,transcriber's ,notes   ,table of       
,contents created by ,transcriber and   
placed in the ,public ,domain4  ,italic 
text is enclosed in underscores4  ,other
 notes will be found at the end of this 
e,book4     ,,the  ,,journal ,,of       
,,geology  ,,may-,,june1 #ahic4         
,,contents     ,on ,the ,typical        
,laurentian ,area of ,canada            
#cbe    ,melilite-,nepheline-,basalt and
 ,nepheline-,basanite from ,southern    
,texas                                  
#cdj    ,some ,dynamic ,phenomena ,shown
 by the ,baraboo ,quartzite ,ranges of  
,central ,wisconsin                     
#cdg    ,the ,chemical ,relation of     
,iron and ,manganese ,in ,sedimentary   
,rocks   #cef    ,some ,rivers of       
,connecticut                            
#cga    ,geological ,history of the     
,laurentian ,basin                      
#cid    ,editorials                     
#djh    ,reviews                        
#daj    ,analytical ,abstracts of       
,current ,literature                    

#dai    ,acknowledgments                
#dbc     ,,on ,,the ,,typical           
,,laurentian ,,area ,,of ,,canada4      
,the name ,laurentian was given by      
,logan in #ahed to the great series of  
rocks forming the ,laurentides or       
,laurentian ,mountains1 a district of   
mountainous country rising to the north 
of the ,river and ,gulf of ,st4         
,lawrence1 and extending in an unbroken 
stretch along the shore of the latter   
from ,quebec to ,labrador1 a distance of
 nine hundred miles4 ,this district1    
with its continuation to the west as far
 as ,lake ,huron1 being situated in the 
,province of ,quebec and the adjacent   
portion of the ,province of ,ontario1   
and forming part of the main ,protaxis  
of the continent1 is the 8,original     
,laurentian ,area0 of ,logan4 ,the      
,laurentian rocks are now known to      
extend far beyond the limits of this    
area to the west and north1             
constituting1 as they do1 by far the    
greater part of the ,protaxis1 and      

underlying 7with subordinate patches of 
,huronian7 an area of somewhat over two 
million square miles4#a ,the area above 
referred to is1 however1 the one which  
was first studied and described2 it is  
the 8,typical ,laurentian area10 and to 
it the observations in the present paper
 will be as far as possible confined4   
,a general exploration of the area in   
question1 and a more detailed study of a
 small part of it--the ,grenville       
,district--situated in the counties of  
,argenteuil and ,terrebonne in the      
,province of ,quebec1 was carried out by
 ,logan and his assistants in the early 
years of the ,canadian ,geological      
,survey4 ,an excellent rsum of the      
results of these studies is given in the
 8,geology of ,canada10 published in    
#ahfc1 which contains not only a good   
description of the general              
petrographical character and arrangement
 of the rocks which make up the area1   
but is accompanied by an atlas          
containing two maps illustrating this   

description1 one showing the general    
distribution of the ,laurentian in the  
eastern part of the ,dominion1 and the  
other its stratigraphical relations in  
the smaller area above referred to4  ,as
 a result of these studies1 ,logan      
announced his belief that the           
,laurentian ,system consisted of two    
great unconformable series of           
sedimentary rocks1 to which he gave the 
names ,upper and ,lower ,laurentian4    
,the latter he considered to be         
divisible into a lower and an upper     
portion1 which sub-divisions he regarded
 as probably conformable to one another4
 ,in the course of time these several   
series came to be known as the          
,anorthosite or ,norian ,series1 the    
,grenville ,series and the ,fundamental 
or ,ottawa ,gneiss4 ,logan's views may  
then be represented as follows3         
,anorthosite or ,norian ,series1        
,upper ,laurentian4   ,grenville        
,series1                ,upper portion  
,lower   ,fundamental or ,ottawa        

,gneiss1    ,lower portion  ,laurentian4
  ,subsequently1 in the southeastern    
corner of the ,province of ,ontario1 in 
the district lying to the north of the  
eastern end of ,lake ,ontario1 another  
series of rocks was discovered--the     
so-called ,hastings ,series4 ,logan     
supposed this to come in above the      
,grenville ,series1 while ,vennor1 who  
subsequently examined the district1     
believed it to be equivalent to the     
lower part of the ,grenville ,series    
already mentioned4  ,when these         
investigations were carried out1 the    
microscope had not as yet been seriously
 employed in petrographical work4 ,the  
precise composition of many of the rocks
 making up the several series was not   
recognized1 the effects produced by     
great dynamic action were not duly      
considered1 and the foliation possessed 
in a high degree by some and to a       
certain extent by almost all these rocks
 was considered1 in all cases1 to be a  
more or less obliterated survival of    

original bedding4 ,the detailed mapping 
in the field1 accompanied by            
microscopical work in the laboratory1 by
 which alone conclusive results can be  
obtained in working out the structure of
 complicated areas of crystalline       
schists1 was not carried out1 in fact in
 many districts the construction of     
detailed maps was at that time          
practically impossible4 ,it is not      
surprising therefore that1 although     
excellent in the main1 some of the      
results arrived at have since proved to 
be erroneous4  ,it is proposed1 in the  
present paper1 to place before the      
readers of this ,,journal in as brief a 
manner as possible1 a general account of
 the several series of rocks occurring  
in this area1 and to point out what1 in 
the opinion of the present writer1 seems
 to have been satisfactorily established
 concerning the stratigraphical position
 and mutual relations of these ancient  
rocks and what still remains to be      
determined by further study1 and in     

conclusion to give a short sketch of the
 evolution of this portion of the       
continent4  ,the ,fundamental           
,gneiss4--,exposed over very wide       
stretches of country in ,canada1 and    
making up in all probability by far the 
larger part of the ,archean ,protaxis1  
is the 8,fundamental ,gneiss10 sometimes
 called1 from its great development     
about the upper waters of the ,ottawa   
,river1 the 8,ottawa ,gneiss40 ,it is   
composed essentially of orthoclase      
gneiss1 usually reddish or greyish in   
color4 ,of this there are a number of   
varieties1 differing from one another in
 size of grain1 relative proportion of  
constituent minerals and in the         
distinctness of the foliation or        
banding4 ,it is sometimes rich in       
quartz1 while at other times this       
mineral is present in but very small    
amount4 ,it is usually poor in mica and 
bisilicates4 ,dark bands of amphibolite 
are not uncommon1 while basic hornblende
 or pyroxene gneisses occur in some     

places4 ,other schistose rocks are      
rarely found4 ,over great areas it is   
often nearly uniform in character and   
possesses a foliation which can only be 
recognized when exposures of            
considerable size are examined4 ,on this
 account it is often referred to as a   
granitoid gneiss1 a designation1        
however1 which by no means accurately   
describes it as a whole4 ,at a locality 
cited by ,sir ,william ,logan1 as one   
where it is typically developed1 namely1
 ,trembling ,mountain in the above      
mentioned ,grenville ,area1 it consists 
of a fine grained reddish orthoclase    
gneiss1 with distinct but not very      
decided foliation1 containing here and  
there bands of orthoclase gneiss of     
somewhat different character1 as well as
 bands or layers of a dark amphibolite4 
,how much of this ,fundamental ,gneiss  
really consists of eruptive material is 
not known4 ,the indistinct foliation1 in
 many cases at any rate1 is not a       
survival of original bedding1 but is    

clearly due to movements in a plastic   
mass4 ,it is often possible to recognize
 the existence of an indistinctly       
foliated gneiss intruded into more      
distinctly foliated gneiss4 ,the gneiss1
 in some cases1 shows excellently       
well-marked cataclastic structure1 while
 in other cases this is not distinct4   
,the evidence accumulated goes to show  
that the ,fundamental ,gneiss consists  
of a complicated series of rocks of     
unknown origin1 but comprising a        
considerable amount of material of      
intrusive character4  ,the ,grenville   
,series4--,in certain parts of the      
,laurentian area1 and notably in the    
,grenville district before mentioned1   
the ,laurentian has a decidedly         
different petrographical development4   
,orthoclase gneiss is still the         
predominating rock1 but it presents a   
much greater variety in mineralogical   
composition1 and is much more frequently
 well foliated1 often occurring in well 
defined bands or layers like the strata 

of later formations4  ,amphibolites are 
abundant1 also hornblende schists1 heavy
 beds of quartzite and numerous thick   
bands of crystalline limestone or       
marble1 all these rocks being           
interbanded or interstratified with one 
another4 ,in the vicinity of the        
limestones the variety in petrographical
 character is especially noticeable2    
garnets often occur abundantly in the   
gneiss1 the quartzite and the hornblende
 schist1 as well as in the limestone    
itself1 beds of pure garnet rock being  
found in places4 ,pyroxene1 wollastonite
 and other minerals are also abundant1  
while the presence of graphite          
disseminated through the limestones and 
their associated rocks1 often in such   
abundance as to give rise to deposits of
 economic value1 is of especial         
significance4 ,this mineral which is not
 found in the ,fundamental ,gneiss1     
occurs usually in little disseminated   
scales but occasionally in veins4 ,the  
limestones are thoroughly crystalline1  

generally somewhat coarse in grain and  
often nearly pure4 ,they usually1       
however1 contain grains of serpentine1  
pyroxene1 mica1 graphite or other       
minerals1 of which over fifty species   
have been noted4 ,they are often        
interstratified in thin bands with the  
gneiss1 in places are very impure1 and  
may be traced for great distances along 
the strike1 being apparently as         
continuous as any other element of the  
series4 ,this development of the        
,laurentian is known as the ,grenville  
,series1 and has been considered by all 
observers to be above and to rest upon  
the ,fundamental ,gneiss4 ,in it are    
found all the mineral deposits of       
economic value--apatite1 iron ore1      
asbestos1 etc41 which occur in the      
,laurentian4 ,the rocks of this series1 
though generally highly inclined1 over  
some large areas lie nearly horizontal  
or are inclined at very low angles1 but 
even in such cases they show evidence of
 having been subjected to great         

pressure1 resulting in some cases in the
 horizontal disruption of certain of the
 beds4  ,the areas occupied by the      
,grenville series although of very      
considerable extent1 being known to     
aggregate many thousand square miles1   
are probably small as compared with     
those underlain by the ,fundamental     
,gneiss4 ,the relative distribution of  
the two series has not been ascertained 
except in a general way in the more     
easily-accessible parts of the great    
,archean ,protaxis4 ,the ,grenville     
series is known to occupy a large part  
of its southern margin between the city 
of ,quebec and the ,georgian ,bay1 while
 the discovery of crystalline limestone 
in the gneiss elsewhere at several      
widely separated points1 as for instance
 on the ,hamilton ,river in ,labrador1  
in the southern part of ,baffin ,land   
and on the ,melville ,peninsula1 makes  
it probable that other considerable     
areas will1 with the progress of        
geological exploration1 be found in the 

far north4 ,over the greater part of the
 ,protaxis1 however1 the more monotonous
 development of the ,fundamental ,gneiss
 seems to prevail4  ,the question of the
 origin and mutual relations of the     
,fundamental ,gneiss and the ,grenville 
series is one about which1 though much  
has been written but little is known4   
,three views may be taken on the        
matter--  7#a7 ,the ,fundamental ,gneiss
 may be supposed to contain what remains
 of a primitive crust1 penetrated by    
great masses of igneous rock erupted    
through it--the whole having been       
subjected to repeated dynamic action4#b 
,the ,grenville ,series may be an upward
 continuation or development of the     
,fundamental ,gneiss under altered      
conditions1 marking in the history of   
the world the transition from those     
conditions under which a primitive crust
 formed to those in which sedimentation 
under the present normal conditions took
 place4 ,it would seem that if the earth
 originally had a crust on which the    

first sediments were deposited when the 
temperature became sufficiently low to  
permit water to condense1 that the said 
water1 at a very high temperature and   
under what are to us now inconceivable  
conditions but little removed from      
fusion1 might give rise to sediments not
 altogether similar to those formed by  
the ordinary processes of erosion at the
 present time4 ,also that1 under the    
unique conditions which must have       
prevailed at that early time1 in the    
formation of a crust solidification1    
precipitation and sedimentation might go
 on to a certain extent concomitantly1  
and thus no well-defined break could be 
detected1 or would in fact exist1       
between a primitive crust formed by     
solidification from a fused magma and   
the earliest aqueous sediments or       
deposits4 ,the ,fundamental ,gneiss and 
the ,grenville ,series might thus1 as   
,logan supposed1 form one practically   
continuous series and represent parts of
 the original crust1 with the first     

crystalline or clastic sediments        
deposited on it1 the whole penetrated by
 eruptive rocks and folded up and       
altered by repeated dynamic action at   
subsequent periods4  ,the general       
petrographical similarity of the two    
series1 taken in connection with the    
more varied nature of the ,grenville    
,series1 its frequent stratified        
character1 and the presence in it of    
limestones and graphite indicating an   
approach to modern conditions and the   
advent of life1 together with the       
difficulty of clearly separating the two
 series from one another and defining   
their respective limits1 lends support  
to this view4  7#b7 ,a second view is   
that the ,grenville ,series is distinct 
from the ,fundamental ,gneiss reposing  
on it unconformably and of much more    
recent age2 that it consists of a highly
 altered series of clastic origin--the  
,fundamental ,gneiss having possibly    
some such origin as that mentioned under
 the last heading1 or representing a    

much older series of still more highly  
altered sediments4 ,this is supported by
 the fact that some observers have      
thought they could in places trace out a
 line of contact between the two4 ,but  
in these cases it always becomes a      
matter of serious doubt whether what has
 been considered to represent the       
,fundamental ,gneiss is not really a    
mass of intrusive rock1 in which1 by    
pressure or motion1 a somewhat gneissic 
structure has been induced4 ,if the     
,fundamental ,gneiss1 moreover1 was ever
 an ordinary sediment1 it must have     
undergone a metamorphosis so profound   
that no trace of clastic origin remains1
 unless the generally indistinct        
foliation or banding of some portions of
 it be considered as such4 ,it must also
 be noted in this connection that1      
although the rocks of the ,grenville    
series are more frequently possessed of 
a decided foliation and are often       
banded1 bands of different composition  
alternating with one another as in      

ordinary sedimentary deposits1 and      
although in this series crystalline     
limestones and quartzites occur1 we have
 as yet no absolutely conclusive proof  
that even they are of sedimentary       
origin4 ,the series is thoroughly       
crystalline1 most of its members at     
least show the effect of great dynamic  
action1 and so far as the present writer
 is aware1 no undoubted conglomerate or 
finer grained rock showing distinct     
clastic structure has ever been found4  
,in view of this fact1--although the    
series is1 in all probability1 made up  
in part at least and perhaps wholly of  
sedimentary material1--the proposal to  
separate it from the rest of the        
,laurentian and class it as ,algonkian  
or ,huronian seems at least premature4  
7#c7 ,a third view which has been       
advanced is that the ,fundamental       
,gneiss is nothing more than a great    
mass of eruptive granite or granitic    
rock which has eaten upward1 and in     
places penetrated the ,grenville series1

 or perhaps absorbed it1 while the      
,grenville series itself represents a   
series of highly altered sediments of   
,laurentian1 ,huronian or subsequent    
age4 ,the enormous extent and world-wide
 distribution of the ,fundamental       
,gneiss forming as it does wherever the 
base of the geological column is exposed
 to view1 the foundation or floor on    
which all subsequent rocks are seen to  
rest1 is opposed to this view of its    
origin1 as is also its persistent       
gneissic or banded character1 although1 
as above mentioned1 much eruptive       
material is undoubtedly to be found in  
it4  ,which of these views is correct   
can be ascertained only as very careful 
and detailed mapping1 accompanied by    
accurate petrographical study1 is       
proceeded with4 ,in the present state of
 our knowledge additional argument and  
discussion will not help us toward the  
goal1 while hasty work and              
generalization serves but to retard the 
progress of our knowledge4  ,the        

