1 #ii ,dictyogens1 #ii ,dinoflagellata1 #aah ,diplopora1 #agc-agf ,dirt-beds1 of ,portland1 #ef1 #eg ,dismal swamp1 #gd ,dixon1 ,h4 ,n4 and ,joly1 ,j41 #abj ,dorset1 coast1 #ef1 #bbf ,dover coal1 #de ,drifting of trees c41 #fd ,duncan1 ,m41 #abg1 #abi ,duval-jouve1 ,j41 #bdg ,dyas system1 #df1 #bji ,echinoid spines1 #agg ,ehrenberg1 ,c4 ,g41 #aag1 #aah1 #aea1 #aec ,elaters1 #bde ,ellis1 ,j41 #aei1 #afi ,endophytic algae1 #acb ,eocene rocks1 #bi1 #eb1 #afd1 #aga ,eophyton1 #add1 #adh ,eopteris ,morierei1 #ajf ,ephedra distachya1 #ie1 #ig ,equisetaceae1 #ai1 #bdd-bed1 #bee1 #bef ,equisetales1 fossil1 #bed-chh ,equisetales1 recent1 #bdd-bed ,equisetites1 #bed1 #beg-bgc1 #bhb1 #bia1 #ccj1 #dac ,e4 arenaceus1 #bfh1 #bfi1 #bge1 #bhj ,e4 ,beani1 #bgj-bge ,e4 ,brodii1 #bgh ,e4 ,burchardti1 #bgi1 #bhj ,e4 ,burejensis1 #bhj ,e4 columnaris1 #gb1 #bfe1 #bfi-bga ,e4 ,gpperti1 #chf ,e4 ,hemingwayi1 #bei1 #bfb-bfd ,e4 lateralis1 #bfe1 #bge-bgi ,e4 ,monyi1 #bff ,e4 ,mougeoti1 #bfg ,e4 ,mnsteri1 #bgh1 #bgi ,e4 ,parlatori1 #bhj ,e4 platyodon1 #bfg ,e4 rotiferum1 #bgi ,e4 spatulatus1 #bfd1 #bfe ,e4 ,vaujolyi1 #bfa ,e4 ,yokoyamae1 #bhj ,e4 zeaeformis1 #bfe-bff ,equisetum1 #ai1 #bde-bed1 #beh1 #bfb1 #bfc1 #bfg1 #bfh1 #bha1 #bhb1 #bhe1 #bhf1 #bhg1 #bij1 #bib1 #big1 #bih1 #cjd1 #cjg1 #cjh1 #cji1 #cbg1 #ccg1 #cdf1 #cfj1 #cha1 #chd1 #chh1 #cij ,e4 arvense1 #bdf1 #bdg1 #bea1 #bgi ,e4 debile1 #ie1 #if1 #ig ,e4 giganteum1 #bde1 #big ,e4 hiemale1 #bgj ,e4 limosum1 #bfc ,e4 litorale1 #bec ,e4 maximum1 #bde1 #bdf1 #bdg1 #bej-bec ,e4 palustre1 #bdg1 #bec ,e4 ramosissimum1 #bei1 #bfe1 #bgj ,e4 sylvaticum1 #bdg1 #bgi ,e4 ,telmateia1 #bde ,e4 trachyodon1 #bgj ,e4 variegatum1 #ie1 #beb ,e4 xylochaetum1 #bej ,eryngium ,lassauxi1 #ii ,e4 montanum1 #ii ,etheridge1 ,r41 #bjj1 #bae1 #bij ,ettingshausen1 ,c4 von1 #f1 #g1 #caa1 #ccb1 #cgb ,eucalamites1 #cfg1 #cgf1 #cgi ,eurypterus1 #cga ,e4 mammatus1 #cga ,feilden1 ,col4 ,h4 ,w41 #baa ,feistmantel1 ,o41 #bhd1 #bia1 #bic1 #chg ,felix1 ,j41 #cii ,fischer1 ,a41 #bag ,fish-scales1 #abg1 #ahb ,fleurs d'eau1 #acb1 #ahb ,fliche1 ,p4 and ,bleicher1 #bcb ,flint1 #fb ,florideae1 #age1 #ahc-aij ,flowers1 fossil1 #gj ,flysch1 #adg1 #adh1 #aib ,fontinalis1 #bdj ,foraminifera1 #bf1 #afa1 #afc1 #age1 #ahe ,forbes1 ,e41 #af ,forbes1 ,h4 ,o41 #fc ,forest-bed1 #ec ,forests1 fossil1 #ef ,fossil1 meaning of term1 #fg ,fossil plants1 determination of1 #ic-aji ,fossil trees1 #gd1 #gi1 #hj ,fossils in half-relief1 #gg ,fracastaro1 #b ,freeman1 ,e4 ,j41 #bc ,frullania1 #bcf ,frustules of ,diatoms1 #aej ,fuchs1 ,t41 #aei1 #afd ,fucoides1 #adb1 #aia ,f4 erectus1 #bcc ,fucoids1 #hg1 #adg1 #adh ,fucus1 #aia1 #aib1 #bjb1 #bca ,f4 crispus1 #aia ,funafuti ,island1 #ahd ,fungi1 #bjg-bbb1 #cje ,galium1 #cch1 #chi ,g4 sphenophylloides1 #cda ,gallionella1 #aec ,gardiner1 ,stanley1 #ahd ,gardner1 ,starkie1 #eh1 #bdj1 #bgc ,geikie1 ,sir ,a41 #ci ,geinitz1 ,h4 ,b41 #djh ,geological evolution1 #ec ,geological history1 #bb-ec ,germar1 ,e4 ,f41 #big1 #dji ,geysers1 #ib1 #abf ,ginkgo1 #eh1 #baj1 #cij ,g4 biloba1 #ae ,girvanella1 #abd-abf1 #afj ,globigerine ooze1 #aah ,glocapsa1 #abb1 #acj ,glotheca1 #abb ,gloioconis1 #acj ,glossopteris ,browniana1 #ahb ,glossopteris ,flora1 #bia1 #bid ,gomphonema1 #aec ,gomphosphaeria1 #aha ,gondwana system1 #df-dg1 #hd1 #bhh1 #bib1 #daa ,gondwana ,land1 #bid ,goniada maculata1 #adc1 #add ,goniolina1 #agf1 #agg ,gppert1 ,h4 ,r41 #a1 #i1 #adf1 #bhc1 #bhd1 #cjj1 #cja1 #cjd1 #chf1 #chg ,gppert and ,berendt1 #bce ,gppert and ,menge1 #bjf ,gottsche1 #bcf ,gottschea1 #bcg ,gramineae1 #bgc ,grand',croix1 #hj1 #acg ,grand',eury1 ,c41 #aja1 #bfa1 #bfb1 #bhi1 #caf1 #ccb1 #ccf1 #cdc1 #cga1 #cge1 #cha ,gray1 ,asa1 #af ,greensand rocks1 #ej1 #ade ,grevillea1 #ii ,gryllotalpa vulgaris1 #adf ,guillemard1 ,f4 ,h4 ,h41 #ij ,gmbel1 ,c4 ,w41 #aga1 #agf1 #ahh ,gymnostomum1 #bda ,gyroporella1 #agd1 #age1 #agf ,g4 bellerophontis1 #age ,hakea1 #ii ,half-relief fossils1 #gg ,halimeda1 #afd1 #ahe1 #bjb ,h4 gracilis1 #afd ,h4 ,saportae1 #afd ,haplographites cateniger1 #bag1 #bbj ,haploporella fasciculata1 #agg ,hartig1 ,r41 #bab ,harvey1 ,w4 ,h41 #afd ,hauck1 ,f41 #ahg1 #ahh ,heer1 ,o41 #f1 #dj1 #ea1 #fh1 #acb1 #aee1 #bgf1 #bhj1 #bhf1 #bij1 #cff ,heim1 ,a41 #bh ,helophyton1 #cdb ,henson1 #aah ,hepaticae1 #bcj-bcf ,herzer1 ,h41 #baa ,heterospory1 #cee1 #cef1 #ceg1 #djf ,hick1 ,t41 #cjd1 #cjf1 #ccj ,hicks1 ,h41 #aii1 #bjj1 #bjc ,hippurites1 #ccb1 #cga ,h4 gigantea1 #bfg ,h4 longifolia1 #cce ,holmes1 ,w4 ,h41 #gi ,homotaxis1 #ca ,hooker1 ,sir ,j41 #aj1 #af1 #fc1 #ij1 #aci1 #aea1 #bjc1 #bjd ,hookeria pennata1 #bca ,hostinella1 #bjj ,hughes1 ,t4 ,mc,kenny1 #ca ,humboldt1 ,a4 von1 #ad ,hutton1 ,w41 #hg ,huttonia1 #cfj1 #cfc ,huxley1 ,t4 ,h41 #ca ,hydatica1 #cdd ,hydrozoa1 #ahg1 #aij ,hyella1 #abg ,hyphochytrium infestans1 #bag ,ice-,age1 #ag1 #ec ,igneous rocks1 #bf1 #bg1 #ce ,incrustation1 #gi ,incrusting springs1 #fh ,india1 #hd1 #bhg-bhi1 #bib-bid1 #daa ,infranodal canals1 #bhe1 #cbd1 #cbg1 #cge ,inversion of strata1 #bi1 #cj ,italy1 #bhf1 #bhg1 #bia ,james1 ,j4 ,f41 #baj ,jungermannia1 #bcj1 #bcf ,jurassic system1 #dh-ej1 #ee1 #bbf1 #beg1 #bfi1 #bhb1 #bhc1 #bij1 #bia ,kaulfussia sculifolia1 #ig1 #ih ,keeling ,island1 #fe ,keeping1 ,w41 #adg ,kellaways rock1 #di ,kent1 ,s41 #ahd ,kerguelen ,land1 #af ,kerosene shale1 #agi-ahb ,keuper series1 #dg1 #dh1 #acj ,kickx1 ,j4 ,j41 #daa ,kidston1 ,r41 #dd1 #hb1 #adh1 #bfc1 #bfd1 #ccd1 #cgd1 #cge1 #che1 #chf1 #djf1 #djh1 #dji ,kieselguhr1 #aej ,kiltorkan beds1 #ci ,kimeridge clay1 #di1 #gh1 #aeh1 #aei ,kjellman1 ,f4 ,r41 #ahg ,koechlin-,schlumberger1 ,j41 #bfi ,kolguev ,island1 #baa ,klliker1 ,a41 #abg ,knig1 ,c41 #bfi ,knorria1 #aja1 #ajb1 #cff ,knowlton1 ,f4 ,h41 #h1 #bbe ,krakatoa1 #eh1 #aca ,kuntze1 ,o41 #ib ,laggan ,bay1 ,arran1 #hh ,lake1 ,p41 #bjj ,lamarck1 de1 #afa1 #age ,laminaria1 #adj1 #ada1 #aid1 #bjb ,lamouroux1 ,j41 #afa ,lapworth1 ,c41 #cg1 #adg ,laurentian rocks1 #cf ,lavas1 ,tertiary1 #eh ,leasowe1 #eh1 #ei ,leckenby1 ,j41 #bcc1 #bcd ,lehmann1 #ccf ,leithakalk1 #afi1 #ahg ,leocarpus1 #bjf ,lepidodendron1 #aj1 #eg1 #gb1 #ge1 #ha1 #hb1 #hi1 #aja1 #ajg1 #baf1 #bag1 #bah1 #bcg ,l4 ,veltheimianum1 #aja ,lepidostrobus1 #c ,leptothrix1 #abf ,lesquereux1 ,l41 #f1 #baj1 #bdj ,lessonia1 #adj1 #ada1 #aia1 #aic1 #bjb ,lettenkohle1 #dh1 #bfh ,lhwyd1 ,e41 #d1 #aab1 #cda ,lias1 #dh1 #di1 #fa1 #abj1 #aed1 #bbi1 #bdj1 #bgh ,limestone1 #be ,limulus1 #ade ,lindley1 ,t41 #ii1 #aje ,lindley1 ,t4 and ,hutton1 ,w41 #aj1 #bfg1 #bgf1 #bih1 #ccj1 #ccb1 #cdc1 #cff1 #cfi1 #cga1 #cge ,linnaeus1 #aac1 #bbe ,lithophyllum1 #ahc-ahg ,lithothamnion1 #ahc-ahi ,l4 crassum1 #ahe ,l4 fasciculatum1 #ahe ,l4 mamillosum1 #aee1 #ahh ,l4 suganum1 #ahf1 #ahh ,lithoxylon1 #aab1 #chf ,llandeilo flags1 #cg ,london clay1 #aec ,lough ,neagh1 #hj ,ludlow rocks1 #ch1 #bjc ,ludwig1 ,r41 #bab1 #bda ,lulworth ,cove1 #ef ,lunularia1 #bca ,lycopodiaceae1 #cij1 #dab1 #dac ,lycopodites1 #bcb1 #bcg ,l4 ,meeki1 #bdj ,lycopodium phlegmaria1 #bcg ,lyell1 ,sir ,c41 #eb1 #fj1 #fd1 #fe1 #gd1 #bbg1 #cbd ,lyginodendron1 #ai1 #bj1 #hh1 #ajc1 #bba ,lyme ,regis1 #fa ,mc,clelland1 #dab ,mc,coy1 ,f41 #bhd1 #bhh ,mc,murtrie1 ,j41 #cce ,macrocystis1 #aia1 #aid ,macrostachya1 #cej1 #cfj1 #cfb1 #cfc1 #cfd1 #cga1 #cha ,magnesian limestone1 #df ,mahr1 #daj ,mantell1 ,g41 #fb1 #ade ,marattiaceae1 #ih ,marchantia1 #bcj-bce ,m4 oolithus1 #bcb ,marchantiales1 #bcc-bcf ,marchantites1 #bcc-bcf ,m4 erectus1 #bcc ,m4 ,sezannensis1 #bce ,m4 ,zeilleri1 #bcd ,marcou1 ,j41 #df ,marsh1 ,o4 ,c41 #gi ,marsilia1 #cdb1 #cij ,martin1 ,w41 #big ,massalongo1 ,e4 ,g41 #f ,medusa1 #add ,meek1 ,f4 ,b41 #bce ,melobesia1 #ahd ,melobesieae1 #ahd ,memecylon1 #bad ,meschinelli1 #baj ,mesomycetes1 #bjh1 #baa ,metamorphism1 #cj ,michelin1 ,h41 #afc1 #afg ,micrococci1 #ach ,micrococcus1 #ace1 #acf ,m4 ,guignardi1 #acf ,m4 ,zeilleri1 #acd ,migula1 ,w41 #bbb ,millstone grit1 #dj1 #db1 #dc1 #cgf ,miocene rocks1 #eb1 #ahg1 #bda ,mississippi1 rafts1 #fd1 #fe ,mniaceae1 #bci ,mbius1 ,k4 ,a41 #aff1 #afg ,monocotyledons1 #ii1 #bdj1 #bgc1 #bia1 #cff ,mougeot1 ,a41 #cjj ,mountain limestone1 #dj1 #dc ,mucor1 #bac1 #bba ,m4 combrensis1 #bac ,mull1 leaf-beds in1 #eh ,munier-,chalmas1 ,e41 #afa1 #afc1 #afg1 #afh1 #aga1 #agb1 #agf ,murchison1 ,sir ,r41 #cg1 #ch1 #db ,murray1 ,g41 #aai-aba1 #abe1 #aeh1 #aei1 #agj1 #bjd1 #bdj ,murray1 ,j41 #aah1 #abj ,murray1 ,dr1 #hg ,muschelkalk series1 #dg ,musci1 #bcf-bda ,muscites1 #bch1 #bci1 #bda ,m4 ferrugineus1 #bda ,m4 polytrichaceus1 #bci ,mycelium1 #bjg ,mycomycetes1 #bjh1 #baa ,myeloxylon1 #ai1 #hf ,myriophylloides ,williamsonis1 #cdb ,myriophyllum1 #cdd ,myxomycetes1 #bje1 #bjf1 #bbj ,m4 ,mangini1 #bje1 #bjf ,najadita1 #bdj ,nansen1 #aea ,nathorst1 ,a4 ,g41 #fj1 #gg1 #gh1 #add1 #ade1 #adh1 #bcb1 #cff ,navicula1 #aec ,nematophycus1 #aib-bjd ,n4 crassus1 #aih1 #bja1 #bjb ,n4 ,dechianus1 #bja ,n4 ,hicksi1 #aii1 #bja ,n4 laxus1 #bja ,n4 ,logani1 #aid-aig1 #aii1 #bja1 #bjb ,n4 ,ortoni1 #bjj1 #bja ,n4 ,storriei1 #aic1 #aih-bja ,n4 tenuis1 #bja ,nesea1 #afa ,neumayr1 ,m41 #di ,neu ,paka1 #cfi ,neuropteris ,scheuchzeri1 #de ,new ,south ,wales1 #agi1 #aha1 #ahb1 #bhh ,newberry1 ,j4 ,s41 #adf ,nicholson1 ,h4 ,a41 #cch ,nicholson1 ,h4 ,a4 and ,etheridge1 ,j41 #abc1 #abd1 #aij ,nicol1 ,w41 #h ,nipa fruticans1 #fc ,nitelle1 #bbb1 #bbc1 #bbe ,nodules1 calcareous1 #he1 #hf1 #ajh ,nomenclature1 #aaj-aae ,nostoc1 #abc1 #acb ,nostocaceae1 #abb1 #abc ,nuclei1 fossil1 #hg1 #hh1 #cca ,nullipores1 #aga1 #ahd1 #ahe ,odontocaulis ,keepingi1 #adg ,old ,red ,sandstone1 #ci1 #bjd ,oldhamia1 #adf ,o4 antiqua1 #ade ,o4 radiata1 #ade1 #adf ,olenellus1 #cg ,oligocene1 #eb1 #ahh1 #bji1 #baa1 #bcd ,olpidium1 #baf ,oncylogonatum carbonarium1 #bfi ,onychiopsis ,mantelli1 #aab ,onychium1 #aab ,oochytrium ,lepidodendri1 #baf1 #bag ,oolite1 #di1 #gb1 #bfi1 #bga1 #bgf1 #bhf ,oolitic structure1 #abc-abf ,ophioglossum1 #cij d',orbigny1 ,a4 ,d41 #age ,ordovician1 #cg1 #ch1 #ahi1 #cch ,oscillariaceae1 #abb ,osmunda1 #hg ,osmundites ,dowkeri1 #bab ,ostracoblabe1 #abi ,o4 implexa1 #abi ,ovulites1 #afa-afd1 #agc ,o4 elongata1 #afc ,o4 margaritula1 #afb1 #afc1 #agd ,oxford clay1 #di ,pachytheca1 #bjb-bjd ,palaeachyla1 #abg1 #abi ,palaeomyces1 #bba ,p4 gracilis1 #bah ,palaeoperone endophytica1 #bae ,palaeostachya1 #cej1 #ceg-cfj1 #cfb1 #cfd1 #cga1 #cha ,p4 arborescens1 #cfc1 #cfd ,p4 pedunculata1 #ceg1 #ceh1 #cfb1 #cfc ,p4 vera1 #ceh1 #cei1 #cfb ,paleohepatica ,rostafinski1 #bcd ,pandanus1 #ii ,paracalamostachys1 #cfa ,paris basin1 #afa1 #afg1 #aga1 #agf ,parkinson1 ,j41 #a1 #gh ,parsons1 ,j41 #d ,peat1 #bf1 #ge1 #bbh1 #bcf ,pellia1 #bcj1 #bca ,penarth1 #dh ,penhallow1 ,d4 ,p41 #aic1 #aid1 #aig1 #bja1 #bjb1 #baj ,penicillus1 #aei1 #afa1 #afc1 #afd1 #bjb ,p4 pyramidalis1 #afb ,peridiniaceae1 #aag ,peridiniales1 #aag1 #aah ,peridinium1 #aag1 #aah ,p4 divergens1 #aah ,p4 pyrophorum1 #aah ,permian system1 #de1 #dg1 #acj1 #ahb1 #bji1 #bef1 #bhb1 #bhc1 #bih1 #cjj1 #cia1 #djh1 #dac ,permo-,carboniferous1 #df1 #bac1 #bbb1 #bef1 #bhd1 #bhi1 #bib1 #bic ,peronosporites1 #bah ,p4 antiquarius1 #bad1 #bag1 #bai ,petrifaction1 #gi-ij1 #ib ,petrified wood1 #gi-ij ,petrifying springs1 #fh ,pettycur1 #hh1 #cij1 #cig ,petzholdt1 ,a41 #bih1 #bii ,phaeophyceae1 #aej1 #aia-bjb ,philippi1 ,r4 ,a41 #ahe ,phillips1 ,j41 #bge1 #bgf ,phloeoterma1 #bed ,phycodes1 #adi ,phycomycetes1 #bah ,phycopsis1 #aib ,phyllotheca1 #bed-bef1 #bgf1 #bgg1 #bha-bhi1 #bib1 #bic1 #ccg ,p4 australis1 #bhd1 #bhg-bhi ,p4 ,brongniarti1 #bhf1 #bhg ,p4 carnosa1 #bia ,p4 deliquescens1 #bhc ,p4 indica1 #bhd1 #bhg-bhi ,p4 ,rallii1 #bhc ,p4 sibirica1 #bij ,phymatoderma1 #abj1 #adf1 #aed ,phytolithus1 #big1 #cce1 #cgc ,p4 sulcatus1 #cgd ,pila1 #ahj-ahb ,p4 bibractensis1 #aha ,p4 scotica1 #aha ,pinnularia1 #cdd1 #cha ,pith-casts1 of ,calamites1 #cfe-chj ,plagiochila1 #bcb ,plankton1 #aag1 #aah1 #aeb ,plauenscher ,grund1 #bih ,pleurococcaceae1 #aha ,pliocene rocks1 #eb1 #ec ,plot1 ,r41 #d ,poacites1 #cff ,podocarpus cupressina1 #bca1 #bcb ,podostemaceae1 #bca ,pollen-grains1 #ahb ,polydonia frondosa1 #add ,polygonace1 #if ,polygonum equisetiforme1 #if1 #ig ,polyporus1 #bjh1 #baa1 #bab ,p4 vaporarius1 #bag1 #bba ,polytrichum1 #bcf1 #bci ,polytrypa1 #agb ,polyzoa1 #adb1 #bca ,portland1 ,dirt-beds1 #di1 #ef1 #eg ,pothocites1 #che ,p4 ,grantoni1 #chf ,potoni1 ,r41 #bji1 #bei1 #bhf1 #ccg1 #djc ,precambrian rocks1 #cf ,presl1 ,r41 #e ,priority1 rule of1 #aac ,protannularia1 #cch ,proteace1 #ih ,protonema1 #bcj ,prototaxites1 #aib1 #aic ,psilotum1 #dab ,pteridophyta1 #bdb-dad ,pteropods1 #aef ,puccinia1 #bac ,purbeck1 #di1 #ef1 #eg1 #bbg ,pyrula1 #aeh ,pyxidicula1 #aed ,quekett1 ,j41 #abg ,rachiopteris1 #hf ,radiolaria1 #db1 #aah ,radstock1 #cce1 #cge ,reboulia1 #bca ,reefs1 #ahd1 #ahe ,reid1 ,clement1 #fj ,reinsch1 #ajf ,reinschia1 #ahj-ahb ,renault1 ,b41 #ajh1 #acj1 #acd1 #acf1 #ach1 #agh1 #bjf1 #bac1 #baf1 #bag1 #bah1 #bba1 #bbb1 #cji1 #cbj1 #cbh1 #cci1 #cdj1 #cdb1 #cdh1 #cdi1 #cfb-cfd1 #cfi1 #cge1 #chd1 #cij1 #cib1 #cii1 #djf ,renault1 ,b4 and ,bertrand1 ,c4 ,e41 #ace1 #acg1 #agh1 #ahj1 #aha ,renault1 ,b4 and ,zeiller1 ,r41 #bdj1 #bff1 #cga ,restio tetraphylla1 #ie ,reuss1 ,a4 ,e41 #afi ,rhabdoliths1 #abj ,rhabdospheres1 #aah1 #aba ,rhacophyllum1 #adb ,rhaetic series1 #dh1 #aee1 #bgh1 #bgi ,rhizodendron oppoliense1 #hd ,rhizogonium1 #bci ,rhodophyceae1 #abg1 #ahc1 #aij ,richea dracophylla1 #ii ,richmond1 ,virginia1 #aeb ,rill-marks1 #add ,rivularia1 #abf ,rivulariaceae1 #abi ,rock-building1 #bc ,rodway1 ,j41 #fd ,roots1 ,calamites1 #cdb-cdi ,rosanoff1 #ahg ,rose1 ,c4 ,b41 #abg1 #abh ,rosellinia congregata1 #bji ,rosellinites1 #bji ,r4 ,beyschlagii1 #bji ,rosenvinge1 ,l4 ,k41 #ahg ,ross1 ,sir ,j41 #aci ,rothliegendes strata1 #df ,rothpletz1 ,a41 #abj1 #adg1 #adh1 #aed1 #afj1 #age1 #agg1 #aib1 #chg ,rotularia1 #cij ,r4 marsileaefolia1 #djg ,rotuma ,island1 #ahd ,royle1 ,j4 ,f41 #daa ,rubeola mineralis1 #cda ,rufford1 ,p41 #aad1 #bhj ,rules for nomenclature1 #aaa-aae ,russia1 #bhb ,saccamina1 #aea ,saccardo1 ,p4 ,a41 #baj ,st4 tienne1 #acg1 #cij1 #cii ,salt ,lake1 #abb1 #abc ,salvinia1 #cee1 #cij ,sandberger1 ,f41 #agc ,sanderson1 #h ,sandstone1 #bd ,saporta1 ,marquis de1 #f1 #ajf1 #aad1 #agf1 #bcd1 #bce ,saprolegnia1 #bae ,sardinia1 #agg ,sargassum1 #aia ,saxony1 #gi ,scale-insects1 #baj ,schenk1 ,a41 #i1 #bgi ,scheuchzer1 ,j4 ,t41 #d1 #bif1 #cch1 #chi ,schimper1 ,w4 ,p41 #i1 #bfi1 #bga1 #bgf1 #cbb1 #cea1 #cfb1 #chf1 #daa ,schimper and ,mougeot1 #bia1 #bic ,schizomycetes1 #aba1 #acb-ach ,schizoneura1 #bed-bef1 #bgf1 #bhd1 #bhe1 #bia-bid ,s4 gondwanensis1 #bib1 #bic ,s4 paradoxa1 #bib1 #bic ,schizophyceae1 #aba-acb ,schizophyta1 #aba-ach ,schizopteris dichotoma1 #bcb ,s4 trichomanoides1 #bcb ,schizothrix1 #abe ,schlotheim1 ,e4 ,f4 von1 #e1 #big1 #ccb1 #chi ,schlter1 ,c41 #agf ,schmalhausen1 ,j41 #bhb1 #bhc1 #bhf1 #bhi1 #bij ,schoenlein1 ,j4 ,l4 and ,schenk1 ,a41 #bfi ,schrter1 ,j41 #bjf ,schulze1 ,c4 ,f41 #bif ,schulze1 ,f41 #hg ,schtt1 ,f41 #aah1 #aai1 #aba1 #aed ,schweinfurth1 ,g41 #ib ,schwendener1 ,s41 #dad ,sclerotia1 #bjg ,sclerotites ,salisburiae1 #baj ,scott1 ,d4 ,h41 #cja1 #cij1 #dje1 #dab1 #dac ,sea sawdust1 #abb ,secondary thickening1 #cjj ,sections1 geological1 #bg-bi ,sedgwick1 ,a41 #cf1 #cg1 #db ,seeds1 fossil1 #ia ,selaginella1 #bca1 #bcb1 #bcg1 #cee ,s4 ,oregana1 #bca1 #bcb1 #bdj ,s4 rupestris1 #bcb ,selaginellites1 #bcb1 #bcf ,sequoia1 #af ,szanne1 #gj1 #bce ,shales1 #bd ,sharpe1 ,s41 #fi1 #bbg ,shell-boring organisms1 #ahc ,shells1 #bd ,sheppey fruits1 #d ,shrubsole1 ,w4 ,h4 and ,kitton1 ,f41 #aec ,siberia1 #bij ,sigillaria1 #c1 #f1 #aj1 #ge1 #ajh ,silurian system1 #ch1 #aga1 #agc1 #agf1 #bjd ,siphoneae1 #abe1 #aef1 #aeg-agg1 #aic ,siphonema1 #afj ,skiddaw slate1 #cch ,skye1 ,island of1 #aea ,smilax1 #ii ,smith1 ,william1 #dc1 #dh ,smith1 ,worthington1 #bag1 #bah ,solenhofen plants1 #gh ,solenopora1 #ahi1 #aij ,s4 compacta1 #ahi ,sollas1 ,w4 ,j41 #adf ,solms-,laubach1 ,graf zu1 #gg1 #ib1 #adi1 #aff-afh1 #age1 #agg1 #ahg1 #aic1 #aid1 #bjj1 #bjd1 #bgg1 #bhb1 #bhf1 #cfj1 #cfb1 #cii1 #dje ,solomon ,islands1 #fe ,sorby1 ,h4 ,c41 #abj ,spencer1 ,j41 #cdb ,sphaeriaceae1 #bji1 #bbj ,sphaerites1 #bji ,sphaerocodium1 #afj ,s4 ,bornemanni1 #afj1 #ahf ,sphaerospermum1 #hg ,sphagnales1 #bcf ,sphagnum1 #bcf1 #bda ,sphenophyllales1 #chi-dad ,sphenophyllites1 #cij ,s4 emarginatus1 #djg ,sphenophyllostachys1 #djj1 #djb ,s4 ,dawsoni1 #djb1 #djc1 #dje ,s4 ,rmeri1 #dje1 #dac ,sphenophyllum1 #ajj1 #cej1 #chg-dad ,s4 antiquum1 #dac ,s4 cuneifolium1 #dja1 #djb1 #dje1 #djh1 #dac ,s4 emarginatum1 #cia1 #djg1 #djh ,s4 furcatum1 #chf ,s4 insigne1 #cid1 #cif1 #cig1 #djj1 #dac ,s4 myriophyllum1 #dji ,s4 oblongifolium1 #dac ,s4 osnabrugense1 #djg ,s4 plurifoliatum1 #cid1 #cif-cih1 #djj ,s4 speciosum1 #daa ,s4 tenerrimum1 #dji1 #dac ,s4 ,thoni1 #cia1 #daj1 #dac ,s4 trichomatosum1 #cih1 #djh1 #dji ,s4 truncatum1 #djg ,sphenopteris1 #gg1 #aab ,s4 ,mantelli1 #aab ,sphenothallus angustifolia1 #adh ,spiridens1 #bcg ,s4 longifolius1 #bcg ,spirophyton1 #add ,sprengel1 ,a41 #g ,sprudelstein1 #abc ,stachannularia1 #cdj1 #cfa ,starch-grains1 in fossil cells1 #bac ,stefani1 ,k4 de1 #aee1 #aef ,steinhauer1 ,h41 #e1 #big1 #cgc ,stenopora crinita1 #bae ,stenzel1 ,g41 #i1 #bih ,stephanopyxis1 #aed ,sternberg1 ,graf ,c4 von1 #e1 #ajd1 #beg1 #big1 #ccb1 #ccf1 #cfc1 #cga1 #chi ,sternbergia1 #ajd ,sterzel1 ,j4 ,t41 #cda1 #cgh1 #djh ,stigmaria and ,stigmarian appendages1 #c1 #aj1 #eg1 #ga1 #gb1 #gc1 #ajf1 #aaa1 #abc1 #bah1 #cje1 #caa1 #cdh1 #djd ,stigmatocanna ,volkmanniana1 #chf ,stokes1 ,c41 #hj ,stolley1 ,e41 #agb ,stoneworts1 #bbb-bbh ,storrie1 ,j41 #aih1 #bjc1 #bjd ,strata1 table of1 #ca1 #cb1 #cc ,stratigraphical ,geology1 #bf ,strickland1 ,h4 ,e41 #aaa1 #bjc ,stromatopora compacta1 #ahi ,stur1 ,d41 #caj1 #cdc1 #cfi1 #cgj1 #cge1 #cgf1 #cgh1 #chd1 #che1 #chf1 #chg1 #dji ,stylocalamites1 #cfg1 #cgd-cgf ,submerged forests1 #ei1 #fj ,suckow1 ,g4 ,a41 #bif1 #big1 #cjb ,surface-soils1 #ee-fj ,swanage1 #bbg ,sycidium1 #agc ,s4 melo1 #aee1 #agc ,synedra1 #aec ,tchikatcheff1 ,p4 de1 #bhc ,teleutospora ,milloti1 #bac ,tenison-,woods1 ,j4 ,e41 #bgi1 #bia ,teredo1 #fa1 #fb ,tertiary ,period1 #ea-ec ,thallophyta1 #aaf-bbh ,thiselton-,dyer1 ,w4 ,t41 #hg ,thomas1 ,k41 #ga van ,tieghem1 #acf ,tmesipteris1 #cij ,torbanehill1 #agi1 #ahb ,torbanite1 #agh1 #agi ,toula paper-coal1 #fh1 #acc ,trametes radiciperda1 #bae ,transition series1 #dj1 #dd1 #dac ,travertine1 #fi1 #gj1 #bcd1 #bce ,treub1 ,m41 #aca ,triassic system1 #dg1 #dh1 #gg1 #gh1 #hj1 #adf1 #aee1 #afj1 #aga1 #agd1 #age1 #bef1 #bfg1 #bfh1 #bib-bid ,trichomanes ,goebelianum1 #bdb ,trigonocarpon1 #ia ,triploporella1 #agg ,tristichia hypnoides1 #bca1 #bcb ,trizygia1 #daa1 #dab ,t4 speciosa1 #daa ,tuedian series1 #dc ,tulip tree1 #af ,turner1 ,d41 #aia ,tylodendron1 #ajd ,udotea1 #aga1 #ahe1 #bjb ,unconformity1 #bg ,underclay1 #dc ,unger1 ,f41 #ahg1 #bih1 #bii1 #cja ,uteria1 #agg ,vaillant1 ,s41 #bbe ,vascular ,cryptogams1 #bdb-dad ,vaucheria1 #aeg1 #agh ,venation1 #ii ,vermiporella1 #agb1 #agf ,vexillum1 #adi ,vinci1 ,leonardo da1 #b ,vogelsang1 ,h41 #acg ,volcanic rocks1 #cd1 #ea1 #hh1 #hi1 #ij ,volkmann1 ,g4 ,a41 #bif ,volkmannia1 #cej1 #cfj1 #cfa1 #cfb ,v4 ,binneyi1 #cea ,v4 ,dawsoni1 #dja ,v4 ,ludwigi1 #cea ,wallace1 ,a4 ,r41 #bde ,ward1 ,l41 #a ,wealden1 #ej1 #ee1 #aab1 #aad1 #bcd1 #beg1 #bgi1 #bhj ,weed1 ,w4 ,h41 #abf ,weiss1 ,c4 ,e41 #bij1 #cdc1 #cdd1 #cea1 #ceg1 #ceh1 #cfj-cfd1 #cfg1 #cfi1 #cgj1 #cga1 #cge1 #cgg1 #chh1 #dja1 #djh ,wenlock series1 #ch1 #abd1 #bjj1 #bjc ,wethered1 ,e41 #abd ,willdenow1 ,k4 ,l41 #bca ,wille1 ,n41 #agj ,williamson1 ,w4 ,c41 #i1 #aj1 #ga1 #id1 #ajj1 #ajc1 #acb1 #aed1 #bah1 #bbj1 #bca1 #bgc1 #bgf1 #cja1 #cjd1 #cae1 #cbb1 #cbd-cbf1 #cdb1 #cdf1 #cee1 #ceh1 #cij1 #cib1 #cig1 #dja1 #djc ,williamson1 ,w4 ,c4 and ,scott1 ,d4 ,h41 #hh1 #cjg1 #cab1 #cai1 #cbj1 #cdb1 #cdf1 #cdi1 #cee1 #ceh1 #cij1 #cib1 #cif1 #cig1 #dje1 #djf ,witham1 ,h41 #g1 #h ,withamia1 #aae ,wood-boring insects1 #ajg ,woodward1 ,j41 #c1 #aj1 #cd1 #ga1 #bif ,woronina1 #baf ,wnsch1 #hi ,yellowstone ,park1 #gi1 #ib1 #abf1 #aej ,yoredale rocks1 #dj1 #dc ,yorkshire coast1 #ee ,young1 ,g4 and ,bird1 ,j41 #bfi ,zechstein series1 #df ,zeiller1 ,r41 #gf1 #ajj1 #acc1 #adf1 #bcb1 #bfa1 #bfd1 #bfe1 #bhb1 #bhc1 #bhi1 #cfg1 #cge1 #cgh1 #cij1 #dja1 #djc1 #dje1 #djf1 #djh1 #dji1 #daj1 #daa ,zigno1 ,a4 de1 #f1 #bga1 #bgf1 #bhg ,zonatrichia calcivora1 #acj ,zonatrichites1 #abi1 #acj ,zygosporites1 #bad1 #bbj1 #bba ,,cambridge3 ,,printed ,,by ,j4 ,,and ,c4 ,f4 ,,clay1 ,,at ,,the ,,university ,,press4 ,,footnotes3 #a ,ward 7#hd74 #b ,gppert 7#cf74 #c ,parkinson 7#aa71 vol4 ,i4 #d ,for an account of the early views on fossils1 v4 ,lyell 7#fg71 ,vol4 ,i4 ,vide also ,leonardo da ,vinci 7#hc74 #e ,woodward1 ,j4 7#afie71 ,preface4 #f ,woodward1 ,j4 7#agbh71 p4 #ei4 #g ,mendes da ,costa 7#ageh71 p4 #bcb4 #h ,scheuchzer 7#agbc71 p4 #g1 ,pl4 ,i4 fig4 #a4 #i ,parsons 7#ageg71 p4 #djb4 #aj ,plot 7#agje71 p4 #abe1 ,pl4 ,,vi4 fig4 #b4 #aa ,ibid4 ,pl4 ,,vi4 fig4 #b4 #ab ,lhwyd 7#agfj74 #ac ,artis 7#be74 #ad ,steinhauer 7#ah74 #ae ,schlotheim 7#jd74 #af ,sternberg 7#bj74 #ag ,brongniart 7#bh7 7#bh7 7#di74 #ah ,brongniart 7#ci74 #ai ,heer 7#ee7 7#fh7 7#gf74 #bj ,lesquereux 7#ff7 7#gj7 7#hj7 etc4 #ba ,zigno 7#ef74 #bb ,massalongo 7#ea74 #bc ,saporta 7#gb7 7#gc74 #bd ,ettingshausen 7#gi74 ,also numerous papers on fossil plants from ,austria and other countries4 #be ,sprengel 7#bh74 #bf ,witham 7#cc74 #bg ibid41 p4 #c4 #bh ,witham 7#cc71 p4 #e4 #bi ,nicol 7#cd74 ,see note by ,prof4 ,jameson on p4 #aeg of the paper quoted1 to the effect that he has long known of this method of preparing sections4 #cj ,limpricht 7#ij7 in ,rabenhorst1 vol4 ,,iv4 p4 #gc4 #ca ,knowlton 7#hi74 #cb ,corda 7#de74 #cc ,binney 7#fh71 ,introductory remarks4 #cd ,williamson 7#ga71 etc4 #ce ,solms-,laubach 7#ie71 p4 #ddb4 #cf ,lindley and ,hutton 7#ca74 #cg ,woodward 7#agbi71 ,pt4 ii4 p4 #ajf4 #ch ,humboldt 7#dh71 vol4 ,i4 p4 #bgd4 #ci ,vide ,hooker1 ,j4 ,d4 7#ha71 for references to other writers on this subject2 also ,darwin 7#hb71 ch4 ,,xii4 #dj ,darwin 7#hg71 vol4 ,,iii4 p4 #bdg4 #da ,brongniart 7#di71 p4 #id4 #db ,grand',eury 7#gg71 ,potoni 7#if71 ,kidston 7#id71 c4 #dc ,ward 7#ib71 ,knowlton 7#id71 ,grand',eury 7#ij71 p4 #aee4 #dd ,old ,persian writer1 quoted by ,e4 ,g4 ,browne in ,a ,year among the ,persians1 p4 #bbj1 ,london1 #ahic4 #de ,w4 ,r4 ,w4 ,stephens1 ,life of ,freeman1 p4 #acb1 ,london1 #ahie4 #df ,rothpletz 7#id74 #dg ,heim 7#gh74 #dh ,geikie 7#ic71 p4 #gjf4 #di ,hughes 7#gi71 p4 #bdh4 #ej ,whitney and ,wadsworth 7#hd74 #ea ,murchison 7#gb71 p4 #e4 #eb ,kayser and ,lake 7#ie71 p4 #hh4 #ec ,kidston 7#id74 #ed ,geikie 7#ic71 p4 #hbe4 #ee ,woodward1 ,h4 ,b4 7#hg71 p4 #aig4 #ef ,hinde and ,fox 7#ie71 p4 #ffb4 #eg ,kidston 7#id74 #eh ,vide ,zeiller 7#ib7 for a list of species of ,coal-,measure plants found in the pieces of shale included in the core brought up by the borer4 #ei ,jukes-,browne 7#hf71 p4 #beb4 #fj ,kayser and ,lake 7#ie71 p4 #aif4 #fa ,neumayr 7#hc74 #fb ,woodward1 ,h4 ,b4 7#hg71 p4 #bee4 #fc ,kayser and ,lake 7#ie71 p4 #cbf4 #fd ,huxley 7#ic71 p4 #bg4 #fe ,discussed at greater length in vol4 ,,ii4 #ff ,woodward1 ,h4 ,b4 7#ie71 ,figs4 #abd and #acc from photographs by ,mr ,strahan4 #fg ,buckland 7#cg7 ,pl4 ,,lvii4 #fh ,young1 ,glen1 and ,kidston 7#hh74 #fi ,gardner 7#hg71 p4 #bgi4 #gj ,treub 7#hh74 #ga ,morton 7#ia71 p4 #bbh4 #gb ,lyell 7#de71 vol4 ,i4 p4 #ahj4 #gc ,mantell 7#dd71 vol4 ,i4 p4 #afh4 #gd ,forbes1 ,h4 ,o4 7#he71 p4 #bed4 #ge ,hooker1 ,j4 ,d4 7#ia71 p4 #dgg4 #gf ,hooker1 ,j4 ,d4 7#ia71 p4 #a4 ,there are several good specimens of the black pyritised nipadite fruits in the ,british ,museum and other collections4 #gg ,rodway 7#ie71 p4 #ajf4 #gh ,bates 7#fc71 p4 #aci4 #gi ,bates 7#fc71 p4 #bci4 #hj ,lyell 7#fg7 vol4 ,,ii4 p4 #cfa4 #ha ,lyell 7#fg7 vol4 ,i4 p4 #dde4 #hb ,darwin 7#ij7 p4 #ddc4 #hc ,challenger 7#he71 ,narrative1 vol4 ,i4 ,pt4 ii4 p4 #fgi4 #hd ,bates 7#fc7 p4 #chi4 #he ,challenger 7#he71 ,narrative1 vol4 ,i4 p4 #dei4 #hf ,zeiller 7#hb7 and ,renault 7#ie74 #hg ,heer 7#gf74 #hh ,schimper and ,mougeot 7#dd74 #hi ,sharpe1 ,s4 7#fh7 p4 #efc4 #ij ,there are still more perfect casts from ,szanne in ,prof4 ,munier-,chalmas' ,geological collection in the ,sorbonne4 ,the best examples have not yet been figured4 #ia ,saporta 7#fh74 #ib ,darwin 7#ij7 p4 #dcb4 #ic ,for figures of fossil plants in amber1 vide ,gppert and ,berendt 7#de71 ,conwentz 7#ij71 ,conwentz 7#if7 c4 #id ,thomas 7#dh74 #ie ,adamson 7#hh74 #if ,williamson 7#hg7 ,pl4 ,,xv4 p4 #de4 ,a very fine specimen1 similar to that in the ,manchester ,museum1 has recently been added to the ,school of ,mines ,museum in ,berlin2 ,potoni 7#ij74 #ig ,the ,british ,museum collection contains a specimen of ,stigmaria preserved in the same manner as the example shown in fig4 #ab4 #ih ,lyell 7#de7 vol4 ,i4 p4 #fj4 #ii ,lyell 7#de7 vol4 ,i4 p4 #adg4 #ajj ,warming 7#if7 p4 #agj4 #aja ,bornemann 7#ef71 ,schenk 7#fg71 ,zeiller 7#hb74 #ajb ,solms-,laubach 7#ie74 #ajc ,nathorst 7#hf7 p4 #i4 ,see also ,delgado 7#hf74 #ajd ,parkinson 7#aa7 vol4 ,i4 p4 #dca4 #aje ,the ,british ,museum collection contains many good examples of the ,solenhofen plants4 #ajf ,there is a splendid