,anorthosite ,series4--,associated with 
both the series of rocks just described 
there are1 as has been mentioned1 great 
eruptive masses of granite1 some of     
which have been folded in with the      
gneisses1 while others evidently erupted
 at a much later date1 show no trace of 
dynamic action4  ,in addition to these1 
basic eruptive rocks belonging to the   
gabbro family occur in certain          
districts1 sometimes in the form of     
comparatively insignificant masses1 but 
elsewhere underlying great tracts of    
country4 ,one on the upper waters of the
 ,saguenay has an area of no less than  
#e1hjj square miles4 ,these usually     
consist of a variety of gabbro in which 
the magnesia-iron constituents are      
present in very small amount1 being in  
many cases entirely wanting1 so that the
 rock consists practically of pure      
plagioclase feldspar4 ,these rocks were 
called anorthosites by ,hunt1 in the    
early reports of the ,canadian          
,geological ,survey1 on account of the  

great preponderance in them of          
8,anorthose10 a general name given many 
years ago by ,delesse to the triclinic  
feldspars1 as distinguished from        
8,orthose10 or orthoclase feldspar1 and 
thus equivalent to the term plagioclase 
now in general use1 but having no       
connection with anorthite1 a variety of 
plagioclase which is seldom present4    
,after a careful study of these rocks1  
both in the field and the laboratory1 it
 is believed that this name should be   
retained for this well-marked member of 
the gabbro family1 which1 though not a  
common rock elsewhere1 has an enormous  
distribution in the ,laurentian of      
,canada4  ,if an olivine gabbro be      
regarded as the central member1 so to   
speak1 of the gabbro family1 the        
replacement of the monoclinic by rhombic
 pyroxene will give rise to an olivine  
norite4 ,a gradual diminution in the    
amount of plagioclase will give rise to 
a peridotite or gabbro pyroxenite1 a    
diminution in the amount of pyroxene to 

a troktolite or plagioclase-olivine     
rock1 while a diminution in the amount  
of olivine and pyroxene will give rise  
to an anorthosite1 which variety forms  
the greater part of the intrusive masses
 in question4 ,the gradual passage of   
one variety into another can be         
distinctly traced in many localities in 
the anorthosite masses4 ,these          
anorthosites are in some places massive1
 but very frequently show a distinct    
foliation1 often very perfect4 ,in some 
places they occur interbanded with the  
gneiss and crystalline limestone1 while 
elsewhere they cut directly across the  
strike of these rocks4 ,the interbanded 
anorthosite1 together with the gneiss   
and limestone associated with it1 was   
supposed by ,logan to form a distinct   
sedimentary series1 to which the name   
8,upper ,laurentian10 or 8,norian10 was 
given1 because the discovery that       
elsewhere the anorthosite runs across   
the strike of the gneiss was supposed to
 indicate that this series covered up   

and unconformably overlay the ,grenville
 series1 the igneous and intrusive      
character of the anorthosite not being  
recognized on account of its frequently 
foliated structure4 ,it is now known    
that these anorthosites do not          
constitute an independent formation1 but
 are igneous rocks which occur1 cutting 
both the ,grenville series and the      
,fundamental gneiss4 ,they have1        
however1 in many cases been intruded    
before the cessation of the great       
dynamic movements to which the          
,laurentian was subjected in            
pre-,cambrian times1 and thus frequently
 taking a line of least resistance and  
having been intruded between the bands  
or strata of the ,grenville series1 have
 had a foliation induced in them        
parallel to that of the gneiss1 while in
 other cases where they are more or less
 massive1 they cut across the strike of 
the latter4  ,in many cases the         
anorthosites which exhibit a perfect    
foliation may be traced step by step    

into the massive variety1 the gradual   
development of a foliated structure in  
the rock being accompanied by a         
progressive granulation of the          
constituents1 most beautifully seen     
under the microscope4 ,the change1      
however1 differs from any hitherto      
described in that it is purely          
mechanical4 ,there are no lines of      
shearing with accompanying chemical     
changes1 but a breaking up of the       
constituents throughout the whole mass1 
though in some places this has          
progressed much further than in others1 
unaccompanied by any alteration of      
augite or hypersthene to hornblende1 or 
of plagioclase to saussurite1 these     
minerals1 though prone to such          
alteration under pressure remaining     
quite unaltered1 suffering merely a     
granulation with the arrangement of the 
granulated material in parallel strings4
 ,this process can be observed in all   
its stages1 and there is reason to      
believe that it has been brought about  

by pressure acting on the rocks when    
they were deeply buried and very hot4#c 
,the anorthosite areas1 of which there  
are about a dozen of great extent with  
many of smaller size1 are distributed   
along the south and southeastern edge of
 the main ,archean ,protaxis from       
,labrador to ,lake ,champlain1 occupying
 in this way a position similar to that 
of volcanoes along the edge of our      
present continents4 ,curiously enough   
precisely similar occurrences of this   
anorthosite have been found in          
connection with similar gneissic rocks1 
supposed to be of ,archean age1 in      
,russia1 ,norway and ,egypt4 ,these     
anorthosite rocks being intrusive1 may  
be left out of consideration in         
endeavoring to work out the succession  
of the ,archean in this great area4     
,the whole ,laurentian system1 including
 the anorthosites1 is in many places cut
 by numerous dykes of large size1 which 
can often be traced for great distances4
 ,these are of several kinds1 the       

principal series consisting of a        
beautiful fresh diabase often holding   
quartz in considerable amount in        
micro-pegmatitic intergrowths with      
plagioclase4 ,other sets of dykes and   
eruptive masses consisting of augite and
 mica syenites1 quartz-porphyries and   
other rocks are also known to occur but 
have not as yet been carefully studied4 
,the ,hastings ,series4--,the           
stratigraphical relations of the        
,hastings series have not as yet been   
satisfactorily determined4 ,the rocks   
constituting the series differ widely in
 petrographical character from those of 
the ,fundamental ,gneiss and the        
,grenville series1 both of which are    
supposed to occur in its immediate      
neighborhood4 ,the series consists      
largely of calc-schists1 mica-schists1  
dolomites1 slates and conglomerates1    
thus containing much material of        
undoubtedly clastic origin4 ,it has     
moreover a very local development1 being
 confined1 so far as at present known1  

to one small corner of the area1 as has 
been mentioned4 ,it was by ,logan       
supposed to come in above the ,grenville
 series1 while ,vennor who subsequently 
examined the district1 believed it to be
 equivalent to the lower part of this   
series4 ,that we have in the ,hastings  
series a comparatively unaltered part of
 the ,grenville series1 made up largely 
of rocks whose origin is easily         
recognized1 would be a most important   
fact if established1 and would1 of      
course1 afford a key to the whole       
question of the origin of the latter4   
,this is a conclusion1 however1 which   
cannot be accepted until supported by   
very clear and decisive evidence1       
especially as the stratigraphy of the   
,hastings district is very complicated1 
the several series represented in it    
being much folded and penetrated by     
great masses of eruptive rocks4 ,the    
whole district has also been subject to 
great dynamic action1 some of the       
pebbles in the conglomerates of the     

,hastings series being distorted in a   
most remarkable manner4 ,this series may
 prove to be merely an outlying area of 
,huronian rocks folded in with the      
,laurentian1 and until the district has 
been studied in detail its              
stratigraphical position must remain a  
matter of conjecture4  ,leaving the     
,hastings series out of consideration   
therefore1 we have in this ,original and
 ,typical ,laurentian area two          
developments of the ,laurentian1        
generally considered as constituting two
 series1 namely the    ,grenville or    
,upper series1   ,fundamental1 ,ottawa1 
or ,lower ,gneiss4  ,the ,evolution of  
the ,area4--,in endeavoring to outline  
the main events in the evolution of this
 area it will be necessary to extend the
 limits of our observation somewhat and 
seek for evidence bearing on the        
question in other parts of the          
,protaxis1 where we meet with           
developments of ,huronian and various   
earlier ,paleozoic strata not found in  

the typical area itself4  ,from the     
highly contorted condition of the       
,laurentian rocks of this area as well  
as from the abundant evidences of       
dynamic action which they present both  
in the field and under the microscope1  
it is evident that they have been       
subjected to great orographic forces1   
which in very early times threw them up 
into mountain ranges1 probably of great 
height4 ,some of the associated eruptive
 rocks were intruded before these       
movements began1 or while they were in  
progress and have accordingly been      
influenced by them1 while others1 having
 been intruded later1 have not been     
affected4  ,how high these mountains    
rose cannot of course be determined4    
,bell states that some of the mountains 
on the ,labrador coast now rise to a    
height of from #e1jjj to #f1jjj feet1   
while ,lieber has estimated that on the 
coast of ,northern ,labrador they rise  
to a height of from #f1jjj to #aj1jjj   
feet4 ,along the southern part of the   

,protaxis1 where the country is much    
lower1 notwithstanding the enormous     
subaerial denudation and glaciation     
which the area has repeatedly undergone1
 there are many points still rising from
 #b1ejj to #c1ejj feet above sea level1 
while ,logan estimated that the average 
elevation is from #a1ejj to #a1fjj feet4
 ,in the ,adirondacks1 which are but an 
outlying portion of this area1 there are
 elevations of over #e1djj feet4 ,the   
high elevations attained by these rocks 
in portions of the ,protaxis in the     
north may1 of course1 be due to         
differential elevation1 but immediately 
along the southern edge of the area     
there can have been but little          
differential change of level as compared
 with the flat-lying ,potsdam strata    
which border it and lie but little above
 the present sea level4 ,further        
evidence of the original height or      
continued uprising of the area is       
afforded by the fact that all the       
material of which the ,north ,american  

continent was built up 7with the        
possible exception of some of the       
limestones7 was derived originally from 
the ,archean ,protaxis of the continent1
 a considerable proportion of this at   
least coming from the main ,protaxis of 
which this typical ,laurentian area     
forms a part4 ,we must conclude         
therefore that in early ,cambrian or    
pre-,cambrian times1 in portions of the 
,protaxis at least1 the ,laurentian     
mountains rose several hundred and      
possibly in places several thousand feet
 above the sea level4  ,the intrusion of
 the granites and anorthosites as well  
as the folding of the whole system of   
rocks took place before ,upper ,cambrian
 times4 ,the whole series was moreover  
without doubt at that time in the       
8metamorphic0 condition in which we now 
find it1 for along the margin of the    
area the ,potsdam sandstone rests in    
flat undisturbed beds on the deeply     
eroded remnants of these old mountains1 
its basal beds often consisting of a    

conglomerate with pebbles of the        
underlying gneissic rocks4 ,these       
,cambrian strata cover up the gneisses1 
granites and anorthosites alike and are 
evidently of much more recent age1 being
 separated from the ,laurentian by the  
long interval occupied in the upheaval  
and erosion of the ,laurentian area4    
,how long before ,upper ,cambrian times 
this folding and erosion took place     
cannot be determined from a study of    
this area1 but further west along the   
edge of the ,protaxis in the ,lake      
,superior district we find that the     
,keweenawan1 ,nipigon and ,animikie     
,series also repose in flat undisturbed 
beds on the eroded remnants of a series 
of crystalline rocks which have the     
petrographical character of the         
,fundamental ,gneiss4 ,this makes it at 
least very probable that in this eastern
 area also the erosion took place in    
pre-,cambrian times4  ,it is a very     
remarkable fact that the roche moutonn  
character possessed by these eroded     

,laurentian rocks and which is usually  
attributed to the glaciation which they 
underwent in ,pleistocene times1 was    
really impressed upon them in the first 
instance in these pre-,cambrian times1  
for all along the edge of the nucleus   
from ,lake ,superior to the ,saguenay1  
the ,paleozoic strata1 often in little  
patches1 can be seen to overlie and     
cover up a mammillated and roche moutonn
 surface showing no traces of decay and 
similar to that exposed over the        
uncovered part of the area4 ,the        
conclusion therefore seems inevitable   
that not only were these ,laurentian    
rocks sharply folded and subjected to   
enormous erosion1 but that they had     
given to them in pre-,cambrian times    
their peculiar hummocky contours so     
suggestive of ice action4#d ,the        
pre-,paleozoic surface of the           
,fundamental ,gneiss of ,scotland1 as   
,sir ,archibald ,geikie has shown1 also 
presents the same hummocky character4#e 
,on this surface the ,upper ,huronian1  

,cambrian1 and later ,paleozoic rocks   
were deposited4  ,to what extent the    
seas of ,cambrian1 ,silurian and        
,devonian times passed over this area   
cannot be determined with certainty4 ,a 
great series of rocks referred to by    
,dr4 ,g4 ,m4 ,dawson as probably of     
,lower ,cambrian age and analogous in   
character to the ,keweenawan and        
,animikie series occur overlying the    
,laurentian in many parts of the        
,protaxis1 not only along its margin1   
but as outliers at many places in the   
interior4 ,it occurs extensively        
developed about the ,arctic ,ocean and  
about ,hudson's ,bay1 and a large area  
of rocks referred to the same age also  
occur near the height of land about     
,lake ,mistassini4 8,throughout the     
whole of the vast northern part of the  
continent this characteristic ,cambrian 
formation1 composed largely of volcanic 
rocks1 apparently occupies the same     
unconformable position with regard to   
the underlying ,laurentian and ,huronian

 systems4 ,its present remnants serve to
 indicate the position of some of the   
earliest geological basins1 which from  
the attitude of the rocks appear to have
 undergone comparatively little         
disturbance4 ,its extent entitles it to 
be recognized as one of the most        
important geological features of ,north 
,america40#f ,it would1 therefore1 seem 
that in ,cambrian times a not           
inconsiderable part of the ,archean     
,nucleus was under water4 ,outliers of  
,cambro-,silurian age are also found at 
several points lying well within the    
margin of the ,nucleus1 as for instance 
in the ,ottawa ,river about ,pembroke at
 a distance of fifty miles1 and at ,lake
 ,st4 ,john at the head of the ,saguenay
 ,river at a distance of one hundred and
 thirty miles from its present limit4   
,there is reason to believe that a      
similar outlier exists in the interior  
of the northern part of the ,peninsula  
of ,labrador1 so that the ,lower        
,paleozoic sea must also have covered   

considerable areas in the eastern half  
of the ,protaxis1 where now nothing but 
,laurentian is to be seen4 ,in that     
portion of the ,protaxis lying to the   
west of ,hudson's ,bay strata of        
,cambro-,silurian and ,devonian age     
extend up from the basin of ,hudson's   
,bay on the east and from the great     
plains on the west far over the         
,laurentian ,plateau and probably1      
according to ,dr4 ,dawson1 originally   
inosculated4 ,strata of ,upper ,silurian
 and ,devonian age are not known to     
exist in the eastern half of the        
,protaxis1 of which the typical         
,laurentian area forms part1 with the   
exception of a small outlier of ,niagara
 age on ,lake ,temiscamangue at the head
 waters of the ,ottawa--neither do any  
other deposits of later age occur with  
the exception of the ,glacial ,drift4   
,what evidence there is1 therefore1     
would rather indicate that the area1    
during late ,paleozoic1 ,mesozoic and   
earlier ,tertiary times1 was out of     

water4 ,if so1 it must have undergone   
during this great lapse of ages a       
process of deep seated decay and        
denudation1 culminating in the extensive
 glaciation to which it was subjected in
 ,pleistocene times4  ,during this      
latter period the whole area was exposed
 to ice action1 with the exception of   
the highest part of the ,nucleus--the   
mountains of the ,labrador coast--which1
 except toward the base1 are still      
8softened1 eroded and deeply decayed40#g
 ,this extensive denudation served to   
remove all but mere remnants of any     
,paleozoic strata originally deposited  
on the ,archean of this area1 while the 
deep decay of the ,archean rocks        
themselves would account for the immense
 numbers of gneiss bowlders in the      
drift1 which in all probability are but 
smoothed cores of 8bowlders of          
decomposition40 ,that an immense amount 
of material was removed from the surface
 of the area during the glacial age is  
shown by the immense quantities of      

,archean material which occurs scattered
 over the surface of the ,nucleus       
itself1 as well as in the drift to the  
south4 ,the glaciation1 with the        
depression and uplift which succeeded   
it1 was the last episode in the         
evolution of this 8original0 ,laurentian
 area and one which impressed upon it   
its present surface characters and type 
of landscape4  ,it is now an immense    
uneven plateau1 comparatively slightly  
accentuated except along the ,labrador  
coast4 ,the surface is covered with     
glaciated hills and bosses of rock with 
rounded1 mammilated1 flowing contours   
interspersed with drift covered flats   
and studded with thousands upon         
thousands of lakes great and small4 ,a  
country which in the far north is often 
bleak and desolate1 but to the south1   
where it is covered with luxuriant      
forest1 is often of great beauty1       
especially when clothed with the        
brilliant foliage of autumn4 ,even now1 
however1 it is passing into a further   

stage of its history1 the smooth or     
polished glaciated surfaces are becoming
 roughened by decay1 the softer gneissic
 and limestone strata are again         
commencing to crumble into soil1 and a  
new epoch has been inaugurated in which 
the marks of the ice age are being      
gradually effaced4                      
,,frank ,d4 ,,adams4  ,,mcgill          
,,university4   ,,footnotes      #a     
,accepting the distribution of the      
,laurentian in the far north1           
given by ,dr4 ,g4 ,m4 ,dawson1 as       
correct1 the area is #b1jja1bej         
square miles4 ,this does not include the
 outlying and separated         areas   
occurring in ,newfoundland1 ,new ,york  
,state and ,michigan4      #b ,see also1
 ,the ,geological ,history of the ,north
 ,atlantic1 by ,sir         ,william    
,dawson1 ,presidential ,address1 ,b4 ,a4
 ,a4 ,s41 #ahhf4      #c ,see ,,frank   
,d4 ,,adams--8,ueber das ,norian oder   
,ober-,laurentian         von ,canada10 
,neues ,jahrbuch fr ,mineralogie1 etc41 