silicified tree stem from ,tasmania of ,tertiary age several feet in height in the ,national ,museum4 #ajg ,darwin 7#ij7 p4 #cag4 #ajh ,holmes 7#hj7 p4 #abf1 fig4 #a4 #aji ,marsh 7#ga74 #aaj ,conwentz 7#gh74 #aaa ,a large piece from one of these ,south ,african trees is in the ,fossil-plant ,gallery of the ,british ,museum4 #aab ,barton 7#agea7 p4 #eh4 #aac ,gardner 7#hd7 p4 #cad4 #aad ,stokes 7#dj7 p4 #bjg4 #aae ,witham 7#ha71 ,christison 7#gf74 #aaf ,cole 7#id71 figs4 #a and #c4 #aag ,harker 7#ie7 p4 #bcc1 fig4 #ef4 #aah ,i am indebted to ,dr ,renault of ,paris for showing to me several preparations illustrating this method of petrifaction4 #aai ,cash and ,hick 7#gh74 #abj ,stur 7#he74 #aba ,thiselton-,dyer 7#gb7 ,pl4 ,,vi4 #abb ,carruthers 7#gj74 #abc ,schultze 7#ee74 #abd ,i am indebted to ,prof4 ,lebour of the ,durham ,college of ,science for the loan of this letter4 #abe ,seward 7#ig74 #abf ,williamson and ,scott 7#if7 ,pl4 ,,xxiv4 fig4 #af4 #abg ,bryce 7#gb7 p4 #abf1 fig4 #bc4 #abh ,an erroneous interpretation of the ,arran stems is given in ,lyell's ,elements of ,geology3 ,lyell 7#gh7 p4 #edg4 #abi ,guillemard 7#hf7 p4 #cbb4 #acj ,heer 7#ee74 #aca ,gppert 7#cf71 etc4 #acb ,hirschwald 7#gc74 #acc ,kuntze 7#hj7 p4 #h4 #acd ,schweinfurth 7#hb74 #ace ,solms-,laubach 7#ia71 p4 #bi4 #acf ,gppert 7#eg74 ,some of the large silicified trees mentioned by ,gppert may be seen in the ,breslau ,botanic gardens4 #acg ,an example referred to by ,carruthers 7#ga7 p4 #ddd4 #ach ,williamson 7#ga7 p4 #ejg4 #aci ,dealt with more fully in vol4 ,,ii4 #adj ,bentham 7#gj74 #ada ,see also ,bunbury 7#hc7 p4 #cji4 #adb ,seward 7#if7 p4 #bjh4 #adc ,darwin 7#ij7 p4 #daf4 #add ,solms-,laubach 7#ia7 p4 #i4 #ade ,balfour 7#gb7 p4 #e4 #adf ,grand',eury 7#gg7 ,pt4 i41 p4 #c4 #adg #a ,renault and ,zeiller 7#hh7 ,pl4 ,,lx4 fig4 #a4 #adh ,williamson 7#gc7 p4 #cic1 ,pl4 ,,xxvii4 ,described in detail in vol4 ,,ii4 ,see also ,solms-,laubach 7#ia7 p4 #g1 fig4 #a4 #adi ,a good example is figured by ,newberry 7#hh7 ,pl4 ,,xxv4 as a decorticated coniferous stem of ,triassic age4 #aej ,potoni 7#hg74 #aea ,lindley and ,hutton 7#ca7 vol4 ,,iii4 p4 #d4 ,see also ,schenk 7#hh7 p4 #bjb4 #aeb ,saporta 7#gi7 7#gg74 ,eopteris is included among the ferns in ,schimper and ,schenk's volume of ,zittel's ,handbuch der ,palaeontologie 7p4 #aae71 and in some other modern works4 #aec ,reinsch 7#ha74 #aed ,williamson has drawn attention to the occurrence of such borings and coprolites in ,coal-,measure plant tissues4 ,e4g4 ,williamson 7#hj7 ,pl4 #bj1 figs4 #fe and #ff4 #aee ,renault 7#if7 p4 #dcg4 #aef ,slide ,no4 #aibc in the ,williamson collection4 #aeg ,crpin 7#ha74 #aeh ,rules for ,zoological ,nomenclature1 drawn up by the late ,h4 ,e4 ,strickland1 ,m4,a41 ,f4,r4,s41 ,london1 #ahgh4 #aei ,lhwyd 7#afii74 #afj ,knowlton 7#if7 p4 #hb4 #afa ,thiselton-,dyer 7#ie7 p4 #hdf4 #afb ,saporta 7#ge7 p4 #aic4 #afc ,seward 7#ie7 p4 #agc4 #afd ,ward 7#if7 p4 #hgd4 #afe ,challenger 7#he7 p4 #icd4 #aff ,ehrenberg 7#cf7 p4 #aag1 ,pl4 ,i4 figs4 #a and #d1 and ,ehrenberg 7#ed7 ,pl4 ,,xxxvii4 fig4 vii4 #afg ,schtt 7#if7 p4 #bb4 #afh ,btschli 7#hc-hg7 p4 #ajbh4 #afi ,challenger ,reports 7#he7 p4 #ici4 #agj ,challenger ,reports 7#ia7 p4 #beg4 #aga ,hensen 7#ib71 ,schtt 7#ic7 p4 #dd4 #agb ,murray1 ,g41 and ,blackman1 ,v4 ,h4 7#ig74 #agc ,dixon and ,joly 7#ig74 #agd ,sorby 7#gi7 p4 #gh4 #age ,rothpletz 7#if71 p4 #iji1 ,pl4 ,,xxiii4 fig4 #d4 #agf ,challenger 7#he7 passim4 ,schtt 7#ic74 #agg ,phillips ,w4 7#ic74 #agh ,kippis 7#gh7 p4 #aae4 #agi ,darwin 7#ij7 p4 #ac4 #ahj ,rothpletz 7#ib74 #aha ,walther 7#hh74 #ahb ,cohn 7#fb74 #ahc ,murray1 ,g4 7#ie74 #ahd ,thiselton-,dyer 7#ia7 p4 #bbf4 #ahe ,nicholson and ,etheridge 7#hj7 p4 #bh1 ,pl4 ,,ix4 fig4 #bd4 #ahf ,wethered 7#ic7 p4 #bcg4 #ahg ,for figures of the sheaths of ,cyanophyceous algae1 see ,murray 7#ie71 ,pl4 ,,xix4 fig4 #e4 ,gomont 7#hh7 and 7#ib72 etc4 #ahh ,brown 7#id7 p4 #bjc4 #ahi ,for references to the papers of ,wethered and others1 see ,seward 7#id71 p4 #bd4 #aij ,e4 ,g4 ,bornemann 7#hg71 ,pl4 ,,ii4 #aia ,moseley1 ,h4 ,n4 7#ge71 p4 #cba4 #aib ,weed 7#hg-hh71 vide also ,tilden 7#ig74 #aic ,bornet and ,flahault 7#hi7 ,pl4 ,,xi4 #aid ,batters 7#ib74 #aie ,quekett 7#ed71 fig4 #gh4 #aif ,klliker 7#ei7 and 7#ei72 good figures in the latter paper4 #aig ,rose 7#ee71 ,pl4 ,i4 #aih ,for other references vide ,bornet and ,flahault 7#hi74 #aii ,duncan 7#gf7 and 7#gf74 #bjj ,similar borings are figured by ,klliker 7#ei71 ,pl4 ,,xvi4 #ad1 in a scale of ,beryx ornatus from the ,chalk4 #bja ,bornet and ,flahault 7#hi74 #bjb ,e4 ,g4 ,wedl 7#ei74 ,good figures are given in this paper4 #bjc ,bornemann 7#hf71 p4 #abf1 ,pls4 ,v4 and ,,vi4 #bjd ,renault 7#if7 p4 #ddf4 #bje ,treub 7#hh74 #bjf ,williamson 7#hh74 #bjg ,heer 7#ee7 vol4 ,i4 p4 #ba1 ,pl4 ,,iv4 fig4 #b4 #bjh de ,bary 7#hg7 p4 #i4 ,a good account of the ,schizomycetes has lately been written by ,migula in ,engler and ,prantl's ,pflanzenfamilien1 ,leipzig1 #ahif4 #bji #a #jjja millimetres4 #baj ,james 7#ih71 translation of a paper by ,m4 ,ferry in the ,revue ,mycologique1 #ahic4 #baa ,zeiller 7#hb74 #bab ,renault 7#ie71 7#if7 p4 #dgh1 7#if7 p4 #ajf4 7,several figures of the cuticles are given in these publications47 #bac ,renault 7#if7 p4 #dib4 #bad ,renault 7#ie71 7#if71 7#if74 #bae ,renault and ,bertrand 7#id74 ,see also ,renault 7#ie7 p4 #c1 7#if7 p4 #ddi1 ,pl4 ,,lxxxix4 7#if7 p4 #id1 and 7#if7 p4 #bhj1 fig4 #c4 #baf ,renault 7#ie7 p4 #ag1 fig4 #i1 7#if7 p4 #dfj1 fig4 #ajb1 and 7#if7 p4 #bib1 fig4 #aj4 #bag ,renault 7#if7 p4 #big1 fig4 #ad4 #bah ,van ,tieghem 7#gg74 #bai ,van ,tieghem 7#gi74 #bbj ,vogelsang 7#gd74 ,vide also ,rutley 7#ib74 #bba ,i am indebted to ,prof4 ,kanthack for calling my attention to an interesting account of ,bacilli in small stones found in gall-bladders2 a manner of occurrence comparable to that of the fossil forms in petrified tissues4 ,vide ,naunyn 7#if7 p4 #ea4 #bbb ,renault 7#if7 p4 #bgg4 #bbc ,hooker1 ,j4 ,d4 7#dd7 p4 #deg4 ,pls4 ,,clxvii4 ,,clxviii4 and ,,clxxi4 ,d4 #bbd ,an ,american writer has recently discussed the literature and history of ,fucoides2 he gives a list of #he species4 ,it is very doubtful if such work as this is worth the labour4 7,james #ic47 #bbe ,wille 7#ig7 p4 #acf1 also ,murray1 ,g4 7#ie7 p4 #aba4 #bbf ,linnarsson 7#fi7 ,pl4 ,,xi4 fig4 #c4 ,there are many good specimens of this fossil in the ,geological ,survey ,museum1 ,stockholm4 #bbg ,nathorst 7#ha71 and 7#if74 #bbh ,nathorst 7#ha7 p4 #ad4 #bbi ,mantell 7#cc7 p4 #aff4 ,vide also ,morris 7#ed7 p4 #f4 #bcj ,bateson 7#hh74 #bca ,nathorst 7#ha71 7#hf7 c4 ,dawson 7#hh7 p4 #bf et seq4 ,dawson 7#ij7 ,delgado 7#hf7 ,williamson 7#he7 ,hughes 7#hd7 ,zeiller 7#hd7 ,saporta 7#ha7 7#hb7 7#hd7 7#hf7 ,fuchs 7#ie7 ,rothpletz 7#if74 #bcb ,kinahan 7#eh74 #bcc ,sollas 7#hf74 #bcd ,barrois 7#hh74 ,references to other records of this genus may be found in ,barrois' paper4 #bce ,zeiller 7#hd74 ,phymatoderma is probably a horny sponge 7vide p4 #aed74 #bcf ,newberry 7#hh7 p4 #hb1 ,pl4 ,,xxi4 ,there are some large specimens of this supposed alga in the ,national ,museum1 ,washington2 they are undoubtedly of the nature of rill-marks4 #bcg ,vide ,williamson 7#he74 #bch ,dawson 7#ij7 p4 #fae4 #bci ,salter 7#gh7 p4 #ii4 #bdj ,lapworth 7#ha7 p4 #agf1 ,pl4 ,,vii4 fig4 #g4 #bda ,rothpletz 7#if74 #bdb ,a term applied to a certain facies of ,eocene and ,oligocene rocks in ,central ,europe4 #bdc ,hall 7#dg7 ,pl4 ,,lxviii4 #a and #b1 p4 #bfa4 #bdd ,nathorst 7#hc7 p4 #dec4 #bde ,seward 7#id7 p4 #d4 #bdf ,kidston 7#hc7 ,pl4 ,,xxxii4 fig4 #b4 ,specimens of this form may be seen in the ,british ,museum collection4 #bdg ,cf4 ,matthew1 ,g4 ,f4 7#hi74 ,hall called attention in #aheb to the prevalent habit of describing #8algae' from the older strata1 without any evidence for a vegetable origin4 7,hall #eb p4 #ah47 #bdh ,credner 7#hg7 p4 #dca4 #bdi ,saporta 7#hd7 p4 #de1 ,pl4 ,,vii4 #bej ,solms-,laubach 7#ia7 p4 #ea4 #bea ,a monograph on the ,diatomaceae has recently been written by ,schtt for ,engler and ,prantl's systematic work4 ,see also ,murray1 ,g4 7#ig7 and ,pfitzer 7#ga74 #beb ,darwin 7#ij7 p4 #e4 #bec ,weed 7#hg74 #bed ,wilson 7#hg74 #bee ,ehrenberg 7#ed74 #bef ,noll 7#ie7 p4 #bdh4 #beg ,hooker1 ,j4 ,d4 7#dd7 vol4 ,i4 p4 #ejc4 #beh ,murray1 ,j4 and ,renard 7#ia7 p4 #bjh4 #bei ,nansen1 ,daily ,chronicle1 ,nov4 #b1 #ahif4 #bfj ,schtt 7#ic7 p4 #aj4 #bfa ,ehrenberg 7#cf7 p4 #gg4 #bfb ,cayeux 7#ib71 7#ig74 #bfc ,shrubsole and ,kitton 7#ha74 #bfd ,i am indebted to ,mr ,murton ,holmes for specimens of these ,london ,clay ,diatoms4 #bfe ,rothpletz 7#if7 p4 #iaj1 fig4 #c1 ,pl4 ,,xxiii4 fig4 #bjc4 #bff ,schtt 7#if7 p4 #fb4 #bfg ,castracane 7#gf74 #bfh ,heer 7#gf7 p4 #ff1 ,pl4 ,,xxiii4 and 7#ec7 p4 #aag1 ,pl4 ,,vi4 #bfi ,stefani 7#hb7 p4 #ajc4 #bgj ,the ,chlorophyceae have recently been exhaustively dealt with by ,wille 7#ig7 in ,engler and ,prantl's ,pflanzenfamilien4 #bga ,vide p4 #adb4 #bgb ,murray ,g4 7#ie7 p4 #abc4 #bgc ,gppert 7#fj7 p4 #dci4 ,pl4 ,,xxxiv4 fig4 #h4 #bgd ,zeiller 7#hd74 #bge ,murray ,g4 7#ib7 p4 #aa2 also 7#ie7 p4 #abg4 #bgf ,damon 7#hh7 ,pl4 ,,xix4 fig4 #ab4 #bgg ,vide also ,rothpletz 7#if7 p4 #hid4 #bgh ,ellis 7#agee7 ,pl4 ,,xxxiii4 p4 #hf4 #bgi ,fuchs 7#if7 ,pl4 ,,viii4 fig4 #c4 #bhj ,murray ,g4 7#ie7 ,pl4 ,,iii4 figs4 #a and #b4 #bha ,rothpletz 7#ij71 and 7#ia7 ,pls4 ,,xv4 and ,,xvi4 #bhb ,bornemann 7#hg7 p4 #ag1 ,pl4 ,,ii4 pp4 #a-d4 #bhc ,lamouroux 7#ba7 ,pl4 ,,xxv4 fig4 #e1 p4 #bc4 #bhd ,munier-,chalmas 7#gi74 #bhe ,for references to genera of calcareous algae previously referred to ,foraminifera1 vide ,sherborn 7#ic74 #bhf ,lamarck 7#af7 p4 #aic4 #bhg ,defrance 7#bf7 ,pl4 ,,xlviii4 fig4 #b1 and ,pl4 ,l4 fig4 #f4 #bhh ,carpenter 7#fb7 p4 #agi1 ,pl4 ,,xii4 figs4 #i and #aj4 #bhi ,michelin 7#dj-dg7 ,pl4 ,,xlvi4 fig4 #bd4 #bij ,munier-,chalmas 7#gi74 #bia ,lamouroux 7#ba7 ,pl4 ,,xxv4 fig4 #f1 p4 #bc4 #bib ,harvey 7#eh7 ,vol4 ,i4 ,pl4 ,,xxii4 fig4 #c4 #bic ,fuchs 7#id74 #bid ,lamouroux gives a figure of ,acetabularia1 and includes this genus with several other algae in the animal kingdom 7,lamouroux #ba p4 #ai71 ,pl4 ,,lxix474 #bie ,solms-,laubach 7#ie74 #bif ,d',archiac 7#dc7 p4 #chf1 ,pl4 ,,xxv4 fig4 #h4 #big ,solms-,laubach loc4 cit4 p4 #cc1 ,pl4 ,,iii4 #bih ,d',archiac 7#dc7 p4 #chf1 ,pl4 ,,xxv4 fig4 #h4 #bii ,michelin 7#dj7 p4 #agf1 ,pl4 ,,xlvi4 fig4 #ad4 #cjj ,carpenter 7#fb7 p4 #acg1 ,pl4 ,,xi4 figs4 #bg-hb4 #cja ,solms-,laubach loc4 cit4 p4 #cb4 #cjb ,ibid4 p4 #cd1 ,pl4 ,,iii4 fig4 #ac4 #cjc ,andrussow 7#hg74 #cjd ,solms-,laubach 7#ie7 p4 #aa4 #cje ,carpenter 7#fb7 ,pl4 ,,xi4 fig4 #cb4 #cjf ,reuss 7#fa7 p4 #h1 figs4 #e-h4 #cjg ,ellis 7#agee7 ,pl4 ,,xxv4 ,c4 #cjh ,solms-,laubach 7#ia7 p4 #ch gives a detailed description with two figures of a recent species of ,cymopolia4 #cji ,murray ,g4 7#ie74 #caj ,wille 7#ig74 #caa ,munier-,chalmas 7#gg74 #cab ,cramer 7#hg7 7#ij74 #cac ,solms-,laubach 7#ia7 7#ic7 7#ie74 #cad ,church 7#ie74 #cae ,gmbel 7#ga74 #caf ,benecke 7#gf74 #cag ,defrance 7#bf7 p4 #dec4 #cah ,munier-,chalmas 7#gg7 p4 #hae4 #cai ,munier-,chalmas ibid4 #cbj ,defrance 7#bf7 ,pl4 ,,xlviii4 fig4 #a4 #cba ,stolley 7#ic74 #cbb ,deecke 7#hc74 #cbc ,benecke 7#gf7 ,pl4 ,,xxiii4 #cbd ,solms-,laubach 7#ia7 p4 #db4 #cbe ,rothpletz 7#id7 p4 #bd4 #cbf ,lamarck 7#af7 p4 #ahh4 #cbg ,carpenter 7#fb7 ,pl4 ,x4 #cbh ,gmbel 7#ga74 ,vide also ,solms-,laubach 7#ia7 p4 #ci4 #cbi ,stolley 7#ic74 #ccj ,schlter 7#gi74 #cca ,saporta 7#ia7 ,pl4 ,,xxxii4 c4 #ccb ,solms-,laubach 7#ic71 ,pl4 ,,ix4 figs4 #a1 #h4 #ccc ,cramer 7#ij74 #ccd ,rothpletz 7#ib7 p4 #bce4 #cce ,steinmann 7#hj74 #ccf ,solms-,laubach 7#ia71 p4 #dj4 fig4 #c4 ,vide also ,deecke 7#hc7 ,pl4 ,i4 fig4 #ab4 #ccg ,brongniart 7#bh7 p4 #baa4 #cch ,bornemann 7#ia7 p4 #dhe4 ,pls4 #db and #dc4 #cci ,seward 7#ie7 p4 #cfg4 #cdj ,report of the ,trial 7#fb74 #cda ,bertrand and ,renault 7#ib7 p4 #bi4 #cdb ,bertrand 7#ic71 ,bertrand and ,renault 7#ib7 7#id71 ,bertrand 7#if71 ,renault 7#if74 ,additional references may be found in these memoirs4 #cdc ,batters 7#ib74 ,vide also ,schmitz 7#ig7 p4 #cae4 #cdd ,hauck 7#he7 in ,rabenhorst's ,kryptogamen ,flora1 vol4 ,,ii4 #cde ,kent 7#ic7 p4 #adj4 #cdf ,agassiz 7#hh7 vol4 ,i4 p4 #hb4 #cdg ,walther 7#he74 #cdh ,ibid4 7#hh7 p4 #dgh4 #cdi ,philippi 7#cg7 p4 #chg4 #cej ,rosanoff7#ff7 ,pl4 ,,vi4 fig4 #aj4 #cea ,rothpletz 7#ia7 ,pl4 ,,xvii4 fig4 #d4 #ceb ,frh 7#ij7 fig4 #ab4 #cec ,kjellman 7#hc74 #ced ,holmes and ,batters 7#ij7 p4 #ajb4 #cee ,hauck 7#he74 ,rosanoff 7#ff74 ,rosenvinge 7#ic7 p4 #ggi4 ,kjellman 7#hc7 p4 #hh4 ,solms-,laubach 7#ha74 #cef ,unger 7#eh74 #ceg ,a microscopic section of the ,vienna ,leithakalk is figured in ,nicholson and ,lydekker's ,manual of ,palontology 7#hi7 vol4 ,,ii4 p4 #adig4 #ceh ,gmbel 7#ga7 ,pl4 ,,ii4 fig4 #g1 p4 #da4 #cei ,hauck 7#he7 p4 #bgb4 #cfj ,rothpletz 7#ia7 ,pl4 ,,xvii4 fig4 #d4 #cfa ,vide ,walther 7#hh7 p4 #dii2 also ,jukes-,browne and ,harrison 7#ia7 passim4 ,i am indebted to ,mr ,g4 ,f4 ,franks1 who has studied the ,barbadian reefs1 for the opportunity of examining sections of ,west-,indian coral-rock4 #cfb ,brown ,a4 7#id74 #cfc ,brown ,a4 7#id7 p4 #adg4 #cfd ibid4 p4 #bjj4 #cfe e4g4 ,saporta 7#hb7 p4 #ab4 #cff ,turner 7#aa7 vol4 ,,ii4 p4 #ea4 #cfg ,rothpletz 7#if74 #cfh ,penhallow 7#if7 p4 #de4 #cfi ,dawson 7#ei74 #cgj ,vide #8,academy' #ahgj1 p4 #af4 #cga ,carruthers 7#gb74 #cgb ,penhallow 7#hi74 #cgc ,barber 7#ib74 #cgd ,solms-,laubach 7#ie74 #cge ,penhallow 7#if74 #cgf loc4 cit4 p4 #hc4 #cgg ,dawson 7#ei71 also 7#ga7 p4 #ag4 #cgh ,penhallow 7#hi7 and 7#if7 p4 #df4 #cgi ,barber 7#ib7 p4 #ccf4 #chj ,penhallow 7#hi7 and 7#ic74 #cha ,dawson 7#ha7 p4 #cjb4 #chb ,barber 7#ib74 #chc ,hicks 7#ha7 p4 #dij4 #chd ,lake 7#ie7 p4 #bb4 #che ,solms-,laubach 7#ie74 #chf ,a similar method of fossilisation has been noted by ,rothpletz in the case of the ,lower ,devonian alga ,hostinella4 ,rothpletz 7#if7 p4 #hif4 #chg ,penhallow 7#if7 p4 #dg4 #chh ,carruthers 7#gb7 p4 #afb regards this species as identical with ,n4 ,logani4 #chi ,seward 7#ie74 #cij ,strickland and ,hooker 7#ec74 #cia ,hicks 7#ha7 p4 #dhd4 #cib ,dawson 7#hb7 p4 #ajd4 #cic ,barber 7#hi7 and 7#ij74 #cid ,murray ,g4 7#ie74 #cie ,hooker ,j4 ,d4 7#hi74 #cif loc4 cit4 #cig ,solms-,laubach 7#ie7 p4 #ha4 #cih ,seward 7#id7 p4 #d4 #cii ,an excellent monograph on the ,mycetozoa has lately been issued by the ,trustees of the ,british ,museum under the authorship of ,mr ,a4 ,lister 7#id74 ,vide also ,schrter 7#hi7 in ,engler and ,prantl's ,natrlichen ,pflanzenfamilien4 #djj ,renault 7#if7 p4 #dbb1 figs4 #ge and #gf4 #dja ,schrter 7#hi7 p4 #cb1 fig4 #ah ,b4 #djb ,cash and ,hick 7#gh7 ,pl4 ,,vi4 fig4 #c4 #djc ,gppert and ,menge 7#hc7 ,pl4 ,,xiii4 fig4 #ajf4 #djd ,harper 7#ie74 #dje e4g4 ,ludwig 7#eg7 ,pl4 ,,xvi4 fig4 #a4 #djf ,potoni 7#ic7 p4 #bg1 ,pl4 ,i4 fig4 #h4 #djg ,references are given by ,potoni to illustrations by ,zeiller 7#ib7 ,pl4 ,,xv4 fig4 #f1 ,grand' ,eury 7#gg7 ,pl4 ,,xxxiii4 fig4 #g1 and others in which possible fungi are represented4 #djh ,engelhardt 7#hg74 #dji ,for figures of the ,coccineae1 see ,comstock 7#hh71 ,maskell 7#hg71 ,judeich and ,nitsche 7#ie7 c4 #daj ,massalongo 7#ei7 ,pl4 ,i4 fig4 #a1 p4 #hg4 #daa ,meschinelli 7#ib74 #dab ,james1 ,j4 ,f4 7#ic74 #dac ,lesquereux 7#hg74 #dad ,herzer 7#ic74 #dae ,conwentz 7#ij7 ,pl4 ,,xii4 fig4 #e4 #daf ,feilden1 ,h4 ,w4 7#if72 ,seward 7#if7 p4 #fb1 appendix to ,feilden's paper4 ,i am indebted to ,dr ,bonney for an opportunity of examining the plant remains from the ,feilden collection4 #dag ,hartig 7#gh74 #dah ,conwentz 7#hj7 ,pl4 ,v4 fig4 #ag4 #dai ,carruthers 7#gj7 ,pl4 ,,xxv4 fig4 #c4 #dbj ,renault 7#if7 p4 #dbg1 fig4 #hj1 d4 #dba ibid4 p4 #dbg1 fig4 #hj1 a-c4 #dbb p4 #abg4 #dbc ,etheridge 7#ib7 ,pl4 ,,vii4 #dbd ,hartig 7#gh7 and 7#id71 ,gppert and ,menge 7#hc74 #dbe ,renault 7#if7 p4 #dbe1 fig4 #gh4 #dbf ,fischer in ,rabenhorst1 vol4 i4 7#ib7 p4 #add4 #dbg ,carruthers 7#gf7 p4 #bb1 fig4 #a4 #dbh ,smith1 ,w4 ,o4 7#gg7 p4 #dii4 #dbi ,williamson 7#ha7 ,pl4 ,,xlviii4 p4 #cja4 #dcj ,renault 7#if7 p4 #dci1 figs4 #hh and #hi4 #dca ,cash and ,hick 7#gh74 #dcb ,cash and ,hick1 ,pl4 ,,vi4 fig4 #c4 #dcc ,felix 7#id7 p4 #bgf1 ,pl4 ,,xix4 fig4 #a4 #dcd ibid4 p4 #bgd1 ,pl4 ,,xix4 figs4 #e and #f4 #dce ,williamson 7#gh7 and 7#hj74 #dcf ,conwentz 7#ij7 p4 #aai1 ,pl4 ,,xi4 pp4 #b1 #c1 ,pl4 ,,xv4 fig4 #h4 #dcg ,migula 7#ij7 in ,rabenhorst's ,kryptogamen ,flora1 vol4 ,v4 #dch ,vaillant 7#agai7 p4 #ag4 #dci ,migula 7#ij7 p4 #ec4 #ddj ,knowlton 7#hi74 #dda ,meek 7#gc7 p4 #bai4 #ddb ,saporta 7#gc7 p4 #bad1 ,pl4 ,,ix4 figs4 #h-aa4 #ddc ,seward 7#id7 p4 #ac1 fig4 #a4 #ddd ,woodward1 ,h4 ,b4 7#ie7 pp1 #bcd1 #bfa1 etc4 #dde ,forbes1 ,e4 7#ef7 p4 #afj1 ,pl4 ,,vii4 #ddf ,vide p4 #fi1 fig4 #aj4 #ddg ,lyell 7#bi74 #ddh ,skertchly 