,beilageband         ,,viii41 #ahic4    
#d ,a4 ,c4 ,,lawson4--8,notes on the    
,pre-,palaeozoic surface of the         
,archean ,terranes of ,canada40         
,bulletin of the ,geological ,society   
of ,america4 ,vol4 #a1 #ahij4      #e   
8,a ,fragment of ,primeval ,europe40    
,nature1 ,august #bf1 #ahhh4      #f ,g4
 ,m4 ,,dawson4--8,notes to accompany a  
geological map of the         northern  
portion of the ,dominion of ,canada40   
,report of the         ,geological      
,survey of ,canada1 #ahhf4 p4 #i1 ,r4   
#g ,,robert ,,bell4--8,observations on  
the ,geology etc41 of the               
,labrador ,coast1 ,hudson's ,strait and 
,bay40 ,report of the                   
,geological ,survey of ,canada4         
#ahhb-c-d1 p4 #ad1 ,,dd4                
,,melilite-,,nepheline-,,basalt ,,and   
,,nepheline-,,basanite ,,from ,,southern
 ,,texas4   ,these basaltic rocks were  
collected by ,professor ,dumble and ,mr4
 ,taff1 in ,uvalde ,county1 southern    
,texas4 ,on the geological map of the   

,united ,states1 compiled by ,c4 ,h4    
,hitchcock1 #ahhf1 there are two of the 
localities marked near the boundary of  
the ,cretaceous and earlier ,tertiary   
formation1 between #ii and #ajj         
longitude1 and on the #bith degree of   
latitude4 ,according to the statement of
 ,professor ,dumble1 one part of the    
rocks appears in dikes in the upper     
portion of the lower ,cretaceous        
formation1 while the other forms hills  
and buttes4 ,upon microscopical         
examination it is evident that the      
specimens collected belong to two       
different groups of rocks4 ,the         
microscope shows that those occurring in
 dikes consist of typical               
melilite-bearing nepheline-basalt1 while
 those making up hills and buttes are   
nepheline-basanites tending toward      
phonolites in composition4  ,the        
melilite-nepheline-basalts have a       
typical basaltic appearance4 ,in a dense
 black groundmass1 the only phenocrysts 
seen by the naked eye are numerous      

olivines4 ,under the microscope there   
appear in addition to the olivine the   
following minerals3 augite1 nepheline1  
melilite1 magnetite and perovskite4 ,as 
to the proportion of nepheline and      
melilite1 it can be said1 that in nearly
 all the specimens examined1 the two    
minerals are found in about the same    
amount4 ,for this reason these rocks can
 be placed under the head of            
nepheline-basalt as well as under that  
of melilite-basalt1 or they may be      
called melilite-nepheline-basalt4 ,only 
one of the specimens is entirely free   
from melilite4 ,feldspar is wholly      
wanting4 ,all of the specimens are in a 
very fresh condition1 and even the      
melilite shows only slight indications  
of decomposition4 ,the specimen free    
from melilite corresponds in structure  
and composition with the other          
specimens1 except for the absence of    
melilite and perovskite1 and so they may
 be described together4  ,all the rocks 
are porphyritic1 since they bear large  

phenocrysts of olivine4 ,under the      
microscope the olivine is colorless and 
transparent1 and only shows indications 
of serpentinization along the edges and 
fissures4 ,it contains rounded          
inclusions of glass1 abundant in some   
sections1 besides octahedrons of        
magnetite1 and others that are          
transparent with a brownish violet      
color4 ,whether the latter are a mineral
 of the spinel-group or belong to       
perovskite1 with which they accord in   
color1 could not be decided4  ,augite   
occurs in only one generation2          
phenocrysts of augite are wanting4 ,in  
the rather coarse-grained groundmass1 it
 becomes the most abundant constituent4 
,the mineral shows a grayish-brown      
color1 common to basaltic augite1       
sometimes with a tint of violet4 ,it    
generally forms well-shaped crystals1   
rarely irregular grains1 and bears      
inclusions of magnetite and glass4      
,melilite occurs in the groundmass in   
large and well-shaped crystals1 its     

dimensions never becoming as small as   
those of many of the augite crystals4   
,they may be designated as              
micro-porphyritical phenocrysts4 ,cross 
sections parallel to 7#jja7 reach a     
diameter of #j4e mm4 ,the shape of the  
melilite is the common one1 tabular     
parallel to 7#jja74 ,the diameter of the
 tables generally exceeds their         
thickness from four to six times4       
,sections parallel to the prism-zone1   
therefore1 are lath-shaped and the      
vertical axis lies perpendicular to     
their length2 the axis of greatest      
elasticity coincides with the vertical  
axis4 ,between crossed nicols these     
sections show the particular blue       
interference colors characteristic of   
melilite and zoisite4 ,sections         
perpendicular to the prism-zone are     
eight-sided by reason of the planes     
7#aaj7 and 7#ajj71 but frequently the   
outlines are rounded4 ,in some of the   
sections examined the melilite incloses 
minute opaque grains arranged zonally1  

which present very sharply the prismatic
 outlines of their host4 ,besides the   
two prismatic faces above mentioned1    
there is also a ditetragonal prism1 the 
angle of which upon the adjoining faces 
of 7#aaj7 and 7#ajj7 was found to be    
nearly equal1 #bj-bb4 ,according to this
 measurement the prism must have        
approximately the position of 7#idj72   
the angle of the latter upon 7#aaj7 is  
#ba #b1 the angle upon 7#ajj7  #bc #eh4 
,a particular phenomenon in the growth  
of the melilite is the fact that the    
base does not generally present an even 
plane1 but shows a conical depression4  
,the shape of the lath-shaped sections  
then resembles the profile of a         
biconcave lens4 ,sections parallel to   
the base are isotropic between crossed  
nicols and show1 when they are not too  
thin1 an indistinct dark cross in       
convergent light4 ,the cleavage parallel
 to 7#jja71 the cross-fibration of the  
lath-shaped sections and the occurrence 
of the spear-shaped and peg-shaped      

inclusions arranged parallel to the c   
axis 7the so-called ,pflockstruktur7 are
 very distinct4 ,inclusions of pyroxene1
 magnetite and glass are common2 as     
already mentioned1 these inclusions are 
generally arranged in zones4 ,in        
sections parallel to 7#jja7 they fill   
the central parts of their host1 and    
often make up two or three concentric   
zones4 ,these sections closely resemble 
leucite because of their rounded shape1 
the arrangement of the inclusions and   
the lack of double refraction4 ,melilite
 becomes nearly colorless and           
transparent1 but in comparing it with   
the white1 colorless nepheline1 it shows
 a feeble yellow tint4 ,decomposition   
has taken place to only a small extent2 
it begins along the cross-fibration1 and
 greenish-yellow alteration-products    
result1 the fibres of which are         
perpendicular to the length of the      
lath-shaped sections4  ,nepheline is    
always fresh1 colorless and transparent2
 it rarely exhibits a regular shape1 but

 generally forms an aggregate of        
irregular grains1 cementing the other   
components2 it is evidently the latest  
formed mineral in the rock4  ,there is  
abundant magnetite besides perovskite1  
the common associate of melilite1 which 
occurs in small octahedrons and         
irregular grains4 ,the perovskite       
becomes transparent with a              
brownish-violet color1 and shows in some
 sections a feeble1 abnormal double     
refraction4 ,there appears to be no     
isotropic base in the normal rock1 but  
if any is present1 it must be in a very 
small amount4 ,there are coarser grained
 spots in the rock1 which are rich in a 
partly chloritized base1 and in which   
nepheline occurs in well-shaped         
crystals4  ,the second group of rocks1  
as already mentioned1 falls under the   
head of nepheline-basanite poor in      
olivine4 ,and since the specimens bear  
sanidine phenocrysts beside plagioclase1
 it forms a transition to phonolite4    
,the rock-specimens have a more         

andesitic than basaltic appearance4     
,numerous phenocrysts of hornblende and 
augite are imbedded in the dense        
bluish-gray groundmass4 ,the next most  
abundant mineral is nepheline in the    
form of phenocrysts1 in part well-shaped
 crystals1 in part rounded1 the largest 
of which are #j4e cm4 in diameter4 ,the 
nepheline differs from the feldspar in  
having a grayish color and greasy       
lustre4 ,phenocrysts of feldspar and    
crystals of olivine are scarce4 ,beside 
these components1 the rocks contain     
apatite1 some titanite and iron ores4   
,under the microscope olivine is seen to
 be scarce4 ,it is fresh and shows the  
normal properties4 ,it contains minute  
octahedrons of picotite and in some     
sections abundant inclusions of a liquid
 with moving bubbles4  ,the amphibole   
mineral is a typical basaltic           
hornblende4 ,it becomes transparent with
 a dark reddish-brown color and exhibits
 a strong pleochroism according to the  
following scheme3  a1 brownish yellow1 b

 and c dark reddish brown4 ,absorption1 
c  b  a4  ,the angle of extinction was  
examined in sections cut approximately  
parallel to the clinopinacoid 7#jaj7 and
 was determined to be very small4 ,this 
fact and the dark reddish-brown color   
are in all probability due to a high    
amount of ,fe,o4 ,the dependence of the 
angle of extinction upon the amount of  
,fe,o in minerals of the amphibole group
 has been recently established by       
,schneider and ,belowsky4 ,the basaltic 
hornblende shows the well-known dark    
borders produced by reabsorption by the 
magma in an early stage of              
consolidation4 ,in many cases nothing of
 the original mineral is preserved2 the 
whole hornblende is replaced by a fine  
grained aggregate of pyroxene and       
magnetite1 presenting clearly the       
outlines of the absorbed mineral4  ,the 
group of pyroxenic minerals is          
represented by two monoclinic augites4  
,one of them exhibits a violet-gray     
color in thin section and belongs to the

 basaltic augites2 the other one becomes
 transparent with a dark green color4   
,both form numerous phenocrysts1 but the
 first occurs somewhat more frequently4 
,they occur as single crystals and are  
also grown together in a zonal manner1  
the green one always forming the center1
 the gray one the outer parts of the    
crystals4 ,hence the gray augite is the 
younger4 ,the pyroxene in the groundmass
 shows the same color and properties4   
,the pleochroism of the two minerals is 
as follows3    ,gray augite4            
,green augite4   a ,brownish-yellow     
,light yellowish-green   b              
,dark gray-green   c  ,violet-gray      
,dark green4  ,the angle of extinction1 
c3 c1 is large and1 as may be seen in   
the zonal crystals1 it is somewhat      
larger in the gray pyroxene than in the 
green4 ,the extinction in sections cut  
approximately parallel to 7#jaj7 has    
been observed to be about #dg degrees   
7gray augite7 and #da degrees 7green    
augite74 ,the two pyroxenes show in     

addition to the cleavage parallel to    
7#aaj7 another but less distinct one    
parallel to 7#jaj74 ,inclusions of      
magnetite1 apatite and glass are common4
  ,phenocrysts of feldspar are scarce4  
,in part they show the polysynthetic    
twinning lamination of plagioclase2 in  
part the latter is wanting and one of   
the latter feldspars1 which was isolated
 and examined for specific gravity and  
optical properties1 was found to be     
sanidine4 ,phenocrysts of nepheline are 
more frequent than those of feldspar4   
,the mineral appears partly in the form 
of short-prismatic crystals1 partly in  
rounded grains4 ,it presents distinct   
cleavage1 parallel to 7#ajaj7 and to    
7#jjja71 and the usually observed       
optical properties4 ,isolated grains are
 decomposed by hydrochloric acid with   
the separation of gelatinous silica2 the
 resulting solution when evaporated     
gives numerous cubes of ,na,cl4         
,inclusions are scarce2 there are fluid 
cavities with moving bubbles1 generally 

arranged in rows1 besides some pyroxene 
crystals4  ,apatite forms short and     
stout crystals always filled with       
inclusions of liquids4 ,the opaque ore  
grains1 judging by their ready          
solubility1 belong to magnetite4 ,the   
groundmass of these rocks consists      
essentially of pyroxene in well-shaped  
prisms1 lath-shaped feldspar1 without   
twinning lamination or in single twins  
according to the ,carlsbad law and      
nepheline4 ,the feldspar of the         
groundmass in all probability is mostly 
sanidine4 ,nepheline is abundant and    
occurs in well-shaped crystals4 ,small  
patches of a colorless base occur       
between the crystalline components4     
,the structure of the rocks is          
hypocrystalline-porphyritic on account  
of the occurrence of an isotropic base  
and the repetition of the               
crystallization of pyroxene1 nepheline  
and feldspar4 ,although the specimens by
 their whole habit and structure belong 
under the head of nepheline-basanite    

poor in olivine1 the presence of        
sanidine as phenocrysts causes them to  
form a transition to the group of       
phonolites4 ,unfortunately1 analyses of 
these rocks have not yet been made4  ,a 
microscopical examination of the        
basaltic rock from ,pilot ,knob1 near   
,austin1 ,travis ,county1 was made for  
the purpose of comparison with the rocks
 from southern ,texas just described4   
,the rock was found to be a             
nepheline-basalt porphyritic with       
numerous phenocrysts of olivine4 ,the   
fine grained groundmass consists        
essentially of augite-crystals cemented 
by non-individualized nepheline in very 
small amount4                      ,a4  
,,osann4     ,,some ,,dynamic           
,,phenomena ,,shown ,,by ,,the ,,baraboo
 ,,quartzite ,,ranges ,,of ,,central    
,,wisconsin4   ,the quartzite ranges of 
,baraboo extend east and west for about 
thirty miles1 one lying north1 and the  
other1 the main range1 lying south of   
the ,city of ,baraboo4 ,the geology of  

this district is admirably given by the 
late ,professor ,irving4#h ,not only is 
the general geology clearly described1  
but remarkably accurate descriptions are
 given of the character of the          
quartzite1 and the phenomena shown by   
it1 considering the fact that the report
 was written nearly twenty years since4 
,the unconformity existing between the  
quartzite and the ,cambrian was later   
more fully described4#i ,the induration 
of the ,baraboo quartzite has been      
explained as due to the enlargement of  
the original quartz grains2 and to the  
deposition of independent interstitial  
quartz4#aj ,the present note is based   
upon recent observations on the ,east   
,bluff at ,devil's ,lake and on the     
exposures at the ,upper ,narrows of the 
,baraboo ,river4  ,the section across   
the ranges1 as given by ,irving1 is     
shown by ,fig4 #a4 ,the two ranges      
together1 as thus represented1 are less 
than the north half of a great          
anticline1 the south side of the south  

range being near its crown4 ,this       
structure involves a very great         
thickness of quartzite1 and was offered 
with reservation by ,professor ,irving4 
,he says3 8,the hypothesis is not       
altogether satisfactory4 ,the entire    
disappearance of the other side of the  
great arch1 as well as the peculiar ways
 in which the ranges come together at   
their extremities are difficult to      
explain by it4 ,it may be said in this  
connection that the dip observations    
toward the west are not so satisfactory 
or numerous as they might be40 ,the     
question naturally arises whether or not
 the great width of the ranges in the   
central part of the area may not be     
partly explained by monoclinal faulting1
 and thus reduce the supposed thickness 
of the beds4  ,illustration3 ,,fig4     
#a4--;,ideal ,sketch1 showing structure 
and amount of erosion of the ,baraboo   
,ranges4  ,after ,irving4  ,scale       
natural1 #ab1jjj feet to the inch4  ,the
 layers of quartzite are ordinarily very

 heavy1 but the changing character of   
the original sediment is such as to make
 it easy to follow the layers4 ,some    
beds were composed of fine grains of    
quartz1 mingled with clayey material1   
others of coarse grains with little     
clayey material1 and others of pebbles  
so large as to pass into an unmistakable
 conglomerate4 ,the pebbles of the      
conglomerate are mainly white quartz and
 red jasper4 ,it is thus easy to        
discriminate the bedding of the series  
from the heavy jointing which occurs1   
cutting the bedding in various          
directions1 and from a secondary        
cleavage and foliation which occurs in  
certain localities4  ,from the general  
work of many geologists on dynamic      
action in folding1 it is to be expected 
that the amount of movement necessary   
for accommodation between beds1 and     
consequently the dynamic metamorphism   
resulting from shearing1 would be less  
near the crown of the anticline than on 
the leg of the fold4 ,that is1 dynamic  