7#gg7 p4 #fj4 #ddi ,schiffner and ,mller in ,engler and ,prantl 7#ie71 ,campbell 7#ie71 ,dixon and ,jameson 7#if7 are among the best of modern writers on the ,bryophyta4 #dej ,hooker1 ,j4 ,d4 7#ia7 p4 #eac4 #dea ,schiffner 7#ie7 p4 #adj4 #deb ,hooker1 ,w4 ,j4 7#bj7 ,pl4 ,,clxiii4 #dec ,bennett and ,brown 7#ch71 ,pl4 ,v4 #ded ,bennett and ,brown 7#ch7 p4 #ce4 #dee ,nathorst 7#ij7 ,pl4 ,,ii4 fig4 #c4 #def ,lindenberg 7#ci7 ,pl4 ,,ix4 fig4 #a4 #deg ,zeiller 7#ib7 ,pl4 ,i4 figs4 #g and #h4 #deh ,fliche and ,bleicher 7#ha74 #dei ,brongniart 7#di7 p4 #ab4 #dfj ,seward 7#id7 p4 #ag4 #dfa ,leckenby 7#fd7 ,pl4 ,,xi4 fig4 #c4 #dfb ,seward loc4 cit4 p4 #ah1 ,pl4 ,i4 fig4 #c4 #dfc ,raciborski 7#id7 p4 #aj1 ,pl4 ,,vii4 figs4 #a-c4 #dfd ,brongniart 7#di7 p4 #ab4 #dfe ,saporta 7#fh7 p4 #cjh1 ,pl4 ,i4 figs4 #a-h4 ,vide also ,watelet 7#ff7 p4 #dj1 ,pl4 ,,xi4 fig4 #f4 #dff ,gppert and ,berendt 7#de7 ,pl4 ,,vi4 and 7#ec74 #dfg ,gottsche 7#hf74 #dfh ,schimper 7#fe7 ,pl4 ,,iii4 #dfi ,greville 7#dg7 ,pl4 ,,xii4 #dgj ,brown1 ,r4 7#aa7 ,pl4 ,,xxiii4 #dga ,hooker1 ,w4 ,j4 7#bj7 ,pl4 ,,clxii4 #dgb ,limpricht 7#ij7 p4 #fg4 #dgc ,brongniart 7#bh7 p4 #ic4 #dgd ,renault and ,zeiller 7#hh7 p4 #hd1 ,pl4 ,,xli4 figs4 #b-d4 #dge ,solms-,laubach 7#ia7 p4 #ahf4 #dgf ,lesquereux 7#gi7 ,pl4 ,,lxii4 fig4 #a4 #dgg ,heer 7#fe7 p4 #hi4 #dgh ,buckman 7#ej7 #a4 #dgi ,gardner 7#hf7 p4 #bjc4 #dhj ,ludwig 7#ei7 p4 #afe1 ,pl4 ,,lxiii4 fig4 #i4 #dha ,schimper and ,schenk 7#ij7 p4 #ge4 #dhb e4g4 the ,fern ,trichomanes ,goebelianum ,gies4 ,giesenhagen 7#ib7 p4 #aeg4 #dhc ,scott 7#if7 a text-book for elementary students2 a full account is given of ,equisetum and other genera of primary importance4 ,vines 7#ie7 ,part iii4 ,campbell 7#ie71 ,luerssen 7#hi7 in ,rabenhorst's ,kryptogamen-,flora1 vol4 ,,iii41 ,van ,tieghem 7#ia71 de ,bary 7#hd71 ,baker 7#hg74 #dhd ,wallace 7#hf7 p4 #aag4 #dhe ,baker 7#hg7 p4 #d4 ,hooker1 ,w4 ,j4 7#fa7 ,pl4 ,,lxxiv4 ,vide also ,milde 7#fg7 for figures of ,equisetum4 #dhf ,seeman 7#fe74 #dhg ,duval-,jouve 7#fd7 ,pl4 ,i4 fig4 #e4 #dhh ,milde 7#fg7 ,pl4 ,,xix4 fig4 #h4 #dhi ibid4 ,pl4 ,,xxxi4 fig4 #c4 #dij ,cormack 7#ic7 p4 #ga4 #dia ,williamson and ,scott 7#id7 p4 #hgg4 ,these authors1 in referring to ,cormack's description of the secondary nodal wood of ,e4 maximum1 express doubts as to the existence of such secondary growth in all species of the genus4 #dib ,pfitzer 7#fg74 #dic ,strasburger 7#ia7 p4 #ddc4 #did ,strasburger 7#ia7 p4 #dce4 #die ,bower 7#id7 p4 #die4 #dif ,sternberg 7#ch7 p4 #dc4 #dig ,scott 7#ig74 ,this genus will be described in ,volume ,,ii4 #dih ,potoni 7#ic7 ,pl4 ,,xxv4 fig4 #a;a4 #dii ibid4 p4 #agi4 ,vide also ,potoni 7#ib74 #ejj ,zeiller 7#ib7 p4 #ef1 ,pl4 ,,xii4 ,other similar leaf-sheaths have been figured by ,germar 7#dd7 ,pl4 ,x41 ,schimper 7#gd7 ,pl4 ,,xvii4 and others4 #eja ,grand',eury 7#ij7 p4 #bbc1 ,pl4 ,,xv4 fig4 #af4 #ejb ,renault 7#ic7 ,pl4 ,,xlii4 figs4 #f and #g4 #ejc ,kidston 7#ib74 #ejd ,zeiller 7#ie74 #eje ,potoni 7#ic7 p4 #agi1 ,pl4 ,,xxv4 figs4 #b-d4 #ejf ,renault and ,zeiller 7#hh7 p4 #cif1 ,pl4 ,,lvii4 fig4 #g4 #ejg ,lindley and ,hutton 7#ca7 ,pl4 ,,cxiv4 #ejh ,schoenlein and ,schenk 7#fe7 ,pl4 ,v4 fig4 #a4 #eji ,schimper and ,mougeot 7#dd7 p4 #eh1 ,pl4 ,,xxix4 #eaj ,jger 7#bg74 #eaa ,schimper 7#gd7 ,pls4 ,,ix-,,xi4 #eab ,schimper and ,koechlin-,schlumberger 7#fb74 #eac ,schoenlein and ,schenk 7#fe7 ,pls4 ,i-,,iv4 #ead ,brongniart 7#bh7 p4 #aae1 ,pl4 ,,xiii4 #eae ,young and ,bird 7#bb7 p4 #ahe1 ,pl4 ,,iii4 fig4 #c4 #eaf ,knig1 in ,murchison 7#bi7 p4 #bic1 ,pl4 ,,xxxii4 #eag ,murchison 7#bi7 p4 #cfh4 #eah ,bunbury 7#ea7 p4 #ahi4 #eai ,schimper 7#fi7 p4 #bfg4 #ebj ,zigno 7#ef7 ,pl4 ,,iii4 fig4 #a1 p4 #de4 #eba ,gardner 7#hf7 ,pl4 ,,ix4 fig4 #c4 #ebb ,williamson 7#hc7 p4 #d4 #ebc ,williamson and ,scott 7#id7 p4 #hhi1 ,pl4 ,,lxxix4 fig4 #ai4 #ebd ,phillips ,j4 7#bi7 ,pl4 ,x4 fig4 #ac4 #ebe ,lindley and ,hutton 7#ca7 ,pl4 ,,clxxxvi4 #ebf ,bunbury 7#ea7 p4 #ahi4 #ebg ,zigno 7#ef7 ,pl4 ,,iii4 fig4 #c1 p4 #df4 #ebh ,heer 7#gg7 p4 #dc1 ,pl4 ,,iv4 #ebi ,schimper 7#fi7 p4 #bhd4 ,vide also ,nathorst 7#hj7 p4 #ed4 #ecj ,andrae 7#ec7 ,pl4 ,,vi4 figs4 #a-e4 #eca ,solms-,laubach 7#ia7 p4 #ahj4 #ecb cf4 p4 #bhc4 #ecc ,there is a similar specimen in the ,oxford ,museum4 #ecd ,since this was written ,i have found a specimen of ,equisetites lateralis in the ,woodwardian ,museum1 in which a diaphragm like that in fig4 #fd1 ,c1 occurs in the centre of a flattened leaf-sheath similar to that of fig4 #fd1 ,b4 #ece ,buckman 7#ej7 p4 #dad4 #ecf ,schenk 7#fg74 #ecg ,tenison-,woods 7#hc71 ,pl4 ,,vi4 figs4 #e and #f4 ,specimen no4 ,v4 #cceh in the ,british ,museum4 #ech ,dunker 7#df7 p4 #b1 ,pl4 ,v4 fig4 #g4 #eci ,seward 7#id7 p4 #cj4 #edj ,seward 7#id7 p4 #cc4 #eda ,heer 7#ee7 vol4 ,,iii4 p4 #aeh1 ,pl4 ,,cxlv4 #edb ,heer 7#gg7 p4 #ii1 ,pl4 ,,xxii4 #edc ,vide ,saporta 7#gc7 p4 #bbg4 #edd ,the distribution will be dealt with in ,volume ,,ii4 #ede ,brongniart 7#bh7 p4 #aea4 #edf ,schmalhausen 7#gi7 p4 #ab1 ,pl4 ,i4 figs4 #a-c4 #edg ,solms-,laubach 7#ia7 p4 #aha4 #edh ,zeiller 7#if74 #edi ,zeiller 7#if74 #eej ibid4 7#if74 #eea ,letter1 ,july #cj1 #ahig4 #eeb ,on this character of ,annularian leaves1 vide p4 #ccg4 #eec ,gppert 7#de7 p4 #cgi1 ,pl4 ,,xxv4 figs4 #a1 #b4 #eed ,schmalhausen 7#gi7 p4 #ab4 #eee ,mc,coy 7#dg7 ,pl4 ,,xi4 fig4 #g4 #eef ,bunbury 7#fa7 ,pl4 ,,xi4 fig4 #a4 #eeg ,seward 7#ig7 p4 #cbd1 ,pl4 ,,xxiv4 fig4 #a4 #eeh ,feistmantel 7#ha7 ,pl4 ,,ix4 ,a4 fig4 #g1 c4 #eei ibid4 7#ij7 ,pl4 ,,xiv4 fig4 #e4 #efj ,bunbury 7#fa7 ,pl4 ,,xi4 fig4 #a4 #efa ,solms-,laubach 7#ia7 p4 #aha1 fig4 #ag4 #efb ,heer 7#hb7 p4 #i4 #efc ,potoni 7#if7 p4 #aae1 fig4 #c4 #efd ,zigno 7#ef7 ,pl4 ,,vii4 p4 #ei4 #efe ,bunbury 7#fa74 #eff ,feistmantel 7#ha71 ,pl4 ,,xii4 ,a4 #efg ,brongniart 7#bh7 p4 #aeb4 #efh ,bunbury 7#fa74 #efi ,grand',eury 7#ij7 p4 #bba4 #egj ,etheridge 7#ie74 #ega ,weiss 7#gf7 p4 #hh4 #egb ,heer 7#gg7 p4 #dc1 ,pl4 ,,iv4 7#gh7 p4 #d1 ,pl4 ,i4 #egc ,tenison-,woods 7#hc7 ,pl4 ,,ix4 fig4 #b4 #egd ,brongniart 7#bh7 p4 #abh4 #ege ,schimper and ,mougeot 7#dd7 p4 #dh1 ,pls4 ,,xxiv-,,xxvi4 #egf ,feistmantel 7#ha7 p4 #ei1 ,pls4 ,i4 ,a-,x4 ,a4 #egg ante1 p4 #bhd4 #egh ,schimper and ,mougeot 7#dd7 p4 #ej1 ,pls4 ,,xxiv-,,xxvi4 #egi ,seward 7#ig74 #ehj ,scheuchzer 7#agbc71 p4 #ai1 ,pl4 ,,iv4 fig4 #a4 #eha ,volkmann 7#agbj71 p4 #aaj1 ,pl4 ,,xiii4 fig4 #g4 #ehb ,woodward1 ,j4 7#agbh71 ,pt4 ,,ii4 p4 #aj4 #ehc ,schulze1 ,c4 ,f4 7#agee71 ,pl4 ,,ii4 fig4 #a4 #ehd ,suckow 7#aghd71 p4 #cfc4 #ehe ,steinhauer 7#ah71 ,pls4 ,v4 and ,,vi4 #ehf ,martin 7#ji71 ,pls4 ,,viii4 ,,xxv4 and ,,xxvi4 #ehg ,artie 7#be74 #ehh ,brongniart 7#bb71 p4 #bah4 #ehi ,brongniart 7#bh71 p4 #cd4 #eij ,lindley and ,hutton 7#ca74 #eia ,cotta 7#ej74 ,i am indebted to ,prof4 ,stenzel of ,breslau for calling my attention to the fact that ,cotta's work appeared in #ahcb1 but in #ahej the same work was sold with a new title-page bearing this date4 #eib ,unger 7#dj74 #eic ,petzholdt 7#da74 #eid ,unger 7#dd74 #eie ,brongniart 7#di71 p4 #di4 #eif ,e4g4 ,isoetes1 ,botrychium1 c4 #eig ,mougeot 7#eb74 #eih ,gppert 7#fd71 p4 #ahc4 #eii 1 joint2 1 ,pine-tree4 #fjj ,the original specimens described by ,gppert are in the rich palaeobotanical ,collection of the ,breslau ,museum4 #fja ,williamson 7#ga71 p4 #agd4 #fjb vide ,solms-,laubach 7#if74 #fjc ,letter1 ,november #ahig4 #fjd ,vide p4 #caj4 #fje ,hick 7#id71 ,pl4 ,,ix4 fig4 #a4 #fjf ,on this point vide ,williamson and ,scott 7#id71 p4 #hfi4 #fjg ,williamson and ,scott1 loc4 cit4 p4 #hgf4 #fjh ,renault 7#ic71 ,pl4 ,,xlvii4 fig4 #d4 #fji ,stur 7#hg74 #faj ,the term primary ray may be conveniently restricted to the truly primary interfascicular tissue1 and the term principal ray may be used for the outward extension of the primary rays by the cambium ,williamson and ,scott 7#id71 p4 #hgh4 #faa ,binney 7#fh74 #fab ,ettingshausen 7#ee74 #fac ,the sections of fossil plants described by ,binney were presented to the ,woodwardian ,museum1 ,cambridge1 by his son 7,mr ,j4 ,binney74 #fad ,vide footnote1 p4 #caa4 #fae ,williamson 7#hc71 ,pl4 ,,xxxiii4 fig4 #ai4 #faf ,williamson 7#gh71 p4 #cbc1 ,pl4 ,,xx4 figs4 #ad and #ae4 #fag ,williamson and ,scott 7#id71 p4 #hhh4 #fah ,hartig 7#id71 pp4 #adi1 #big1 etc4 #fai ,renault 7#if71 p4 #ia4 #fbj ,williamson and ,scott1 loc4 cit4 p4 #hic4 ,vide specimens #acc99-ace99 in the ,williamson ,collection4 #fba ,e4g4 specimen #acb999999 in the ,williamson ,collection4 #fbb ,vide ,williamson 7#ga71 ,pl4 ,,xxviii4 fig4 #ch2 7#ga71 ,pl4 ,,iv4 fig4 #ae2 7#gh71 ,pl4 ,,xxi4 figs4 #bf-bh4 ,williamson and ,scott 7#id71 ,pl4 ,,lxxii4 figs4 #e and #f4 ,renault 7#ic71 ,pl4 ,,xlv4 figs4 #d-f1 etc4 ,felix 7#if71 ,pl4 ,,iv4 figs4 #b and #c4 #fbc ,strasburger 7#ia71 ,pl4 ,,ii4 fig4 #dj4 #fbd ,williamson 7#gh74 #fbe ,williamson 7#ga71 p4 #ejg4 #fbf ,williamson 7#ga71 ,pl4 ,i4 fig4 #a2 7#gh71 ,pl4 ,,xxi4 fig4 #ca4 #fbg ,lyell 7#ee71 p4 #cfh4 #fbh ,williamson 7#if71 p4 #aid4 #fbi ,vide specimens #ae-ag1 etc4 in the ,williamson ,collection4 #fcj ,the stem of fig4 #hc is an example of ,arthrodendron1 but the appearance of the secondary xylem agrees with that in some forms of ,arthropitys4 #fca ,for figures of this type of stem vide ,gppert 7#fd72 ,cotta 7#ej71 ,pl4 ,,xv4 7specimens #acghg in the ,british ,museum ,collection72 ,mougeot 7#eb71 ,pl4 ,v42 ,stur 7#hg71 pp4 #bg-ca2 ,renault 7#ic71 ,pls4 ,,xliv4 and ,,xlv4 etc4 #fcb ,williamson 7#ga71 7#ga71 7#hg71 fig4 #e4 #fcc ,williamson and ,scott 7#id71 p4 #hgi #fcd ,vide ,williamson 7#hg74 ,in this paper ,williamson compares the three subgenera of ,calamite stems4 ,renault and ,zeiller 7#hh71 ,pl4 ,,lxxv4 ,renault 7#ic71 ,pls4 ,,lviii4 and ,,lix4 #fce ,renault 7#if71 p4 #abe2 7#ic71 ,pl4 ,,lix4 fig4 #b4 #fcf ,lindley and ,hutton 7#ca71 ,pls4 ,,cxiv41 ,,cxc4 etc4 ,most of the specimens figured by these authors are in the ,newcastle ,natural ,history ,museum4 ,for notes on the type-specimens of ,lindley and ,hutton1 vide ,howse 7#hh7 and ,kidston 7#ij74 #fcg ,weiss 7#hh71 ,stur 7#hg71 etc4 #fch ,vide1 p4 #cfg4 #fci ,ante1 p4 #bfj4 #fdj ,hick 7#ie74 #fda ,brongniart 7#bb71 p4 #bce4 #fdb ,schlotheim 7#bj74 #fdc ,brongniart 7#bh71 p4 #aei4 #fdd ,lindley and ,hutton 7#ca71 ,pl4 ,,cxc4 #fde ,ettingshausen 7#ee74 #fdf ,schimper 7#fi71 p4 #cbc4 #fdg ,grand',eury 7#ij74 #fdh ,martin 7#ji71 ,pl4 ,,xx4 figs4 #d and #f4 #fdi ,schlotheim 7#bj71 p4 #cig4 #fej ,sternberg 7#be71 p4 xxviii4 #fea ,brongniart 7#bh71 p4 #aed4 #feb ,lindley and ,hutton 7#ca71 ,pl4 ,,cxci4 #fec ,ettingshausen 7#ee71 p4 #bh4 #fed ,schimper 7#fi71 ,pls4 ,,xxii4 and ,,xxvi4 fig4 #a4 #fee ,for other lists and synonyms1 vide ,zeiller 7#hh71 p4 #cfh1 and ,kidston 7#hf71 p4 #ch and 7#ic71 p4 #caf1 also ,potoni 7#ic71 p4 #afb4 #fef ,sternberg 7#bj74 #feg ,brongniart 7#bh71 p4 #aee4 #feh ,lehmann 7#agef71 p4 #abg4 ,vide also ,volkmanns 7#agbj71 ,pl4 ,,xv4 p4 #aac4 #fei ,potoni 7#ic71 pp4 #afi et seq41 ,pl4 ,,xxiv4 #ffj ,dawson 7#ga74 #ffa ,nicholson 7#fi7 ,pl4 ,,xviii4 ,b4 ,nicholson's specimens are in the ,woodwardian ,museum1 ,cambridge4 #ffb ,schlotheim 7#bj71 p4 #cig4 #ffc ,sternberg 7#bf71 p4 xxviii4 #ffd ,brongniart 7#bh71 p4 #aef4 #ffe ,lindley and ,hutton 7#ca71 ,pl4 ,,cxxiv4 #fff ,binney 7#fh71 ,pl4 ,,vi4 fig4 #c4 #ffg ,stur 7#hg71 ,pl4 ,,xvi b1 and ,pls4 ,,iv b and ,,xiii4 #ffh ,scheuchzer 7#agbc71 p4 #fc1 ,pl4 ,,xiii4 fig4 #c4 #ffi ,potoni 7#ic71 p4 #aff4 #fgj ,vide pp4 #cea et seq4 #fga ,renault 7#if71 p4 #ff2 7#ic71 ,pl4 ,,xxviii4 #fgb ,one of the finest specimens of ,annularia stellata is figured by ,stur 7#hg71 ,pl4 ,,xvi b2 it is in the ,leipzig ,museum4 ,,vide also ,schenk 7#hc71 ,pl4 ,,xxxix42 ,germar 7#dd71 ,pl4 ,,ix42 ,renault and ,zeiller 7#hh71 ,pls4 ,,xlv4 and ,,xlvi4 ,there are some well-preserved impressions of ,a4 stellata in the ,british ,museum from ,radstock1 ,newcastle and elsewhere4 #fgc ,zenker 7#cc71 ,pl4 ,v4 pp4 #f-i4 #fgd ,heer 7#fe71 fig4 #f1 p4 #i1 and other authors4 #fge ,weiss 7#gf71 p4 #bg1 ,pl4 ,,iii4 fig4 #b4 #fgf ,lhwyd 7#afii71 ,pl4 ,v4 fig4 #bjb4 #fgg ,sterzel 7#hb74 #fgh ,vide ,weiss 7#gf71 ,pl4 ,,iii4 and ,weiss 7#hd71 p4 #agh4 #fgi ,williamson 7#ga71 p4 #dhg1 ,pls4 ,,xxv4 and ,,xxvi4 #fhj ,ibid4 7#gh71 p4 #cai1 ,pl4 ,,xix4 #fha ,cash and ,hick 7#ha71 p4 #djj4 #fhb ,williamson 7#ha71 vide also ,spencer 7#ha74 #fhc ,spencer 7#hc71 p4 #dei4 #fhd ,williamson 7#hc71 p4 #dei1 ,pls4 ,,xxvii4-,,xxx4 #fhe ,renault 7#he74 #fhf ,lindley and ,hutton 7#ca71 ,pls4 ,,lxxviii4 and ,,lxxix4 7,the specimens are figured in a reversed position47 #fhg ,binney 7#fh71 p4 #e1 fig4 #a4 #fhh ,grand',eury 7#gg71 ,pls4 ,i4 and ,,ii42 7#hg71 ,pls4 ,,xxvii41 ,,xxviii4 #fhi ,weiss 7#hd71 ,pls4 ,,ii4-,,iv41 ,,viii4 and ,,ix4 #fij ,stur 7#hg71 ,pls4 ,,iii41 ,,vi41 ,,vii41 etc42 ,zeiller 7#hf71 ,pl4 ,,liv4 #fia ,weiss 7#gf71 7#hd74 #fib ,for references1 vide ,kidston 7#hf71 p4 #eh4 #fic ,artis 7#be71 ,pl4 ,v4 #fid ,williamson and ,scott 7#ie71 p4 #fid4 #fie ,williamson 7#hc71 ,pl4 ,,xxix4 fig4 #g4 #fif ,williamson and ,scott 7#ie71 ,pls4 ,,xv4-,,xvii4 #fig ,for figures vide ,williamson1 loc4 cit41 ,williamson and ,scott1 and ,renault 7#he71 7#ic74 #fih ,e4g4 ,schenk 7#ij7 in ,zittel's ,handbuch1 p4 #bcg4 #fii ,williamson and ,scott1 loc4 cit4 p4 #fhi4 #gjj de ,bary 7#hd71 p4 #dgd2 van ,tieghem 7#ia71 p4 #gbj4 #gja ,renault 7#if71 pp4 #aah1 #abf2 7#ic71 ,pl4 ,,lv4 #gjb ,carruthers 7#fg71 ,pl4 ,,lxx4 #gjc ,sternberg 7#be71 ,pl4 ,,xlviii4 and ,,li4 #gjd ,brongniart 7#di71 p4 #ea4 #gje ,binney 7#fh71 p4 #bc1 ,pls4 ,,iv4 and ,v4 #gjf ,schimper 7#fi71 p4 #ccj4 #gjg ,for figures and descriptions of this type of cone vide ,williamson 7#gc71 7#hj71 7#hi72 ,hick 7#ic71 7#id7 and ,williamson and ,scott 7#id74 #gjh ,weiss 7#hd71 ,pls4 ,,xxii4--,,xxiv4 #gji ,williamson and ,scott 7#id71 p4 #iaa1 ,pls4 ,,lxxxi4 and ,,lxxxii4 #gaj ,vide ,heinricher 7#hb72 ,bower 7#id71 p4 #die2 ,campbell 7#ie71 pp4 #cif1 #ejc4 #gaa ,williamson 7#ha71 ,pl4 ,,liv4 #gab ,an excellent figure illustrating the co-existence of heterospory and secondary thickening is given by ,williamson and ,scott1 loc4 cit41 ,pl4 ,,lxxxii4 fig4 #cf4 #gac ,weiss 7#gf71 p4 #ajc4 #gad ,williamson 7#ga74 #gae ,ibid4 7#hh74 #gaf ,williamson and ,scott 7#id71 p4 #ijj4 #gag ,weiss 7#hd71 ,pl4 ,,xxi4 fig4 #d4 #gah ,williamson 7#gd71 ,pl4 ,v4 fig4 #cb4 #gai ,williamson 7#hh71 ,pl4 ,,ix4 fig4 #bj4 #gbj ,e4g4 ,renault 7#hb71 ,pl4 ,,xix4 fig4 #a2 7#if71 ,pl4 ,,xxix4 figs4 #a and #d4 #gba ,williamson 7#hh71 ,pl4 ,,viii4 figs4 #a and #d4 #gbb ,renault 7#ic71 ,pl4 ,,xxix4 fig4 #g4 #gbc ,solms-,laubach 7#ia71 p4 #cbe4 #gbd ,weiss 7#hd7 p4 #afa4 ,solms-,laubach1 loc4 cit4 p4 #cbf4 #gbe ,e4g4 ,volkmannia ,ludwigi ,carr41 also ,volkmannia elongata ,presl4 ,solms 7#ia71 p4 #ccb and ,weiss 7#gf71 p4 #ajh4 #gbf ,e4g4 ,brukmannia ,grand',euryi ,ren4 ,renault 7#gf74 #gbg ,weiss 7#hd71 p4 #aij4 #gbh ,weiss 7#gf71 p4 #a4 #gbi ,weiss 7#hd71 p4 #afa4 #gcj ,renault 7#hb71 p4 #aci2 7#gf74 #gca ,solms-,laubach 7#ia71 p4 #ccj4 #gcb ,schenk 7#hh71 p4 #acb2 7#hc71 p4 #bcb4 #gcc ,weiss 7#hd71 p4 #afa4 #gcd ,e4g4 ,volkmannia gracilis ,sternb4 ,renault 7#gf71 ,pl4 ,,ii44 #gce ,schimper 7#fi71 p4 #ccb4 ,vide also ,renault and ,zeiller 7#hh71 p4 #dbj4 #gcf ,renault 7#hb71 p4 #abj1 ,pl4 ,,xix42 7#ic71 ,pl4 ,,xxix4 figs4 #h-ad2 7#if71 p4 #gg4 #gcg ,weiss 7#hd71 p4 #ih1 ,pl4 ,,xx4 etc4 #gch ,sterzel 7#hb74 #gci ,renault and ,zeiller 7#hh71 ,pl4 ,,xlvi4 fig4 #g4 #gdj ,kidston 7#hf71 p4 #dg2 7#ic71 p4 #cai4 ,vide also ,renault 7#ic71 ,pl4 ,,xxviii4 #gda ,renault and ,zeiller 7#hh71 ,pl4 ,,xlv4 #gdb ,solms-,laubach 7#ia71 p4 #cci4 ,weiss 7#hd71 p4 #aei4 #gdc ,weiss 7#hd71 ,pl4 ,,xx4 fig4 #f4 #gdd ,weiss 7#hd71 ,pl4 ,,xx4 fig4 #g2 ,pl4 ,,xxi4 fig4 #d4 #gde ,ibid4 ,pls4 ,,xiv4 and ,,xv4 ,cf4 also ,stur 7#hg71 ,pls4 ,,vi4 and ,,vii b1 and ,lesquereux 7#hd71 ,pl4 ,,xc4 fig4 #a4 #gdf ,grand',eury 7#ij71 pp4 #bje1 #bjh4 ,renault and ,zeiller 7#hh71 ,pl4 ,,li4 #gdg ,vide ,unger 7#ej71 p4 #fc4 #gdh ,weiss1 loc4 cit4 #gdi ,solms-,laubach 7#ia71 p4 #cbh4 #gej ,schenk 7#hc71 p4 #bcd4 #gea ,weiss 7#gf71 p4 #hh2 7#hd71 p4 #afb4 ,solms-,laubach1 loc4 cit4 p4 #ccd1 fig4 #dg4 #geb ,renault 7#if71 p4 #acb4 #gec ,zeiller 7#hh71 ,pl4 ,,liv4 fig4 #d4 #ged ,stur 7#hg71 p4 #ag4 #gee ,lindley and ,hutton 7#ca71 ,pl4 ,,cxlii ,b4 ,the original specimen is in the ,university ,college ,collection1 ,london4 #gef ,nathorst 7#id71 p4 #ef1 ,pl4 ,,xv4 figs4 #a and #b4 #geg ,seward 7#hh74 #geh ,weiss 7#hd71 p4 #ed4 #gei ,zeiller 7#hh71 p4 #cbi4 #gfj ,weiss 7#gf71 p4 #aag2 7#hd71 p4 #ee4 #gfa ,weiss 7#hd71 p4 #ic1 ,pl4 ,,xi4 fig4 #a4 #gfb ,vide ,weiss 7#hd71 ,pl4 ,,xxv4 fig4 #b2 ,pl4 ,,xvi a1 etc4 #gfc ,weiss 7#gf71 ,pl4 ,,xvii4 fig4 #a4 #gfd ,weiss 7#hd71 ,pl4 ,i4 #gfe ,grand',eury 7#ij71 p4 #bjh1 and 7#gg71 ,pl4 ,v4 #gff ,lindley and ,hutton 7#ca71 ,pl4 ,,cxc4 #gfg ,stur 7#hg71 ,pl4 ,v4 fig4 #a4 #gfh ,grand',eury 7#gg71 ,pl4 ,,iv4 #gfi ,stur 7#hg71 ,pl4 ,,xvii4 #ggj ,renault 7#hb71 ,pl4 ,,xvii4 fig4 #b4 #gga ,renault and ,zeiller 7#hh71 ,pt4 ,,ii4 p4 #dcd1 ,pls4 ,,lii4 and ,,liii4 #ggb ,stur 7#hg71 p4 #cg1 fig4 #ag4 ,vide also ,grand',eury 7#ij71 p4 #bjh4 #ggc ,stur1 loc4 cit4 #ggd ,weiss 7#hd71 p4 #fa4 #gge ,vide ,grand',eury 7#gg71 ,pl4 ,v4 fig4 #e4 #ggf ,weiss1 loc4 cit4 ,pl4 ,,xxi4 fig4 #e4 #ggg ,stur 7#hg71 ,pl4 ,,xi4 fig4 #a4 #ggh ,renault and ,zeiller 7#hh71 ,pt4 ,,ii4 ,pl4 ,,li4 p4 #dbc4 #ggi ,lindley and ,hutton 7#ca71 ,pl4 ,,cxiv4 and ,pl4 ,,cxc4 ,the original specimens are in the ,natural ,history ,museum1 ,newcastle-on-,tyne4 #ghj ,ibid4 ,pl4 ,,cxxx4 and ,feistmantel 7#ge71 ,pl4 ,i4 fig4 #h4 #gha ,lesquereux 7#gi71 ,pl4 ,,xiii4 fig4 #ad4 #ghb ,salter 7#fc71 figs4 #f and #g4 ,vide also ,carruthers in ,woodward1 ,h4 7#gb71 p4 #afh4 #ghc ,grand',eury 7#fi72 vide also 7#gg7 and 7#ij74 #ghd ,renault and ,zeiller 7#hh71 ,pt4 ,,ii4 ,pls4 ,,lii4 and ,,ciii4 #ghe ,ibid4 ,pl4 ,,li4 #ghf ,sternberg 7#ba71 ,pl4 ,,xii4 #ghg ,weiss 7#hd71 p4 #fa4 #ghh ,ettingshausen 7#ee71 ,pl4 ,i4 fig4 #d4 #ghi ,ettingshausen1 loc4 cit4 #gij ,grand',eury 7#fi71 p4 #gji4 #gia ,feistmantel 7#ge71 ,pl4 ,i4 fig4 #h4 #gib ,williamson 7#gd71 ,pl4 ,,vii4 fig4 #de4 #gic ,weiss 7#gf71 ,pl4 ,,xvii4 figs4 #a and #b4 #gid ,weiss 7#hd71 ,pl4 ,,xvi a4 figs4 #aj and #aa4 #gie ,ibid4 ,pl4 ,,xxv4 fig4 #b4 #gif ,stur 7#hg71 ,pl4 ,,ii4 etc4 #gig ,zeiller 7#hh71 p4 #cfc1 ,pl4 ,,lvii4 fig4 #a4 #gih ,steinhauer 7#ah71 ,pl4 ,,vi4 fig4 #a4 #gii ,kidston 7#ic71 p4 #caa1 ,pl4 ,,ii4 #hjj ,kidston 7#id71 p4 #bdh4 #hja ,weiss 7#hd71 p4 #aai4 #hjb ,steinhauer 7#ah71 ,pl4 ,v4 figs4 #a and #b4 #hjc ,artis 7#be71 ,pl4 ,,xxiv4 #hjd ,brongniart 7#bh71 ,pls4 ,,xv4 and ,,xvi4 #hje ,lindley and ,hutton 7#ca71 ,pl4 ,,lxxix4 #hjf ,kidston 7#ic71 p4 #cad2 7#hf71 p4 #bd4 #hjg ,zeiller 7#hh71 p4 #ccc4 #hjh ,lindley and ,hutton 7#ca71 ,pl4 ,,lxxix4 #hji ,weiss 7#hd71 ,pl4 ,,iv4 fig4 #a4 #haj ,renault and ,zeiller 7#hh71 p4 #che4 #haa ,grand',eury 7#ij71 p4 #bad4 #hab ,stur 7#hg71 p4 #afj1 ,pl4 ,,ix4 fig4 #b4 #hac ,kidston 7#id71 p4 #bdi4 #had ,grand',eury 7#hi71 p4 #ajhg4 #hae ,zeiller 7#hh71 p4 #cee4 #haf ,weiss 7#hd71 p4 #if4 #hag ,sterzel 7#ic71 p4 #ff4 #hah ,zeiller1 loc4 cit4 p4 #cec4 #hai ,sternberg 7#be71 ,pl4 ,,xlix4 fig4 #e4 #hbj ,brongniart 7#bh71 p4 #abh1 ,pl4 ,,xix4 #hba ,germar and ,kaulfuss 7#ca71 p4 #bba1 ,pl4 ,,xlv4 fig4 #a4 #hbb ,lindley and ,hutton 7#ca71 ,pl4 ,,ccxvi4 #hbc ,grand',eury 7#gg71 p4 #bic4 #hbd ,zeiller 7#hj71 ,pl4 ,,clxxiv4 7expl4 plates7 fig4 #c4 #hbe ,weiss 7#hd71 pp4 #aab1 #aac1 #aad4 #hbf ,zeiller 7#hh71 p4 #cec4 #hbg ,kidston 7#id71 p4 #bdi4 #hbh ,grand',eury 7#ij71 p4 #baf 7expl4 plates74 #hbi ,stur 7#hg71 p4 #fh4 #hcj ,stur 7#hg71 ,pl4 ,x4 #hca ,artis 7#be71 ,pl4 ,,ii4 #hcb ,weiss1 loc4 cit4 ,pls4 ,v4 ,,vi4 and ,x4 #hcc ,grand',eury 7#gg71 7#ij74 #hcd ,vide ,stur 7#ge71 etc4 for remarks on the course of the vascular strands4 #hce ,for good figures of the leaves vide ,stur 7#ge71 ,rothpletz 7#hj71 ,ettingshausen 7#ff71 ,solms 7#if74 #hcf ,renault 7#if71 p4 #hj2 7#ic71 ,pls4 ,,xlii4 and ,,xliii4 ,since the above was written an account of the internal structure of ,archaeocalamites has been published by ,solms-,laubach 7#ig72 he describes the wood as being of the ,arthropitys type4 #hcg ,renault1 loc4 cit4 ,pl4 ,,xlii4 figs4 #f and #g4 #hch ,stur 7#ge71 p4 #b1 ,pls4 ,,ii4-,v4 #hci ,an examination of the specimens in the ,museum of the ,austrian ,geology ,survey did not enable me to satisfactorily verify the features of the cone as described by ,stur2 the impressions are far from clear4 #hdj ,kidston 7#hc74 #hda ,vide ,paterson 7#da72 ,lyell 7#fg71 vol4 ,i4 p4 #adi etc4 #hdb ,volkmann 7#agbj71 p4 #ic1 ,pl4 ,,vii4 fig4 #b4 #hdc ,schlotheim 7#bj71 p4 #djb1 ,pl4 ,,xxii4 fig4 #d4 #hdd ,sternberg 7#be74 #hde ,brongniart 7#bh71 p4 #abb1 ,pl4 ,,xxvi4 figs4 #a and #b4 #hdf ,paterson 7#da71 ,pl4 ,,iii4 #hdg ,gppert 7#eb71 ,pls4 ,,iii41 ,v41 ,,vi41 ,,viii41 ,,xxxviii4 #hdh ,ettingshausen 7#ff71 ,pls4 ,i4-,,iv4 #hdi ,feistmantel 7#gc71 ,pl4 ,,xiv4 fig4 #e4 #hej ,zeiller 7#hj71 p4 #ag4 #hea ,binney 7#fh71 p4 #g4 #heb ,stur 7#ge71 p4 #c4 #hec ,kidston 7#hf71 p4 #ce4 #hed ,schimper and ,koechlin-,schlumberger 7#fb71 ,pl4 ,i4 ,the original specimens of ,schimper's figures are in the ,strassburg ,museum4 #hee ,feistmantel 7#gc71 p4 #dia1 ,pl4 ,,xxiv4 figs4 #c and #d4 #hef ,vide specimens #bj ,a1 #bj ,b1 #bd in the ,williamson ,collection4 #heg ,stur 7#ge71 p4 #ag4 #heh ,rothpletz 7#hj71 p4 #h4 #hei ,weiss 7#hd71 p4 #ef4 #hfj ,scheuchzer 7#agbc71 p4 #ai1 ,pl4 ,,iv4 fig4 #a4 #hfa ,schlotheim 7#jd71 ,pl4 ,,ii4 fig4 #bd1 p4 #eg4 #hfb ,sternberg 7#be71 p4 #cb4 #hfc ,brongniart 7#bb71 ,pl4 ,,xiii4 fig4 #h1 p4 #bcd4 #hfd ,ibid4 7#bh71 p4 #fh4 #hfe ,dawson 7#ff71 p4 #aec1 ,pl4 ,,xii4 #hff ,for reference vide an excellent monograph by ,coemans and ,kickx 7#fd71 also ,potoni 7#id74 #hfg e4g4 ,newberry 7#ia74 #hfh ,renault 7#gc71 7#gf71 7#if74 #hfi ,williamson 7#gd71 7#gh74 #hgj ,williamson and ,scott 7#id71 p4 #iai4 #hga ,specimen #ibi in the ,williamson ,cabinet is a longitudinal section of the ,french ,sphenophyllum1 as described by ,renault 7#gf74 #hgb ,williamson and ,scott 7#id71 p4 #ibf4 #hgc ,williamson 7#ia71 p4 #ah4 #hgd ,williamson and ,scott 7#id71 p4 #ibj4 #hge ,williamson 7#ia71 p4 #ab4 #hgf ,ibid4 7#gd74 #hgg ,felix 7#hf71 ,pl4 ,,vi4 fig4 #b4 #hgh ,for figures vide ,renault 7#hb71 ,pl4 ,,xvi4 fig4 #a1 7#gf7 ,pls4 ,,vii4 and ,,ix4 #hgi ,williamson 7#ga74 #hhj ,weiss 7#hd71 p4 #bjj4 #hha ,binney 7#ga74 #hhb ,williamson 7#ia74 #hhc ,zeiller 7#ic74 #hhd ,williamson 7#ib74 #hhe ,potoni 7#id71 fig4 #a4 #hhf ,for a more complete account of this strobilus vide ,zeiller 7#ic71 and ,williamson 7#ia71 etc4 #hhg ,zeiller 7#ic71 p4 #cg4 #hhh ,williamson and ,scott 7#id71 p4 #idc4 #hhi ,scott 7#ig71 p4 #bd4 #hij ,solms-,laubach 7#ie74 #hia ,ibid4 ,pl4 ,x4 fig4 #f4 #hib ,kidston 7#ij74 #hic ,i am indebted to my friend ,mr ,kidston for an opportunity of examining these specimens4 #hid ,vide ,renault 7#gg71 7#if71 p4 #aeh4 ,zeiller 7#ic71 p4 #cd4 ,williamson and ,scott 7#id71 p4 #idb4 #hie ,brongniart 7#bb71 p4 #bcd1 ,pl4 ,,ii4 fig4 #h4 #hif ,brongniart 7#bh71 p4 #fh4 #hig ,bischoff 7#bh71 ,pl4 ,,xiii4 fig4 #a4 #hih ,rmer1 ,f4 7#fb71 p4 #ba1 ,pl4 ,v4 fig4 #b4 #hii ,sterzel 7#hf71 pp4 #bf1 #bg1 etc4 #ijj ,kidston 7#ic71 p4 #ccc4 #ija ,zeiller 7#hh71 p4 #dad4 #ijb ,ibid4 p4 #daa4 #ijc ,weiss 7#hd71 p4 #bja1 ,pl4 ,,xxi4 fig4 #ab4 #ijd ,solms-,laubach 7#ie71 p4 #bcb4 #ije ,geinitz 7#ee71 ,pl4 ,,xx4 fig4 #g4 #ijf ,zeiller 7#hh71 ,pl4 ,,lxiv4 figs4 #c-e1 and 7#ic71 p4 #bd1 ,pl4 ,,ii4 fig4 #d4 #ijg ,stur 7#ge71 p4 #ajh4 #ijh ,stur 7#hg71 ,pl4 ,,xv4 and ,kidston 7#ij71 p4 #ei1 ,pl4 ,i4 #iji ,zeiller 7#hh71 ,pl4 ,,lxii4 figs4 #b-d4 #iaj ,stur 7#hg72 ,williamson 7#gd72 ,seward 7#hi71 etc4 #iaa ,renault 7#hb71 p4 #hd1 and ,newberry 7#ia74 #iab ,kidston 7#ij71 p4 #fb4 #iac ,stur 7#ge71 p4 #aad1 ,pl4 ,,vii4 #iad ,zeiller 7#ic71 p4 #cb4 #iae ,mahr 7#fh71 ,pl4 ,,viii4 #iaf ,zeiller 7#hj71 p4 #cd1 ,pl4 ,,clxi4 fig4 #i4 #iag ,coemans and ,kickx 7#fd72 ,zeiller 7#hj71 7#hh72 ,schimper 7#fi74 #iah ,royle 7#ci71 p4 #dca4 #iai ,for other figures of this plant1 vide ,feistmantel 7#ha71 ,pls4 ,,xi4 ,a and ,,xii4 ,a4 #ibj ,zeiller 7#ia74 #iba ,vide also ,zeiller 7#ib71 p4 #ge4 #ibb ,feistmantel 7#ha71 p4 #fi4 #ibc ,scott 7#ig74 #ibd ,scott 7#if71 p4 #ae4 #ibe ,dawson 7#fa71 p4 #aj1 fig4 #g4 #ibf ,kidston 7#id71 p4 #bej4 #ibg ,kidston 7#id71 p4 #bej4 #ibh ,sterzel 7#ic71 p4 #adc4 #ibi ,zeiller 7#id71 p4 #agb4 #icj ,de ,bary 7#hd71 p4 #dii4 #ica ,westermaier and ,ambronn 7#ha74 #icb ,schwendener 7#gd71 p4 #abd4 ,haberlandt 7#if71 p4 #afe4 ,transcriber's ,notes3 - ,text enclosed by underscores is in italics 7italics74 - ,text enclosed by equals is in bold 7bold74 - ,text enclosed by tildes is in antiqua 7antiqua74 - ,blank pages have been removed4 - ,obvious typographical errors have been silently corrected4 - ,odd-numbered page headings are entered at approximate locations as sidenotes1 except where repeated1 or duplicated in headings4 - ,errata from ,vol4 ,,ii4 applied4 - ,some headings and table of contents have been modified to be more consistent1 including removal of section list under ,chapter ,,ix as sections ,,ii-,,iv are in other chapters4