metamorphism ought not to be so         
extensive in the south range as in the  
north range4 ,the facts described by    
,irving1#aa and those noted by me1 fully
 agree with this anticipation4 ,the     
central parts of the heavy1 little      
inclined beds of the south range are    
largely indurated by simple enlargement4
 ,the pressure has not been sufficient  
to obliterate the cores1 but has        
apparently granulated the exterior of   
some of the larger fragments1 as in hand
 specimens the exteriors of the large   
blue quartz grains are white4 ,very     
generally the grains show slight wavy   
extinction4 ,a few of them are          
distinctly cracked4 ,the crevices thus  
formed and those in the interstices have
 been filled in large part by           
infiltrated silica1 but their positions 
are plainly indicated by difference in  
extinction1 by bubbles1 by iron oxide1  
or by secondary mica which has taken    
advantage of the minute crevices4       
,however1 as described by ,irving1      

between the heavy beds of quartzites are
 often layers1 cut by a diagonal        
cleavage which dies out in passing into 
the thick beds4 ,the layers showing     
cleavage sometimes pass into those      
showing the beginning of foliation1 the 
rock then nearing a schist4 ,in the     
centers of the schist zones1 the        
schistosity approaches parallelism with 
the bedding1 and in passing outward     
curves from this direction until it     
crosses the bedding at an angle1 at the 
same time becoming less marked and      
grading into ordinary cleavage1 which   
dies out in the quartzite4 ,upon the    
opposite side the transition is of the  
same character1 but the curve is in the 
opposite direction4  ,irving apparently 
regarded these shear zones as originally
 beds of a different character from the 
adjacent quartzite1 and his conclusion  
is fully borne out by the thin sections4
 ,the microscope shows that the grains  
of quartz are of small size1 and        
separated to a greater or a less extent 

by interstitial clayey material4        
,because of this partial separation of  
the grains of quartz1 they have not been
 granulated to the extent that one would
 expect from the schistosity of the     
rock1 most of the original cores being  
plainly visible4 ,they1 however1 often  
show wavy extinction and even cracks1   
but not to a greater degree than the    
grains in the massive quartzite2 for in 
the latter the full stress of the       
pressure has been borne by the grains in
 full touch1 not separated by a plastic 
matrix1 as are the grains of quartz in  
the argillaceous layers4 ,in the matrix 
of the schist are numerous small flakes 
of muscovite1 arranged with their longer
 axes in a common direction1 much finely
 crystalline quartz1 and a good deal of 
iron oxide4  ,it is concluded that the  
clayey character of the beds1 and1      
consequently1 the greater ease of       
movement within them1 has located the   
slipping-planes and shear-zones1        
necessary in order to accommodate the   

beds to their new positions4 ,on the    
south range1 near ,devil's ,lake1 these 
shear-zones are generally not more than 
six or eight inches wide4 ,they may be  
well seen just back of the ,cliff       
,house1 and on the ,northwestern        
,railway1 about one-half mile south of  
this house4 ,all of these shear-zones   
are parallel with the bedding1 and      
illustrate the possibility1 so far as ,i
 know first mentioned by ,h4 ,l4 ,smyth1
 that a crystalline schist1 with        
schistosity parallel to bedding1 may be 
produced by shearing along the          
bedding-planes4  ,on the railroad track1
 near the locality where these          
shear-zones may be seen1 is also an     
almost vertical shear-zone1 two to four 
feet wide4 ,it therefore cuts almost    
directly across the beds of quartzite1  
which here incline to the south about   
twelve or thirteen degrees4 ,throughout 
this band1 the quartzite is broken into 
angular trapezoidal fragments1 the      
longer directions of which are vertical1

 and which may be picked out with the   
hammer4 ,in certain parts of the zone   
well-defined gruss or friction clay     
produced by the grinding of the         
fragments against one another1 has been 
produced4 ,this is clearly a plane of   
faulting4 ,how much the throw of this   
fault is it is not easy to say1 as the  
heavy beds of quartzite are so similar  
that it is impossible to certainly      
identify them4 ,at this place there is1 
however1 a change in the character of   
the quartzite1 layers of light color    
being overlain by other beds1 which are 
more heavily stained with iron oxide4   
,this same succession is seen on both   
sides of the fault1 and if beds of like 
character correspond1 the amount of the 
throw is twenty to thirty feet1 and the 
south side has dropped relative to the  
north side4 ,in other words1 the        
faulting is in the right direction to   
reduce the theoretical thickness of the 
sediments as given by ,irving4 ,the     
district has not been closely examined  

for other faults1 but the existence of  
one fault1 even of a minor character1   
suggests that a careful study of the    
whole area with reference to faulting   
should be made1 in order to determine   
what deductions may possibly be made    
from ,irving's estimate of the probable 
thickness of the quartzite4  ,at the    
upper narrows of the ,baraboo1 near     
,ablemans1 we are on the north leg of   
the anticline4 ,the dip is throughout   
from seventy to ninety to the north1 and
 in some places the layers are slightly 
overturned4 ,the slipping along the     
bedding has here been much greater4     
,while in this area there are heavy beds
 of quartzite which have not suffered   
great interior movement1 other beds have
 been sheared throughout1 being         
transformed macroscopically into a      
quartz-schist1 but the foliation is     
strongly developed4 ,in other places1 as
 described by ,irving1#ab where the rock
 is a purer quartzite1 for a distance of
 #bjj feet or more across the strike1   

the rocks have been shattered through   
and through1 and re-cemented by vein    
quartz4  ,for the most part the rock is 
merely fractured1 the quartz fragments  
roughly fitting one another1 but there  
are all gradations from this phase to a 
belt about ten feet wide of true        
friction conglomerate1 the fragments    
having been ground against one another  
until they have become well-rounded 7a  
,reibungs breccia74 ,between the        
boulders of this zone is a matrix1      
composed mainly of smaller quartzite    
fragments4 ,the whole has been          
re-cemented1 so that now the mass is    
completely vitreous4 ,this belt of      
friction conglomerate at first might not
 be discriminated from the ,potsdam     
conglomerate1 immediately adjacent1 but 
a closer study shows how radically      
different they are4 ,in one the         
cementing material is vein-quartz2 in   
the other the sandstone has been feebly 
cemented by quartz enlargement4  ,a     
movement later than the one which       

produced the cemented fractured rocks   
and breccia has broken broad zones of   
the massive beds of quartzite into      
lozenge-shaped blocks1 the longer axes  
of which are parallel to the bedding and
 movement4 ,these later-formed blocks   
have not been re-cemented by secondary  
quartz1 and the cracks are taken        
advantage of in quarrying1 the fragments
 being easily picked apart4 ,thus the   
rock has been affected by at least two  
dynamic movements1 separated by a       
considerable interval of time4  ,the    
shear-zones1 often several feet in      
width1 particularly affect the more     
finely-laminated layers1 which are lean 
in quartz1 while the relief in the more 
massive layers has resulted in complex  
fracturing4 ,in the first phase of      
production of the schist1 the irregular 
fractures pass into rather regular      
fractures1 cutting the beds nearly at   
right angles4 ,as the action becomes    
more intense in the more argillaceous   
beds1 the angle of fracture1 or         

cleavage1 as it may now fairly be       
called1 becomes more acute1 and in the  
most intense phase this cleaved rock    
passes into a well-developed schist1 the
 foliation of which is parallel to the  
bedding4 ,the phenomena of shearing are 
here therefore very similar to those at 
,devil's ,lake1 except that the process 
has gone farther4  ,when studied in thin
 section1 the massive beds of quartzite 
show more decided effects of dynamic    
action than at ,devil's ,lake4 ,however1
 the major portions of the grains of    
quartz have distinct cores which are    
often beautifully enlarged4 ,in some    
cases nearly every grain has thus grown1
 perfectly indurating the rock4 ,but1   
also1 nearly every grain of quartz has a
 wavy extinction1 and many of them have 
been fractured1 as mentioned of a few of
 the quartz grains of the quartzites of 
the south range4 ,in one case the       
pressure has been so great as to produce
 rather numerous roughly parallel lines 
of fracture4 ,it is thus seen that the  

dynamic effects are not confined to the 
schist zones1 but are also prominent    
within the heavy beds of quartzite4     
,this was to be expected2 for while the 
major part of the accommodation         
necessary to bend the rock mass as a    
whole took place along the shear zones1 
the accommodation required to bend each 
of the rigid heavy beds of quartzite    
must have taken place within each layer4
 ,to the consequent intense pressure and
 the rubbing of the grains over one     
another1 are wholly attributed their    
wavy extinction and fractures4  ,in the 
schists of the shear zones1 as at the   
south range1 the thin sections show that
 the original quartz grains were small2 
interstitial material was present1 and  
mica has developed more largely than in 
the quartzite4 ,however1 in the most    
crystalline phases1 the fragmental cores
 of the quartz grains and their frequent
 enlargements are plainly seen4 ,thus   
the shearing has not been sufficient to 
produce a completely crystalline schist1

 although this would not be             
macroscopically discovered1 unless it   
were suspected because the rock is not  
thinly foliated4  ,as the dip of the    
quartzite is so steep at this locality1 
it is difficult to say how far the      
shifting of the beds over one another   
lessens the apparent thickness4 ,the    
shear zones as well as the friction     
conglomerates appear to be parallel to  
the bedding4 ,if they are exactly so1   
this shearing action would necessitate  
an estimate of the original thickness   
greater than now shown1 since the shear 
zones probably have less width at the   
present time than the beds from which   
they were originally produced4  ,cutting
 the bedding are heavy joints inclined  
to the north at an angle of #bj to #cj4 
,if slipping had occurred along these in
 the right direction1 this might cause a
 small thickness of beds to have a great
 apparent thickness4 ,however1 the      
schists above described weather out on  
the face of the cliffs1 and are         

therefore marked by recessions in the   
walls4 ,if slipping parallel to the     
jointing had occurred since the schists 
were formed1 these depressions ought not
 to match on opposite sides of the      
joints2 but1 on the contrary1 they      
continue unbroken from foot to top1 and 
probably the joints were formed         
simultaneously with or later than the   
belts of schist4 ,consequently1 at the  
upper narrows of the ,baraboo no        
evidence was found of faulting which    
could reduce the estimated thickness of 
the quartzite as given by ,irving4  ,as 
,irving clearly saw1 bearing strongly in
 favor of the theory of a great fold1 is
 the increasing steeper dip of the      
layers in passing north4 ,the phenomena 
of movement and metamorphism            
corresponding so exactly to those       
required by a simple fold1 the question 
may be asked if these are not evidence  
of some weight in favor of the general  
correctness of ,irving's conclusion as  
to the structure4 ,had monoclinal       

faulting extensively occurred1 it would 
not have been necessary to have had so  
great a readjustment of the beds as has 
been shown to occur by the schists1     
cleavage1 and the exceedingly intricate 
macro-fracturing and micro-fracturing of
 the rock beds and their constituent    
particles4  ,in addition to the         
phenomena described by ,irving1 in      
summary1 the ,baraboo quartzite ranges  
show results of dynamic metamorphism as 
follows3 ,a fine example of the         
,reibungs ,breccia may be seen4 ,a fault
 zone of limited throw exists4 ,all     
phases are exhibited1 between a massive 
quartzite1 showing macroscopically      
little evidence of interior movement    
through a rock exhibiting in turn       
fracture and cleavage1 to a rock which  
macroscopically is apparently a         
crystalline schist4 ,the foliation of   
the schists is parallel to the original 
stratification1 being consequent upon   
the movements of the beds over one      
another1 readjustments occurring mainly 

in the softer layers4 ,in thin sections 
the schists still give clear evidence of
 their fragmental origin1 but also show 
the mechanical effects of interior      
movement4 ,these same effects are       
apparent within the heavy beds of       
quartzite1 some readjustment of the     
particles to their new positions being  
here also necessary4 ,there is no       
evidence that the semi-crystalline      
character of the schist and quartzite   
are due to high heat4 ,nowhere are the  
particles fused4 ,so far as they are    
destroyed it is by fracture1 and the    
rock is again healed by cementation4    
,the rock1 in its most altered condition
 being a semi-crystalline schist1 and in
 other parts showing less change1 can be
 connected with its original state4 ,had
 the folding been more intense1 it is   
reasonable to suppose that the entire   
rock would have been transformed into a 
completely crystalline quartz-schist1   
showing no evidence of clastic origin1  
and possibly the foliation throughout   

would have corresponded to the original 
bedding4                      ,c4 ,r4   
,,van ,,hise4   ,,footnotes      #h ,the
 ,baraboo ,quartzite ,ranges1 by ,r4 ,d4
 ,irving4 ,in ,vol4 ,,ii1         ,geol4
 of ,wis41 pp4 #ejd-eai4      #i ,the   
,classification of the ,early ,cambrian 
and pre-,cambrian         ,formations1  
,r4 ,d4 ,irving4 ,in #gth ,annual ,rep41
 ,u4 ,s4 ,g4 ,s41 pp4         #djc-djh4 
#aj ,enlargement of ,quartz ,fragments  
and ,genesis of ,quartzites1 by         
,r4 ,d4 ,irving and ,c4 ,r4 ,van ,hise4 
,in ,bull4 #h1 ,u4 ,s4 ,g4 ,s41 pp4     
#cc1 #cd4     #aa ,the ,baraboo         
,quartzite ,ranges1 by ,r4 ,d4 ,irving4 
,in ,vol4 ,,ii1         ,geol4 of ,wis41
 pp4 #eaj1 #eaf4     #ab ,the ,baraboo  
,quartzite ,ranges1 by ,r4 ,d4 ,irving4 
,in ,vol4 ,,ii41         ,geol4 of      
,wis41 p4 #eaf4     ,,the ,,chemical    
,,relation ,,of ,,iron ,,and ,,manganese
 ,,in ,,sedimentary ,,rocks4   ,iron and
 manganese are frequent constituents of 
sedimentary rocks1 in some places       

occurring finely disseminated through   
sandstones and shales1 or forming a part
 of limestones1 in other places forming 
the mass of the deposit in which they   
occur4 ,they are both derived primarily 
from similar1 and often from the same   
sources1 and are in many respects alike 
in their chemical behavior in nature4   
,for these reasons it is to be expected 
that they would frequently1 if not      
generally1 be deposited in intimate     
association4 ,such is found to be the   
case1 and iron and manganese are often  
closely associated in the same deposits4
 ,very often1 however1 iron and         
manganese deposits occur close together1
 but distinctly separated1 while        
sometimes extensive deposits of iron1   
and less commonly of manganese1 occur   
with little or almost no association    
with each other4  ,it is the object of  
the present paper to discuss the        
agencies which are instrumental in      
causing these substances to be deposited
 sometimes together and at other times  

separately4 ,the subject is of interest 
as showing how slight differences in the
 chemical behavior of their salts may   
cause the almost complete separation of 
metals once intimately associated4      
,,the ,,connection ,,of ,,iron ,,and    
,,manganese ,,in ,,nature4  ,a few words
 concerning the relation of manganese to
 iron in nature will perhaps make the   
following discussion clearer4 ,one of   
the most common modes of occurrence of  
manganese is with iron1 though extensive
 deposits containing manganese more or  
less free from iron often occur4 ,when  
associated with iron1 manganese occurs  
with it in various ways4 ,sometimes the 
two are intimately mixed1 so that they  
have the appearance of a homogeneous    
mass1 resembling iron ore when iron is  
in the preponderance and manganese ore  
when manganese predominates4 ,in such   
cases there appears to be no tendency to
 combine in one fixed proportion1       
though1 as iron is a much more abundant 
substance than manganese1 the mixture   

most commonly contains an excess of     
iron1 and exists in the form of a       
manganiferous iron ore4 ,the manganese1 
when not intimately mixed with the iron1
 may occur in it in pockets or as       
scattered nodules and concretions4 ,such
 occurrences as those described are     
frequent in the ,lake ,superior iron    
region1 the ,appalachian ,valley of the 
eastern states1 in ,nova ,scotia1       
,arkansas1 ,colorado1 ,new ,mexico and  
innumerable other places4 ,in ,virginia 
very common occurrences are alternating 
layers of iron and manganese ore4 ,the  
iron in such cases is generally in the  
larger quantities and the more          
continuous deposits2 while the manganese
 is often represented by thin lenticular
 layers or by bands of nodules4  ,from  
such cases1 where iron predominates1    
there are all gradations in admixture1  
up to the rarer cases where manganese   
predominates4 ,frequently a given       
geologic horizon is characterized by    
both iron and manganese1 though in one  

case it may contain only iron1 in       
another only manganese1 and in still    
another iron and manganese mixed in     
various proportions4 ,a remarkable case 
of this is seen in the iron and         
manganese horizons immediately above1 or
 a short distance above1 the ,paleozoic 
quartzite1 on the east side of the      
,appalachian ,valley1 especially in the 
,valley of ,virginia4#ac ,here deposits 
of iron ore1 of manganese ore1 and of   
both ores mixed1 are found at various   
points along the same geologic horizons4
 ,similar alternations also occur in the
 ,lower ,silurian novaculites of the    
,ouachita ,mountains of ,arkansas1#ad in
 ,cebolla ,valley1 in ,gunnison county1 
,colorado1#ae and in many other places4 
,in many cases certain horizons are     
characterized over large areas by iron  
alone1 and but little manganese1 as is  
well seen in the ,clinton formation and 
in the ,tertiary iron-ore horizons of   
,arkansas and ,texas2 while1 on the     
other hand1 some areas of certain       

horizons contain considerable quantities
 of manganese and very little iron1 as  
is seen in parts of the ,marine         
limestone in ,new ,brunswick and ,nova  
,scotia1 and also in parts of the       
metamorphosed ,cretaceous shales of     
,california4   ,,the ,,source ,,of      
,,iron ,,and ,,manganese ,,in           
,,sedimentary ,,rocks4  ,the iron and   
manganese contained in sedimentary      
strata may be considered as derived     
primarily from the decay of pre-existing
 rocks4 ,some of the later sedimentary  
rocks may have derived a part or all of 
their iron from older sedimentary rocks1
 which1 in turn1 had derived their iron 
and manganese from still older rocks4   
,in this way the iron and manganese in a
 given geologic horizon may have formed 
a part of various older horizons before 
they reached their present resting      
place1 but1 in every case1 their primary
 source can be traced back to the       
original materials from which           
sedimentary rocks were first formed4 ,in

 certain cases the sea water has        
supplied a certain amount of iron and   
manganese to sedimentary rocks1 but in  
such cases the sea water acts only as a 
carrier of these materials from the land
 areas or from submarine sources to the 
strata then forming4   ,,the            
,,transportation ,,of ,,iron ,,and      
,,manganese ,,in ,,nature4  ,the process
 that goes on in this interchange of    
iron and manganese from older to younger
 rocks is as follows3  7#a7 ,the        
conversion1 by surface agencies1 of the 
minerals containing iron and manganese  
into forms that can be taken into       
solution by surface waters4  7#b7 ,the  
solution of the iron and manganese in   
surface waters1 acidulated with organic 
and sometimes inorganic acids1 and their
 transportation in this form from the   
areas of older rocks to areas over which
 younger rocks are being deposited4     
7#c7 ,finally1 the precipitation in one 
or more of several ways of the iron and 
manganese contained in solution4  ,the  

iron and manganese thus chemically      
precipitated may be deposited either    
with mechanical sediments1 such as sand1
 clay etc41 or without them4 ,if the    
deposition of mechanical sediments is   
largely in excess of the precipitation  
of iron and manganese1 the final        
products will be beds of ferruginous    
shale1 sandstone1 etc41 common in many  
geologic horizons4 ,if the precipitation
 of iron and manganese is in excess of  
the deposition of mechanical sediments1 
the resulting products are deposits of  
more or less pure iron and manganese    
ore4 ,between these two extremes there  
are all gradations in the admixture of  
the iron and manganese with mechanical  
sediments4  ,frequently the iron and    
manganese which were originally finely  
disseminated through shale1 sandstone1  
etc41 are subsequently concentrated into
 bodies of comparatively pure ore1 and  
very commonly this concentration takes  
place by a process of re-solution of the
 iron and manganese and re-deposition by

 replacement with limestone1 or1 more   
rarely1 with some other material4 ,the  
limestone or other material which thus  
acts as a precipitant is often in the   
same series of strata from which the    
iron and manganese were removed1 and    
thus these two substances1 which were   
once in a finely disseminated condition1
 may be converted into deposits of      
comparatively pure ore and yet remain in
 the same general series of strata in   
which they were originally deposited4 ,a
 remarkable case of this is seen in the 
iron deposits of the ,penokee series in 
,michigan and ,wisconsin1#af to be      
mentioned again on page #cgj4 ,it has   
also been suggested by ,h4 ,d4          
,rogers#ag that certain siderite        
deposits in the ,coal ,measures were    
formed by the conversion of finely      
disseminated sesquioxide of iron into   
carbonate of iron by organic matter1 and
 the subsequent segregation of the      
carbonate as now found in layers and    
nodules4  ,the surface waters that carry

 the iron and manganese to the strata   
being deposited at a given time are     
sometimes derived from areas in which   
iron predominates1 sometimes from areas 
in which iron and manganese are both    
abundant1 and sometimes1 though rarely1 
on account of the scarcity of such      
regions1 from areas in which manganese  
largely predominates over iron4 ,if iron
 and manganese were always precipitated 
from these waters in similar chemical   
forms and under the same conditions1 it 
would be expected that the strata       
deriving their iron and manganese from  
surface waters would contain those      
substances in the same relative         
proportions as they had existed in the  
rocks from which they were derived1 and 
that they would be in an intimately     
mixed condition4 ,such is doubtless     
often the case1 or at least             
approximately so2 but it is also often  
the case that iron and manganese occur  
in separate deposits1 yet in close      
proximity to each other and often       

alternating along the same horizon4     
,besides this1 the two substances       
frequently form parts of the same       
deposit and yet are distinctly separate 
from each other4 ,in such cases the     
question arises as to why the iron and  
manganese are not intimately mixed in   
the form of a manganiferous iron ore1 as
 would be expected if they had been     
precipitated together4 ,moreover1       
deposits sometimes occur which are      
composed largely of manganese ore1 with 
little or almost no iron1 and when the  
source of the manganese is looked for1  
we often find that the rocks which      
probably supplied it contained both     
manganese and iron1 and that the iron   
was present in a much larger proportion 
as regards the manganese than in the new
 deposit4 ,here again the question      
arises as to why the iron and manganese 
are not in the same relative proportions
 in the new deposit as they were in the 
rocks from which they were derived4     
,four principal causes suggest          

themselves in explanation of this       
separation3  7#a7 ,it might be supposed 
that the deposits containing mostly iron
 and those containing mostly manganese  
received these constituents from waters 
derived from different sources1 and     
carrying iron and manganese only in the 
proportions in which they deposited     
them4 ,under some conditions this       
explanation might suffice1 but in many  
cases1 such as when iron and manganese  
alternate along the same geologic       
horizon1 and yet in close proximity with
 each other1 the explanation is entirely
 inadequate1 for the deposits are too   
close to each other to have been formed 
from different supplies of surface      
waters4  7#b7 ,it might be supposed that
 the iron or the manganese had been     
leached out of a deposit of the mixed   
ores1 leaving one free from the other   
and depositing the dissolved ore        
somewhere else4 ,this explanation1      
except in special cases1 also appears   
inadequate1 because the reagents in     

surface waters1 which dissolve iron and 
manganese1 seem to affect both about    
equally1 so that if one were dissolved1 
the other should be taken up in the same
 way4 ,doubtless small differences could
 be found in the behavior of the organic
 and inorganic compounds in surface     
waters towards iron and manganese       
minerals1 but they would be small as    
compared with the more active reactions 
which go on4  7#c7 ,it might be supposed
 that a separation could be produced by 
secondary concentration such as         
segregation1 replacement1 etc4 ,this has
 doubtless sometimes been the case1 but 
where the concentrating action is not   
assisted by a difference in the chemical
 behavior of the two substances1 the    
separation would only be on a small     
scale4 ,even in the case of             
concentration by replacement of         
limestone1 if iron and manganese both   
acted in the same way during the        
replacement1 it would be expected to    
find them deposited in an intimate      

mixture4 ,though this secondary         
concentration1 therefore1 unassisted by 
other agencies1 would not produce all   
the results found in nature1 yet1 when  
it is thus assisted1 it often plays an  
important part4  7#d7 ,the fourth1 and  
what seems the most important1 factor in
 the separation of iron and manganese1  
is that1 though very often they are     
precipitated in the same form from the  
same solution1 yet sometimes they are   
precipitated in different forms2 and    
even when precipitated in the same form1
 the precipitation of one sometimes     
requires different conditions from the  
precipitation of the other4 ,this fact  
will explain the alternate association  
and separation of iron and manganese1   
not only when no secondary concentration
 has gone on1 but also in cases where   
such concentration has taken place1 such
 as in the replacement of limestone1    
etc4  ,it will now be attempted to show 
how the various degrees of association  
and separation of iron and manganese    

found in nature may be produced by      
different conditions during deposition4 
,,the ,,forms ,,of ,,iron ,,and         
,,manganese ,,deposited ,,at ,,ordinary 
,,temperatures4  ,the mineralogical     
forms in which iron and manganese are   
deposited from solution in nature at    
ordinary temperatures depend on the     
conditions of air and water1 whether of 
an oxidizing or a reducing nature1 and  
on the character of the associated      
organic and inorganic matter either in  
solution or on the floor of the sea1    
lagoon or bog in which the deposition   
occurs4#ah ,there are four principal    
methods by which iron and manganese are 
precipitated in nature from surface     
waters3  7#a7 ,by oxidation1 as in the  
case of the precipitation of hydrous    
oxides and in the precipitation of the  
carbonate by the partial oxidation of   
more complex organic salts4#ai  7#b7 ,by
 reduction1 as in the precipitation of  
sulphide of iron by the reduction of    
sulphate of iron4  7#c7 ,by gaseous or  

soluble precipitants1 as in the         
precipitation of sulphide of iron by the
 action of sulphuretted hydrogen or a   
soluble sulphide on a soluble salt of   
iron1 and as in other cases to be       
mentioned later4  7#d7 ,by replacement  
of carbonate of lime or some other      
substance4 ,different forms are         
precipitated by these different methods4
  ,iron at ordinary temperatures is     
usually deposited from solution as the  
hydrous sesquioxide1 the carbonate1 the 
sulphide or the hydrous silicate of iron
 and potash known as glauconite4        
,manganese under similar conditions is  
deposited as the hydrous oxide#bj or as 
the carbonate1 and possibly sometimes1  
though very rarely1 as sulphide4  ,when 
solutions of organic or inorganic salts 
of iron and manganese are freely exposed
 to the action of air1 as in shallow or 
rapidly moving streams1 or in lakes and 
some bogs1 they are quickly oxidized and
 both may be deposited as more or less  
hydrous oxides4 ,in many bogs1 however1 

the metals may be precipitated as       
hydrous oxide on the surface where      
oxidizing agencies predominate1 but when
 these oxides sink and come into contact
 with decaying organic matter1 free from
 the active oxidizing influences of the 
air1 they may be reduced to carbonates4 
,the carbonates of iron and manganese   
may be precipitated when the solutions  
containing them are protected from      
oxidation by a reducing agent1 such as  
decaying organic matter1 or by being far
 removed from the air4 ,carbonate of    
manganese1 however1 is a much more      
stable compound than carbonate of iron1 
and the oxidizing conditions are often  
sufficiently strong to cause the        
deposition of iron as hydrous           
sesquioxide and not strong enough to    
change the manganese from its carbonate 
form4 ,it is not uncommon1 therefore1 to
 have iron deposited in one place as    
hydrous sesquioxide1 and manganese      
carried further on and deposited as     
carbonate1 or even under special        

conditions deposited as carbonate with  
the hydrous sesquioxide of iron4        
,fresenius#ba has shown that the warm   
springs of ,wiesbaden1 which contain    
iron and manganese among their other    
mineral constituents1 deposit iron in   
the form of hydrous sesquioxide1 while  
manganese is carried on further in      
solution and deposited as carbonate4 ,in
 this behavior1 therefore1 we have the  
first striking difference in the        
deposition of iron and manganese1 and it
 will be further discussed later on4    
,the sulphides of iron and manganese    
differ very much in their nature and    
mode of occurrence4 ,iron is frequently 
deposited as sulphide1 but manganese    
rarely occurs in that form1 and when it 
does it is always in very small         
quantities4 ,iron forms several         
sulphides in nature3 pyrite 7,fe,s71    
marcasite 7,fe,s71#bb pyrrhotite        
7,fe,s71 troilite 7,fe,s7 and numerous  
other more complex compounds unnecessary
 to enumerate here4 ,pyrite is the      

commonest form of iron sulphide1 and    
occurs in rocks of all ages1 from       
,archean to ,recent4 ,it is formed in   
nature by the action of soluble         
sulphides or sulphuretted hydrogen on   
soluble salts of iron1 and also by the  
reduction of sulphate of iron by organic
 matter or other reducing agents4       
,manganese forms two#bc sulphides1      
alabandite 7,mn,s7 and hauerite 7,mn,s74
 ,both minerals are very rare1 and so   
unstable that they rapidly oxidize on   
exposure4 ,alabandite is the less rare  
form1 and usually occurs as a           
subordinate constituent of certain      
metalliferous veins or allied deposits4 
,though the sulphides of manganese are  
easily oxidized1 they are not so        
unstable that1 had they ever been formed
 in considerable quantities in          
sedimentary deposits1 they would1 even  
at considerable depths1 have left no    
trace of their former presence4         
,moreover1 the sulphide of manganese1 as
 produced artificially1#bd is soluble in

 certain organic acids1 notably acetic1 
and1 as the conditions for the          
deposition of sulphides of metals in    
sedimentary deposits generally require  
the presence of organic matter1 it is   
not improbable that some of the acids   
given off by such matter would be       
capable of dissolving sulphide of       
manganese4 ,here1 then1 is one reason   
why manganese might not be deposited as 
sulphide under some conditions which    
would cause the precipitation of        
sulphide of iron4 ,moreover1 the        
artificial formation of sulphide of     
manganese 7alabandite7 in the laboratory
 is brought about most easily at high   
temperatures4 ,it has also been noted   
that when manganese1 in the form of the 
alloys spiegeleisen and ferro-manganese1
 is added to molten steel1 it bodily    
removes a part of the sulphur2 and it is
 thought by some metallurgists1 that    
sulphide of manganese is formed and     
carried into the slag4  ,these and other
 indications of the more easy transition

 of manganese into the form of sulphide 
at high rather than at low temperatures 
afford another cause which might prevent
 sulphide of manganese from being formed
 in sedimentary deposits1 for such      
deposits are usually laid down at       
ordinary temperatures4 ,on the other    
hand1 they also afford a cause which    
might lead to the deposition of the     
sulphide of manganese in certain        
metalliferous veins and other deposits1 
where the temperature at the time of    
deposition may have been high4  ,in many
 of the silver and lead deposits of the 
,rocky ,mountains manganese oxides occur
 with the superficial oxidation products
 of the sulphides of other metals1 and  
it has often been suggested that the    
manganese also was originally in the    
form of sulphide4 ,this may be true in  
some cases1 for alabandite has been     
found in a few metalliferous deposits in
 ,colorado1 ,mexico1 ,germany1 ,peru and
 elsewhere1 but in most cases1 at least 
in the ,rocky ,mountains1 when the level

 is reached at which the oxidized forms 
of lead1 zinc1 iron and other metals    
pass into sulphides1 the manganese      
passes into carbonate or silicate1 and  
remains in one or both of those forms to
 all depths that have been reached4  ,in
 the deposition of iron and manganese as
 sulphide1 therefore1 there is a most   
marked difference of behavior1 and here 
again is a good cause for the separation
 of the two substances in sedimentary   
rocks1 as will be more fully explained  
below4  ,iron is often deposited in     
sedimentary formations as the hydrous   
silicate of iron and potash known as    
glauconite1 and composes the mass of the
 large greensand beds common in         
,cretaceous and ,tertiary strata2 but   
manganese is not found in an exactly    
similar condition4#be ,here again1      
therefore1 is an important difference in
 the modes of deposition of iron and    
manganese1 which also will be mentioned 
again4  ,it will thus be seen that while
 some of the forms in which iron and    

manganese are deposited are the same1   
others differ very widely1 and even     
similar forms are often deposited under 
different conditions4 ,it is doubtless  
to these various forms and conditions of
 deposition that the alternate          
association and separation of iron and  
manganese in nature are due4   ,,causes 
,,of ,,the ,,association ,,of ,,iron    
,,and ,,manganese4  ,the very frequent  
intimate association of iron and        
manganese in sedimentary rocks is what  
would be expected from a deposition as  
oxide or carbonate in basins such as    
coastal lagoons or bogs1 where the      
waters moved very slowly1 or not at all1
 for under such conditions1 they are    
often deposited together4#bf ,moreover1 
it is a well-known fact that isomorphous
 substances have a strong tendency to   
combine in a homogeneous mass1 and to   
crystallize together in different       
proportions4 ,carbonate of iron and of  
manganese are isomorphous with each     
other1 and this is hence a possible     

cause of the frequent intimacy of their 
association1 such as is seen in almost  
all manganiferous spathic iron ores1    
whether these ores are formed by direct 
precipitation or by replacement of      
carbonate of lime4 ,the oxidation of    
such a mixture would give the common    
form of an intimately combined iron and 
manganese ore4  ,since there is usually 
more iron than manganese in the rocks   
from which both metals were originally  
derived1 the surface waters draining    
from areas of such rocks usually contain
 the metals in a similar proportion4    
,hence1 in cases where the deposition of
 the carbonates of both occurs at the   
same spot1 the isomorphous carbonates   
derived from the solutions have a larger
 percentage of carbonate of iron than of
 carbonate of manganese1 and the        
resulting oxides contain the two metals 
in the same proportion1 thus giving rise
 to the common low-manganese iron ores4 
,the hydrous oxides of iron and         
manganese1 however1 are not             

isomorphous1#bg and1 therefore1 when    
they are precipitated together1 as in   
bog-deposits1 the association is often  
much less intimate than in the cases    
just mentioned1 and is simply due to the
 fact that1 under certain conditions1   
the oxides of both metals are           
precipitated in the same place4         
,,causes ,,of ,,the ,,separation ,,of   
,,iron ,,and ,,manganese4  ,when iron   
and manganese ores occur in more or less
 separate deposits1 it becomes necessary
 to suppose the action of influences    
different from those which cause the    
deposition of both together1 and such   
influences are to be found in the       
different modes of precipitation1 under 
certain conditions1 of the two metals4  
,it has been shown by ,fresenius#bh that
 certain warm springs1 on reaching the  
surface1 first deposit hydrous          
sesquioxide of iron1 and farther on     
carbonate of manganese4 ,this not only  
points to the well-known fact that      
carbonate of iron is more easily        

oxidized than carbonate of manganese1   
but it also leads to the belief that the
 bicarbonate or other salt of iron in   
the water is more easily oxidized than  
the manganese salt4  ,an action somewhat
 similar to that described by ,fresenius
 readily explains the occurrence of     
manganese sometimes in entirely separate
 deposits1 sometimes in distinct but    
closely alternating deposits4#bi ,under 
certain conditions1 if the waters from  
which the precipitation took place were 
moving1 the iron and manganese1 owing to
 the difference in oxidability1 as      
stated above1 would be laid down in     
different places1 resulting in the      
formation of deposits of iron ore free  
from manganese1 and manganese ore free  
from iron in different positions along  
the plane of the same geologic horizon4 
,such occurrences are often seen in the 
iron regions of the ,appalachian        
,valley1 where there are often found1 in
 different places along the same belt1  
deposits of iron ore and deposits of    

manganese ore in positions similar with 
relation to the enclosing rocks4  ,these
 conditions of moving water might also  
cause the occurrence of the two ores in 
interstratified layers1 as is sometimes 
the case4 ,such a condition would result
 if iron were deposited in a certain    
place at one time1 and if1 later1 on    
account of some increased facility for  
oxidation1 iron was deposited before it 
reached that place1 and the manganese1  
being less easily precipitated1 were    
carried on and laid down upon the first 
deposit of iron4  ,suppose the          
metalliferous solutions to be confined  
in a shallow basin1 or1 at least1 to    
pass through it so slowly that they     
become thoroughly oxidized4 ,under such 
conditions the deposition of iron and   
manganese would go on continuously1 and 
so nearly on the same spot that a       
comparatively homogeneous manganiferous 
iron ore would be formed4 ,if the supply
 of metalliferous solutions were not    
continuous1 but were intermittent1 as is

 sometimes the case in local basins1    
such as coastal lagoons1 which are often
 dependent for their supply of water on 
the changes of season and the sudden    
fluctuations of weather1 then           
interstratified layers of iron and      
manganese ore might be produced4 ,the   
iron1 becoming oxidized on the surface1 
sinks to the bottom1 possibly in some   
cases to be converted there to the      
simple carbonate by organic matter4     
,further oxidation precipitates hydrous 
oxide or carbonate of manganese on top  
of the iron4 ,a renewed supply of       
surface waters brings more solutions of 
iron and manganese1 or else the         
evaporation of the water in the closed  
basin concentrates the materials which  
have not yet been precipitated4 ,in     
either case there is a further alternate
 deposition of the two ores4#cj         
,another process of separation of iron  
and manganese in nature might take place
 by the formation of sulphide of iron4  
,it has already been shown that iron is 

sometimes deposited as sulphide and     
later oxidized in the same manner as the
 carbonate4 ,manganese1 on the other    
hand1 is rarely found as sulphide1 and  
there is reason to think that the       
sulphide never represented the original 
form of any large sedimentary deposits  
of manganese ore 7see pages #cfd to     
#cfe74 ,it seems probable1 therefore1   
that from a solution of iron and        
manganese in surface waters the iron    
might1 where the conditions are         
favorable1 be precipitated as sulphide  
7,fe,s7 and the manganese might be      
carried on in solution to be deposited  
somewhere else as oxide or carbonate4   
,subsequently the oxidation of the ores 
would give rise to oxide of iron from   
the sulphide and oxide of manganese from
 the carbonate2 and the two ores1 though
 occurring at the same horizon1 would be
 separated by a greater or less         
distance4  ,after the deposition of the 
sulphide of iron1 the conditions might  
change and permit the deposition1 in the

 same place1 of the carbonates of iron  
and manganese together4 ,this is an easy
 case to imagine1 and where such a      
deposit was exposed to surface          
influences1 the resulting product would 
be oxide of iron from the underlying    
sulphide and a manganiferous iron oxide 
from the overlying isomorphous          
carbonates4 ,hence another possible     
cause of the frequent association of    
pure iron ores and manganiferous iron   
ores4 ,it is possible also that after   
the solution of iron and manganese had  
been freed from the former by           
precipitation as sulphide1 the manganese
 might be carried on and laid down as   
carbonate on a previous deposit of iron 
sulphide1 and when such a combination   
was oxidized1 the result would be oxide 
of iron and oxide of manganese in beds  
closely associated but yet distinct4    
,by supposing the iron sometimes to be  
deposited in sea water as glauconite1 a 
manner in which manganese is not laid   
down 7see page #cfe71 a further means of

 separation of the two metals would     
result4  ,thus by alternating the       
conditions of the deposition of iron and
 manganese in different forms1 a great  
variety of methods of association and   
separation of the two metals can be     
produced4  ,the above discussion refers 
not only to the deposits of iron and    
manganese ores of notable size1 but also
 to the iron and manganese frequently   
found disseminated through shales1      
sandstones etc4 ,in these rocks they    
usually form a small but often a very   
important part1 for in many cases the   
iron and manganese is taken into        
solution from the rocks and redeposited 
by a process of replacement with        
carbonate of lime in neighboring beds of
 limestone1 or more rarely by           
replacement with other rocks1 thus      
giving rise to important ore deposits4  
,the question of the association and    
separation of the iron and manganese in 
these replacement deposits depends on a 
number of conditions1 the principal of  

which are1 just as in the class of      
deposits that has been discussed1 the   
conditions during deposition and the    
forms in which the iron and manganese   
are precipitated4 ,the processes by     
which association and separation occur  
in replacement deposits differ somewhat 
in detail from the processes just       
discussed1 but are based on the same    
principles4  ,many of the iron and      
manganese deposits of the ,appalachian  
region are supposed by many to be       
replacement deposits4 ,n4 ,s4 ,shaler#ca
 in #ahgg suggested that some of the    
iron deposits of ,kentucky and ,ohio    
were formed by the solution of iron from
 certain rocks1 and its deposition in   
the form of carbonates by replacement   
with underlying limestone4 ,subsequently
 it was changed by oxidation to brown   
hematite4 ,a notable case of replacement
 has also been shown by ,r4 ,d4 ,irving 
and ,c4 ,r4 ,van ,hise#cb in the iron   
deposits of the ,penokee series of      
,michigan and ,wisconsin4 ,here the ore 

is supposed to be partly a replacement  
of chert in a trough between quartzite  
and igneous rocks4 ,the solution that   
contained the iron was derived from     
strata in the same series of rocks in   
which the iron was re-deposited and     
contained a certain amount of manganese4
 ,it is shown how the iron and manganese
 were more or less separated in the     
replacement process and that the        
separation was due to the difference in 
the oxidability of the carbonates as    
explained on page #cfc4                 
,r4 ,a4 ,f4 ,,penrose1 ,,jr4            
,,footnotes     #ac ,the exact age of   
the iron and manganese deposits here    
referred         to is1 in some cases1 a
 little uncertain4 ,some may be         
,cambrian1         others ,silurian1 but
 the exact determination of the age of  
the         horizon is not a part of the
 present discussion4 ,the matter has    
been discussed by the writer in         
,geological ,survey of ,arkansas1       
#ahij1 ,vol4 ,i41 pp4 #cgf-cgi4     #ad 

,see ,geological ,survey of ,arkansas1  
#ahij1 ,vol4 ,i41 pp4 #cbj-cbe4     #ae 
,see ,geological ,survey of ,arkansas1  
#ahij1 ,vol4 ,i41 pp4 #def-deg4     #af 
,r4 ,d4 ,irving and ,c4 ,r4 ,van ,hise1 
,u4 ,s4 ,geol4 ,survey1 ,tenth ,ann4    
,report1 #ahhh-ahhi1 ,vol4 ,i1 pp4      
#dji-dbb4     #ag ,geol4 ,survey of     
,penn41 ,vol4 ,,ii1 #aheh1 p4 #gci4     
#ah ,the solutions may be precipitated1 
as already shown1 either         with or
 without admixture with mechanical      
sediments2 and there         are in     
nature all gradations from almost pure  
deposits of iron         and manganese  
ore to beds of shale1 sandstone1 etc4   
stained         with iron or manganese4 
,subsequent concentration frequently    
causes decided changes in the latter    
deposits 7see p4 #cgj74     #ai ,it has 
been suggested by ,a4 ,a4 ,julien       
7,proceed4 ,amer4 ,assoc4         ,adv4 
,sci41 ,vol4 ,,xxviii41 #ahgi1 p4 #cef7 
that in some cases the                  
carbonates of iron and manganese may be 

only the fixed residue         of       
organic compounds of more complex form  
once in solution in         surface     
waters4     #bj ,this oxide is generally
 in the form of the peroxide or the     
sesquioxide in a more or less hydrous   
condition4     #ba ,jahrb4 des ,vereins 
f4 ,naturkunde in ,herz4 ,nassau1 ,vol4 
,,vi41 p4         #afj 7,bischof74      
#bb ,marcasite has the same composition 
as pyrite1 but differs in               
crystalline form4     #bc ,manganese    
also occurs in the mineral youngite1    
which contains         lead1 zinc1 iron1
 manganese and sulphur1 but the mineral 
is         considered of doubtful       
homogeneity4 7,see ,system of           
,mineralogy1         ,e4 ,s4 ,dana1     
#ahib74     #bd ,when manganese is      
precipitated artificially as sulphide it
 is         usually in the form of the  
monosulphide 7,mn,s71 in either a       
hydrous or an anhydrous form4     #be   
,manganese occurs in various            
hydro-silicates1 but they do not        

appear to be deposited as sedimentary   
strata in the same manner         as    
glauconite4     #bf ,if the water moved 
very slowly1 the deposition would       
probably         take place             
approximately in the same spot2 if the  
waters moved         more rapidly1 the  
iron might be deposited in one place and
 the         carbonate in another1 in   
the way explained on page #cfc4     #bg 
,the hydrous oxides of iron are not     
crystalline4     #bh ,see p4 #cfc4      
#bi ,bischof suggests that the action   
described by ,fresenius causes          
the separate deposition of iron and     
manganese2 and also that it             
explains the occurrence of large        
deposits of manganese ore in            
regions where the iron ore contains     
least of that ingredient4         7,see 
,elements of ,chemistry and ,phys4      
,geol41 ,vol4 ,,iii41 pp4               
#eca-ecb47     #cj ,in some cases these 
iron and manganese deposits are         
undoubtedly         formed by the       

replacement of limestone or other rocks1
 as is         further discussed on     
pages -- to --4     #ca ,kentucky ,geol4
 ,survey1 ,report of ,progress1 ,vol4   
,,iii41 ,new         ,series1 #ahgg1 p4 
#afd4     #cb ,u4 ,s4 ,geol4 ,survey1   
,tenth ,annual ,report1 #ahhh-ahhi1     
,vol4 ,i41         pp4 #dji-dbb4        
,,some ,,rivers ,,of ,,connecticut4#cc  
,outline4--,introduction4--,topography  
of ,connecticut3 ,the upland            
plateau1 its origin1 date1 elevation1   
valleys sunk beneath its                
surface4--,lowland on the ,triassic     
area4--,later oscillations4--           
,rsum of the topography4--,early        
drainage4--,re-adjusted streams4        
--,revived streams4--,unconformable     
rivers1 consequent or                   
superimposed4--,pleistocene changes2 the
 ,farmington1 ,quinnipiac1              
,scantic4--,abandoned gaps4             
,introduction4 ,in order to study       
intelligently the history of a river1   
one must first become acquainted with   

the present physical geography of the   
region in which the river lies1 and know
 the stages of its development4         
,therefore1 before classifying the      
rivers of ,connecticut1 ,i shall        
consider the topography of the state1   
and in a few paragraphs outline the     
successive cycles in the history of its 
growth4 ,the scope of this article will 
not permit a discussion or even a full  
statement of the evidence on which these
 conclusions are based4 ,they have been 
stated at considerable length by        
,professor ,w4 ,m4 ,davis1#cd and the   
reader is referred to his papers for the
 complete discussion4 ,his conclusions  
in respect to the physical geography are
 accepted here without question1 and    
form the basis for the discussion on the
 rivers of the state4  ,illustration3   
,,fig #b  ,topography of ,connecticut4  
,connecticut can be said to consist of  
two great areas quite distinct in       
topography and geologic structure4#ce   
,on the east and on the west are the    

crystalline uplands which rise from sea 
level along the ,sound to #a1gjj and    
#a1hjj feet in the northwestern part of 
the state1 and to #fjj and #gjj feet in 
the northeastern4 ,these uplands consist
 chiefly of gneiss and granite1 probably
 of pre-,paleozoic age1 which are now   
much folded1 faulted and crumpled4      
,between these two areas of crystallines
 is a lowland belt of ,triassic         
sandstone and shale1 twenty to          
twenty-five miles wide1 extending from  
,new ,haven north through the center of 
the state and including in its borders  
,new ,haven1 ,meriden1 ,hartford1 ,new  
,britain and many towns of lesser note4 
,these sandstones form a monocline with 
an eastward dip of #aj to #cj1 and in   
addition to being tilted they have been 
faulted since their deposition in a     
shallow1 slowly-subsiding trough of     
crystallines4 ,their thickness is       
variously estimated--#c1jjj to #e1jjj   
feet1 ,dana2 #aj1jjj or more1 ,davis4   
,this lowland is interrupted by a series

 of trap ridges1 which in general       
present steep faces toward the west1    
whereas their eastward slope is gradual1
 less than the dip of the sandstones4   
,the upland plateau4 ,suppose we ascend 
the highest point of these trap ridges1 
the old tower on ,talcott ,mt41 nine    
miles west of ,hartford2 we are #ijj    
feet above the sea level and more than  
#fjj above the plain at our feet4 ,a few
 miles to the west across the sandstone 
valley1 rise the crystalline uplands1   
which extend far to the north and to the
 south4 ,on the east across the         
,connecticut we see the eastern uplands4
 ,the first impression1 which comes to  
one as he gazes upon these uplands and  
which is strengthened with each view1 is
 that few hills rise above the general  
level of the plateau2 the crest line is 
nearly horizontal1 declining gently to  
,long ,island ,sound4 ,above this       
general level are a few rounded domes1  
but no sharp1 towering peaks4 ,below it 
valleys have been cut1 but they do not  

destroy the plateau-like appearance4 ,a 
view from the western plateau across the
 sandstone valley shows the remarkably  
even crest line of the trap ridges1 a   
crest line which approximates in height 
the uplands on the east and west4 ,a    
nearer view of the upland corroborates  
our first impressions of the gently     
rolling character of the inter-stream   
surfaces1 but we have a better view of  
the valleys which have been sunk beneath
 the general level and of the low       
rounded hills which rise above it4 ,in  
popular parlance the country is 8hilly40
 ,it is uneven1 not because there are   
high hills1 but rather because there are
 deep valleys4 ,if in imagination we    
fill up these valleys and the wide      
,triassic lowland to the general level  
of the broad inter-stream surfaces1 we  
shall have constructed a gently         
undulating plateau1 dipping to the south
 and east--a peneplain4#cf  ,origin of  
the peneplain4 ,this is not a           
constructional surface1 for the rocks   

are greatly tilted1 folded and faulted1 
so that the surface consequent upon such
 disturbance must have been complex and 
mountainous4 ,long subarial denudation  
upon a folded and faulted mass when the 
land stood much lower than at present   
produced this plateau4 ,evidently it    
could be produced by denudation only at 
or near baselevel1 for the effect of    
erosion upon a mass high above baselevel
 is to accentuate its topographic       
relief1 not to reduce it4 ,we naturally 
ask ourselves1 8,at what stage in       
geologic history did this denudation    
occur80  ,date of the peneplain4 ,the   
erosion which accomplished this great   
work must have commenced after the      
formation and dislocation of the        
,triassic beds1 for the even crest line 
of the trap ridges1 a part of           
which--perhaps all--were contemporaneous
 with the sandstones1 is a part of the  
dissected peneplain2 but to fix the date
 of the completion of the peneplain1 we 
must turn to evidence presented in ,new 

,jersey4#cg ,there we learn that by the 
close of ,cretaceous times1 the country 
was eroded nearly to baselevel1 and we  
may therefore speak of the relative     
position of the land and sea1 to which  
the land was at this time reduced1 as   
the ,cretaceous baselevel1 and this land
 surface as the ,cretaceous peneplain4  
,elevation of the peneplain4 ,in        
post-,cretaceous1 presumably early      
,tertiary#ch times1 the land was        
elevated to nearly its present height   
and remained at that altitude1 so far as
 topographic evidence shows1 during     
,tertiary times4 ,the proofs of this    
elevation are the valleys which the     
streams have sunk below the general     
level4 ,that this was not a simple      
uplift1 but was accompanied with tilting
 and warping1 is clear from the         
following considerations4 ,the depth to 
which a stream can cut its valley       
depends directly upon its height above  
baselevel4 ,if the present surface were 
a peneplain uniformly elevated1 the head

 waters and middle courses of a river   
would not be cut so deep in the         
surrounding plain as its lower course4  
,but the reverse is true of the rivers  
of ,connecticut4 ,the depth of the      
valley increases inland1 being greater  
in those regions where the peneplain was
 raised the highest4 ,a comparison of   
the upper and lower valleys of the      
,housatonic1 ,naugatuck1 ,quinnebaug1   
and of the ,connecticut at ,middletown1 
where it enters the plateau1 and at its 
mouth1 will give some idea of the amount
 of the warping4 ,it will not give an   
exact measure of it for several reasons3
 first1 the upper courses of the rivers 
have not yet reached the present        
baselevel2 second1 the present altitude 
of the uplands is the result of the     
post-,cretaceous uplift and warping1    
plus a probable later post-,tertiary    
uplift 7to be mentioned later71 besides 
several minor oscillations1 the last of 
which was downward1 and is recorded near
 the coast in the drowned condition of  

the rivers4 ,as has been already said1  
the peneplain is highest in the         
northwest1 and gradually declines to sea
 level toward the south and east4       
,consequences of the uplift4 ,the       
consequences of this uplift are seen in 
the valleys1 which are cut into the     
peneplain1 and which have destroyed the 
level character of the country4 ,in the 
hard crystalline rocks the valleys are  
generally narrow and deep1 with bold    
slopes2#ci where they are cut in the    
crystalline limestone1 they are wider   
and more open4 ,in marked contrast1     
however1 is the lowland on the ,triassic
 area in which only the trap ridges     
remain to tell of the former altitude of
 the general surface1 and the immense   
amount of erosion which has taken place 
on the soft sandstones and shales4      
,indeed erosion has progressed so       
rapidly on these soft rocks1 that they  
have been worn down almost to a new     
baselevel in the same length of time in 
which the hard crystallines have been   

only trenched4 ,this fact cannot be too 
strongly emphasized4 ,the broad         
sandstone lowland from ,new ,haven north
 into ,massachusetts has been carved out
 of the uplifted peneplain in soft      
rocks1 during the same time in which the
 ,connecticut has excavated its gorge in
 the crystallines below ,middletown1 and
 the ,housatonic has opened its upland  
valley on the limestones4 ,the          
difference in results is due not to a   
difference of time1 but to the          
difference in the relative hardness of  
the rocks4  ,on the basis of this       
principle the age of certain river      
gorges to which reference will be made  
later can be fixed4 ,the narrow passage 
of the ,quinnipiac through a sandstone  
ridge southwest of ,meriden cannot      
belong to the same cycle of erosion as  
the broad sandstone lowland on either   
side of it1 but manifestly must be much 
younger4 ,so1 also1 the narrow passage  
of the ,farmington at ,tariffville1     
where it crosses the trap ridge through 

a gorge free from drift1 is of much     
later date than the broader valley more 
or less encumbered with drift which the 
upper part of the same river has cut in 
the hard crystalline schists4 ,cook's   
,gap in the trap sheet west of ,new     
,britain is much broader than either of 
the above1 and belongs to the ,tertiary 
cycle of erosion1 although as ,i shall  
endeavor to show later1 it was probably 
not occupied by a stream during the     
whole cycle4 ,in marked contrast1 also1 
with the ,tariffville gorge is the gap  
by which the ,westfield river in        
,massachusetts cuts the trap ridge4     
,this gap was formerly broad and        
open--the result of ,tertiary           
erosion--but is now filled with drift1  
in which the river is at present        
working4 ,since these two rivers are    
essentially the same in size1 are now at
 the same level1 and the rock is the    
same in both cases1 the only explanation
 for the difference in the two passages 
is that they belong to different cycles4

  ,to recapitulate1 the results of the  
post-,cretaceous uplift are seen in the 
valleys which have been cut in the      
peneplain4 ,the narrow valleys in the   
gneisses and schists1 the upland valleys
 in the limestones1 the wide open1 drift
 encumbered gaps in the trap            
ridge1--,cook's and the ,westfield river
 gaps1--the broad open lowland on the   
sandstones1 are all the result of       
erosion in this cycle4 ,the ,quinnipiac 
gorge in the sandstone1 and the         
,tariffville gorge in the trap are just 
as surely of a later date4 ,they do not 
at all accord with the work of the      
earlier cycle either in size1 angle of  
slope1 or depth4  ,this conclusion is   
somewhat at variance with an opinion    
expressed by ,professor ,j4 ,d4         
,dana1#dj but it seems justifiable in   
view of the successive cycles in the    
physical development of the region4 ,in 
another part of this article ,i shall   
consider these gaps again in connection 
with their river histories1 and shall   

give additional reasons why ,i venture  
to differ from so eminent an authority4 
,length of this cycle4 ,this cycle of   
erosion beginning with the              
post-,cretaceous uplift was not so long 
as the preceding cycle4 ,in the earlier 
one the whole state was reduced to a    
peneplain2 in the later cycle only the  
soft ,triassic sandstones were brought  
near to baselevel4 ,it probably lasted  
through ,tertiary times1 and was brought
 to a close by a slight uplift4 ,the    
result of this uplift is well shown in  
,pennsylvania#da and ,new ,jersey4#db   
,it is not well shown in ,connecticut1  
but there seem to be some traces of it  
in the trenches the rivers have cut     
below the level of the sandstone        
peneplain4 ,however1 these trenches are 
so much obscured by drift that a        
positive statement is not warranted4 ,it
 may1 however1 be spoken of             
provisionally as the post-,tertiary     
uplift4 ,there may have been later      
oscillations of small amount1 probably  

were2 here and there are shreds of      
evidence which point to such            
oscillations1 but only one movement has 
had an effect upon the topography1 which
 can be recognized4 ,the fjorded        
condition of all the rivers along the   
,sound--the ,norwalk1 ,saugatuck1 ,new  
,haven bay1 ,niantic and ,thames are the
 best examples--shows that within       
comparatively recent time there has been
 a slight subsidence of the land4 ,but  
this movement is not to be compared in  
amount with those of the earlier cycles4
  ,the drift4 ,over all the state in    
varying thickness lies the glacial      
drift1 either in its typical unmodified 
development as till1 or in its modified 
form1 as river terraces1 kames1 eskers  
and sand-plains4 ,it is of importance in
 this connection only as it has affected
 the topography of the country and so   
modified the drainage4 ,examples of     
these modifications will be mentioned   
later4  ,rsum4 ,there was first a long  
cycle of denudation in pre-,triassic    

times1 during which the contorted       
crystallines were worn down to a        
comparative level2 second1 a cycle of   
subsidence1 deposition and volcanic     
outburst1 during which the sea entered  
the crystalline trough1 and the         
,triassic conglomerates1 sandstones and 
shales were deposited with the          
intercalated layers of lava2 third1 a   
long cycle of elevation1 folding1       
faulting and erosion1 during which the  
sedimentary beds were elevated--tilted  
into the present faulted monocline1 and 
this constructional surface worn down to
 a baselevel of erosion in late         
,cretaceous times4 ,each of these cycles
 probably represents the sum total of   
several subordinate cycles4 ,there was1 
fourth1 a post-,cretaceous uplift       
inaugurating a period of erosion lasting
 through ,tertiary times and resulting  
in the formation of valleys in the      
hardest rocks1 and a lowland approaching
 baselevel on the ,triassic sandstones  
and shales2 fifth1 a probable late or   

post-,tertiary uplift1 when the valleys 
were deepened and the lowlands          
trenched--obscure in ,connecticut1 but  
well shown farther south2 sixth1 the    
land1 near the coast at least1 is now   
slightly lower than it has been in the  
not remote past1 as is shown by the     
fjords4  ,with the changes of the       
physical geography clearly in mind1 the 
rivers of ,connecticut may now be       
examined in respect to their conditions 
of origin1 the number of cycles through 
which they have lived1 and the approach 
they have made to mature old age4 ,but  
at the very outset a serious difficulty 
is encountered1 for the geological      
structure of the state is nowhere well  
described1 nor have topographic maps of 
all the districts yet been issued4      
,since the structural details are to    
some extent unknown it is unwise in many
 cases to attempt more than tentative   
conclusions4 ,several of the problems to
 be presented cannot be considered as   
settled4 ,considerable progress toward a

 final settlement will have been made1  
however1 if the conditions of the       
problems are made clear1 various        
hypotheses suggested1 and the attention 
of workers in this field called to these
 questions4  ,early drainage4 ,of the   
drainage of ,connecticut during         
,jurassic and ,cretaceous times very    
little can be said4 ,it is not even     
known whether it was consequent upon the
 ,jurassic tilting and faulting1 or     
whether these deformations were so slow 
in their movement that the rivers       
persisted in spite of them4 ,it may have
 been that the larger rivers were       
victorious1 while the smaller were      
conquered and compelled to assume new   
consequent courses4 ,whatever was their 
origin there must have been abundant    
opportunities during the long erosion   
which resulted in the ,cretaceous       
baselevel1 and again in the period of   
revived and quickened degradation       
succeeding the post-,cretaceous uplift1 
for the streams to adjust themselves in 

a large degree to the geological        
structure4 ,the contrast of hard and    
soft beds and the great elevation must  
have been potent factors in bringing to 
pass such a result4 ,we expect to find  
the streams so far re-adjusted as to    
render improbable the discovery of their
 manner of origin4  ,the ,housatonic1 a 
re-adjusted stream4 ,the best example of
 re-adjustment is found in the          
northwestern part of the state where the
 ,housatonic and some of its branches   
follow well adjusted courses4 ,from its 
headwaters1 near ,pittsfield1 ,mass41 to
 ,new ,milford1 ,conn41 it has nearly   
all the way chosen its course along the 
,cambrian crystalline limestones in     
preference to the harder granites and   
gneisses on either side4 ,the           
stratigraphical relationships of the    
limestone are not fully understood1 but 
they seem to be deeply eroded anticlines
 and synclines1 whose axes plunge north 
or south at various angles4 ,the course 
of the river1 if the drainage was       

consequent1 was at first along the      
synclinal valleys1 passing from one to  
another across the lowest points in the 
anticlinal ridge between them4 ,but by a
 series of changes#dc1 resulting from   
the differential rates of erosion as    
hard or soft beds became exposed1 the   
river previously to the ,cretaceous     
baseleveling1 seems to have re-adjusted 
its course to the softer limestones4    
,however1 there are several places where
 this conformity to structure does not  
seem to be the law2 where the river     
departs from a limestone valley to flow 
for a time in the crystallines1 only to 
return to the limestone again4 ,the most
 marked instance of this is in the towns
 of ,sharon and ,cornwall1 where the    
river leaves the limestone valley1 which
 continues to the southwest1 and flows  
for ten miles in a narrow gorge in the  
gneiss1 only to again enter at its      
northern end a long narrow bed of       
limestone4 ,the following seems to be   
the probable explanation4 ,when the land

 stood at the elevation represented by  
the ,cretaceous peneplain1 these hard   
beds were below or but very slightly    
above baselevel1 and were therefore     
undiscovered by the stream or had just  
begun to make themselves known late in  
the cycle4 ,had they been reached early 
in the cycle1 when the stream was far   
above baselevel and presumably before   
many of its tributaries had been        
developed1 and when it was therefore a  
smaller river1 it is quite probable that
 further re-adjustments would have      
occurred1 and the stream been led away  
from the hard rocks onto the softer beds
 to the west2 but when they were reached
 the stream had cut so deeply and so    
nearly to baselevel that it was safe    
from capture4 ,after the elevation of   
the peneplain the stream was revived and
 disclosed more and more of these hard  
beds1 but was then1 owing to the        
development and head-water growth of its
 tributaries1 too important a river to  
be diverted by any rival4 ,a river of   

this kind may be said to be 8conformably
 superimposed0 in distinction to one    
which is superimposed from an           
unconformable cover4  ,revived streams4 
,it is important to recognize the effect
 of the post-,cretaceous uplift upon the
 rivers at that time established4 ,as   
the land was baseleveled and the        
velocity of the streams decreased1 they 
lost in large degree their cutting power
 and sluggishly meandered more or less  
in broad flood-plains4 ,during and for a
 period after the uplift1 their cutting 
power was restored to them by virtue of 
their increased velocity and they       
excavated the deep narrow valleys which 
we find in the crystalline highlands4   
,the upper course of the ,housatonic is 
a good example of a river re-adjusted to
 the structure during one cycle1 revived
 by uplift to a second cycle of erosion1
 and in places 8conformably             
superimposed0 upon structures from which
 it would have been led away in the     
ordinary course of re-adjustment4 ,its  

tributaries1 the ,east ,aspetuck1       
,still1 ,shepaug1 and ,pomeraug follow  
courses re-adjusted in one cycle and    
revived in a later uplift4  ,we can     
assert with the more confidence that    
such was the history of the upper       
,housatonic1 because we find in other   
states1 in regions whose history has    
been the same1 similar examples of      
8conformably superimposed0 and 8revived0
 streams4 ,the ,musconetcong and        
,pequest1 highland rivers of ,new       
,jersey1 are streams 8revived0 from     
mature old age to vigorous youth and    
8conformably superimposed0 upon saddles 
of gneiss between two limestone         
valleys4#dd  ,unconformable rivers4 ,in 
considering the course of the lower     
,housatonic we meet with some difficulty
 at the outset4 ,in the southern part of
 the town of ,new ,milford the river    
leaves the limestone belt which         
continues with some slight interruptions
 to the ,hudson1 and swings sharply into
 the crystalline plateau in a           

southeasterly course until it is joined 
by the ,naugatuck1 when their united    
waters flow south for a few miles to the
 sound4 ,the course of the lower        
,connecticut is even more surprising4   
,at ,middletown it leaves the broad open
 ,triassic sandstone lowland1 and       
through a gorge enters the plateau1     
which has an average elevation of #fjj  
to #gjj feet4 ,in this plateau of       
crystallines the river has sunk its     
valley nearly to sea-level4 ,the slopes 
are steep compared to the lines in the  
sandstone lowland1 and the contrast     
between the two parts of the river is   
one of the striking features of         
,connecticut scenery4 ,several theories 
may be framed to account for the curious
 behavior of these two rivers1 but none 
of them are free from all difficulty4   
,as a consequent river4 ,the lower      
,connecticut has been thought#de to be a
 revived river1 whose course was        
consequent upon the post-,triassic      
tilting and faulting4 ,the faulted      

monocline seems to have had the shape of
 a half-boat1 ends to the north and     
south1 and one gunwale rising toward the
 west1 the combined effect of the       
tilting and faulting being to swing the 
river to the southeast1 where the keel  
of the boat was lowest4 ,the probable   
existence of faults1 with upthrow on the
 east1 along the eastern margin of the  
,triassic rocks1 is a difficulty in the 
way of the complete acceptance of this  
theory4 ,unfortunately too little is    
known about the structure of the western
 plateau to say whether the course of   
the lower ,housatonic could be accounted
 for on such an hypothesis4 ,on this    
theory the ,connecticut would be        
consequent upon the ,jurassic           
deformation1 and revived by the         
post-,cretaceous uplift4  ,it may be    
suggested that the southeast courses are
 due to the tilting of the peneplain at 
the time of elevation1 the plateau now  
being1 as we have seen1 much higher in  
the northwestern part of the state than 

elsewhere4 ,but the acceptance of this  
theory necessitates a degree of         
smoothness and absence of even mild     
relief in the peneplain1 which is hardly
 possible4 ,the present average slope of
 the plateau is but a few feet per mile1
 and it seems incredible that so gentle 
a tilting could force rivers as large as
 these to take new courses4 ,besides1 if
 the ,housatonic and ,connecticut were  
deflected1 why were not the smaller     
streams--the ,naugatuck and             
,quinnebaug--also given southeastern    
deflections8 ,clearly1 this explanation 
is not the correct one4                 
,superimposition4 ,it has been suggested
 that these courses may be inherited    
from a ,cretaceous cover1 which formerly
 stretched over ,connecticut for a      
considerable distance1 but of which no  
traces now remain in the state4 ,on     
parts of ,long ,island the ,cretaceous  
deposits are found1 and it is not       
inherently impossible nor improbable    
that they once stretched far over the   

main land4 ,in ,new ,jersey#df several  
lines of evidence seem to show that the 
,cretaceous beds formerly extended      
across the ,triassic1 probably to the   
margin of the highland plateau4 ,the    
curious drainage of the ,watchung       
,crescent is one evidence of this1 but  
the other proofs are along entirely     
different lines1 so that there is       
apparently good evidence that the       
,cretaceous beds extended twenty-five   
miles or more farther inland4 ,if1 in   
the time which has elapsed since the    
deposition of these beds1 there has been
 erosion sufficient to strip them off   
from such a broad area in ,new ,jersey1 
may they not1 in ,connecticut1 under    
presumably similar conditions1 have been
 equally eroded8  ,there is much which  
makes this hypothesis attractive1 and1  
as the facts were first studied1 it     
seemed the most likely one4 ,it affords 
a good explanation1 not only for the    
courses of the ,housatonic and          
,connecticut1 but also for other rivers 

along the sound4 ,it seems1 also1 at    
first thought1 to be well supported by  
analogy from ,new ,jersey4 ,but a closer
 study of the situation in that state   
reveals marked differences in the       
attendant circumstances4 ,there the soft
 ,triassic sandstone must have been worn
 down to a lowland early in the         
,cretaceous cycle1 perhaps by the close 
of ,jurassic time or thereabouts1 while 
the harder crystallines retained a      
strong relief4 ,the slight subsidence1  
which marked the beginning of marine    
,cretaceous in ,new ,jersey1 allowed the
 ,cretaceous sea to transgress rapidly  
the baseleveled sandstones to the foot  
of the crystalline hills1 but not to    
cover them to any extent4 ,it is not    
probable that the crystallines in       
,connecticut had been brought nearer to 
baselevel than those in ,new ,jersey at 
the time of the ,cretaceous deposits4   
,there is no evidence to show that the  
subsidence was greater in ,connecticut  
than in ,new ,jersey1 and1 therefore1   

from a priori considerations1 the       
conclusion would seem to follow that the
 subsidence1 which permitted the        
,cretaceous sea to cover the ,triassic  
sandstone area of ,new ,jersey1 was not 
sufficient to permit the sea to cover   
the then unsubdued crystalline hills of 
,connecticut4 ,although this hypothesis 
is not to be hastily thrown aside1 for  
theoretical reasons1 yet it would seem  
necessary to hold it very lightly1 at   
least until some positive proof is found
 of the former existence of the         
,cretaceous or some later formation in  
that region4 ,the first suggestion1 that
 the lower ,connecticut was a consequent
 river in the ,cretaceous cycle and was 
revived by the post-,cretaceous uplift1 
is1 at the present state of knowledge1  
the most probable4  ,the ,farmington4   
,the roundabout course of this river    
presents another interesting problem1   
which is not free from difficulties4    
,from its source in ,massachusetts it   
flows southeast across the crystallines 

to the village from which it takes its  
name1 where it turns abruptly north     
along the ,triassic sandstones for ten  
or twelve miles1 when with another wide 
sweep it crosses the trap ridges at     
,tariffville by a deep gorge1 and       
resumes its southeasterly course to the 
,connecticut4 ,of this latter part ,i   
will speak later1 but now arise the     
questions1 8what has been the history of
 this river10 and 8why does it turn     
north at ,farmington80  ,the ,farmington
 in the ,tertiary cycle4 ,a course more 
accordant with the structure would seem 
to be south along the ,quinnipiac and   
,mill river valleys to the sound at ,new
 ,haven4 ,as has been said before 7page 
#cgf71 ,prof4 ,dana has expressed the   
opinion that the gorge at ,tariffville  
was occupied by the ,farmington in      
,tertiary times1 and that the ,westfield
 river gap further north and the gorge  
of the ,quinnipiac southwest of ,meriden
 are also of earlier date than the      
glacial epoch4 ,one reason has also been

 given why ,i differ from him in regard 
to the ,quinnipiac and ,tariffville     
gorges--they are narrower and steeper   
than those made in similar rocks during 
the ,tertiary cycle4 ,but more than     
this1 the constructional topography1    
resulting from the tilting and faulting 
of the region1 could not1 it would seem1
 have caused the ,farmington to take its
 present course4 ,even if it had taken  
this roundabout course during the       
baseleveling of the country1 it must1   
since it would have had to cross three  
trap sheets1 have been captured and led 
to the sea by the shorter and easier way
 along the sandstone area4 ,the fact    
that the ,connecticut probably persisted
 in its consequent course is no argument
 for similar conditions for the         
,farmington1 because the latter is much 
the smaller stream1 and so more easily  
captured4 ,nor could the river have been
 forced into this course during or after
 the post-,cretaceous uplift1 for the   
land was then raised more at the north  

than at the south1 and any changes from 
this cause would have been to confirm   
the river in its southward course4 ,it  
is very probable1 therefore1 that in at 
least the latter part of the ,tertiary  
cycle1 the ,farmington did not have its 
present course1 but followed the open   
sandstone valley1 along the course of   
the ,quinnipiac and ,mill rivers of     
to-day4 ,the earlier history of this    
river is purely conjectural2 one fact   
may shed a little light upon it1 a fact 
which may indicate that this course was 
an adjusted one taken during ,tertiary  
times4  ,in pre-,tertiary times4 ,origin
 of ,cook's ,gap4 ,a few miles southeast
 of where the river emerges from the    
crystallines1 the trap ridge is cut by a
 deep wind notch--,cook's ,gap--through 
which the ,new ,york and ,new ,england  
,railroad passes west from ,new         
,britain4 ,as was pointed out some time 
ago by ,prof4 ,davis1#dg this is not a  
fault gap1 because the alignment of the 
ridge is not broken1 but it is probably 

an abandoned water gap1 the head-waters 
of the stream which formerly occupied it
 having been abstracted by a rival1     
which did not have to cross a hard trap 
ridge4 ,perhaps this river was the      
ancestor of the present ,farmington1 and
 in that case its history would seem to 
have been as follows4 ,a stream         
consequent upon the constructional      
topography after the faulting and       
tilting at the close of the ,triassic1  
it had its upper course on the          
crystallines1 its lower on the          
sandstones and buried trap sheets4 ,in  
its old age it crossed by a shallow gap 
the trap sheet1 which had been uncovered
 by erosion4 ,in the second or ,tertiary
 cycle it was simply a revived stream   
quickened to a new life by the          
post-,cretaceous uplift of the          
peneplain4 ,this uplift gave opportunity
 to a rival stream1 which did not have  
to cross the hard trap beds to intercept
 the waters of the old ,farmington1 and 
lead them out by a shorter1 easier path1

 probably down the sandstone valley west
 of the trap ridge4 ,the path across the
 trap was abandoned1 and the notch      
became a wind gap2 the river following  
its new course1 until the incursion of  
the ice-sheet interrupted its normal    
development4 ,this is of course almost  
entirely speculative4 ,cook's ,gap is   
best explained as an abandoned river    
gap2 the ,farmington is the nearest     
river of a size proportional to the size
 of the gap1 and the hypothesis is a    
rational one4 ,there is1 however1 no    
direct evidence that the ,farmington    
once occupied ,cook's ,gap4  ,the       
,tariffville cut4 ,before attempting to 
answer the second question1 8why the    
river flows north at ,farmington80 let  
us consider for a moment the history of 
the ,tariffville cut4 ,the river        
occupies a gorge whose sides are steep  
and talus covered1 but which is not at  
all clogged with drift4 ,there is       
naturally no room at or near the water  
level1 even for the wagon road1 place   

for which has been blasted near the top 
of the gorge4 ,the profile of the gap   
shows a gentle ascent from the top of   
the gorge1 up to the nearly level crest 
line of the ridge4 ,that is to say1 the 
recent gorge has been cut in the bottom 
of a sag in the ridge4 ,we have already 
given our reasons for believing that the
 gorge here is much younger than the    
,westfield river gap2 that it is a part 
of the work of the next cycle2 that it  
is post-,tertiary4 ,the sag1 however1 in
 the bottom of which the gorge is cut1  
is clearly of the earlier cycle4 ,the   
bottom of the sag is much above the     
level to which the rivers had cut their 
valleys in the late ,tertiary1 and1     
therefore1 it is certain that a river   
could not have occupied it at the close 
of that cycle4 ,it was probably an      
abandoned water-gap whose stream had    
been captured in the same way and in the
 same cycle as the river1 which formerly
 occupied ,cook's ,gap4  ,the fact that 
the sag and gorge1 although located very

 near a fault line1 do not correspond to
 it1 but are transverse and independent 
of it1 is instructive and needs a       
moment's attention4 ,it seems probable  
that the stream consequent upon the     
faulted blocks would have flowed down   
the slope of the tilted block and then  
along the fault line at the foot of the 
fault cliff and would have held this    
course during the baseleveling of the   
country4 ,when the area was baseleveled 
the stream must have swung from side to 
side in its broad flood plain1 and thus 
departed from the fault line4 ,when it  
was revived by the post-,cretaceous     
uplift1 it was confined to the course it
 had unwittingly taken on the sandstones
 just above the hard ridge1 and it was  
forced to cut down through the trap4    
,subsequently a rival1 which did not    
have to work against this obstacle1     
abstracted its head waters and the gap  
was abandoned4 ,the accompanying        
diagrams may make this easier to        
understand4 ,figure #c is a             

cross-section of the faulted monocline1 
,r showing the position of the river    
along the foot of the fault cliff4 ,the 
line ,b ,l represents the surface of the
 country after baseleveling1 the trap   
outcrops forming low hills 7much        
exaggerated in the diagram74 ,figure #d 
shows the dislocated trap sheets1 the   
fault line and the winding course of the
 river1 which has abandoned the fault   
line except where it passes between the 
low trap hills4 ,here the country is at 
baselevel4 ,figure #e represents the    
region after the elevation and resulting
 erosion4 ,the trap ridges have become  
more pronounced1 and have migrated      
eastward in the direction of the dip4   
,the river has been slowly let down upon
 the northern one from the sandstone at 
point ,g and has there cut into the     
solid trap4  ,illustration3 ,,figures   
#c-e4  ,the transverse notch of ,cook's 
,gap1 already described1 was probably   
located in a somewhat similar manner1   
but the case is not so clear as at      

,tariffville4  ,gravel terraces of the  
,farmington4 ,a consideration of some   
facts concerning the height and slope of
 the terraces along this part of the    
river may give a clue to the answer to  
our question4 ,one-half a mile east of  
,tariffville and east of the trap ridge1
 the highest terrace is #baj to #bae    
feet4 ,half a mile south of the same    
place but west of the ridge the height  
is #bge feet4#dh ,the top of the gorge  
at ,tariffville is about #aij feet above
 the sea-level4 ,it does not seem       
probable that these highest terraces    
were ever continuous over all the       
,farmington valley4 ,but if they        
represent the level reached by the      
maximum flood accompanying the melting  
of the glacier1 the great difference in 
their height on the two sides of the    
trap ridge1 in connection with the other
 evidence already noted1 gives strong   
reason for believing that the gorge as  
it exists to-day had not then been cut4 
,a mile and a half east of ,tariffville 

there is a lower terrace which is       
wide-spread4 ,its general height is     
about #aij feet1 in places a little     
more4 ,in this terrace the lower part of
 the ,farmington has cut a trench #ij to
 #ajj feet deep4 ,the shape of the      
valley makes clear the fact that before 
this trench was cut the river flowed at 
about the #aij foot level1 which is the 
height of the bottom of the sag at      
,tariffville4 ,on the west side of the  
trap ridge there is also a more or less 
wide-spread terrace at about the same   
height4 ,it seems very probable         
therefore that the river was raised to  
the level of the old sag in the trap    
ridge by the building of these terraces4
  ,the present average southward slope  
of the highest terraces west of the trap
 ridge from ,northampton1 ,mass41 to    
,farmington1 ,conn41 forty-four miles1  
is seven inches per mile1#di and        
,professor ,dana is inclined to believe 
that this is approximately the slope at 
the time the terraces were built4 ,the  

character of the deposits shows that the
 current which formed these deposits    
flowed south4 ,the present river1       
flowing north1 falls twenty feet between
 ,farmington and ,tariffville1 or #a    
feet per mile4 ,the reversal of the     
river was probably determined by two    
factors4 ,near the village of           
,farmington1 the waters of #bjj square  
miles of territory are poured into the  
valley by the upper ,farmington and its 
tributary1 the ,pequabuck4 ,during the  
terrace building stage the great mass of
 dbris contributed by these streams was 
deposited where the steep gradient of   
the highlands was exchanged for the     
gentle slope of the lowland4 ,the main  
north and south valley was thus choked  
by the dbris of its tributaries and a   
long stretch of comparatively still     
water extended north from ,farmington1  
in which nearly horizontal deposits were
 made4 ,south of ,farmington the terrace
 deposits are much coarser than to the  
north1 and the face of the terraces is  

much greater4 ,it is not impossible     
that1 as the deposits between           
,farmington and the ,massachusetts state
 line approached nearer and nearer to   
horizontality1 the waters of the upper  
,farmington began to divide1 part       
flowing north and part south1 the       
northward flowing portion finding an    
outlet at the sag at ,tariffville4 ,if  
this was the case1 the terraces between 
,farmington and ,tariffville must have  
had a slight slope to the north4 ,their 
present southward slope could readily be
 accounted for by the re-elevation of   
the land after the disappearance of the 
ice4 ,this explanation rests upon the   
ability of the upper ,farmington and the
 ,pequabuck to have completely dammed   
the southward flowing current and turned
 it northward by the great mass of their
 deposits4 ,if this was not the case1   
and there may be some doubt on the      
matter1 the subsidence which accompanied
 the later stages of the ice-retreat is 
the other factor in the problem4 ,it is 

estimated that an average depression of 
#a4be feet#ej through the ,connecticut  
valley would restore it to an altitude  
approximating that at the close of      
glaciation4 ,it seems highly probable   
that these terrace-deposits were built  
before the maximum depression was       
reached4 ,if this was the case1 the     
depression would be efficient in        
reversing the ,farmington1 and this     
factor would supplement the first4 ,it  
is impossible at present to say to what 
extent these two factors enter into the 
problem4 ,that they are not mutually    
exclusive is evident1 and that they are 
together quantitatively competent seems 
certain4 ,among the several hypotheses  
which have been considered1 this seems  
the most probable1 and in the light of  
the present evidence the most rational4 
,at first thought it might seem that if 
the ,farmington was reversed by the     
differential subsidence of the land1 the
 ,connecticut ought to have suffered a  
similar fate1 and since it did not1 the 

explanation cannot apply to the         
,farmington4 ,but the terraces of the   
,connecticut have a much greater        
southward slope than those on the       
smaller river1 and the depression was   
not sufficient to reverse the stream4   
,the conditions on the two sides of the 
trap ridge were not the same4  ,to sum  
up1 then1 the history of the ,farmington
 seems to have been as follows3 ,its    
original consequent course was southeast
 on the crystallines and perhaps across 
the trap ridge at ,cook's ,gap1 from    
which course it was turned in the       
,tertiary cycle by a stream whose course
 was approximately that of the ,mill    
river of to-day4 ,the damming of the    
valley by the deposits of the ,upper    
,farmington1 and the depression in the  
north accompanying the ice retreat1     
reversed the river at ,farmington1 and  
it took a new course on the terrace     
deposits1 escaping by the sag in the    
trap at ,tariffville into the           
,connecticut valley4  ,the ,quinnipiac4 

,the gorge of the ,quinnipiac1 already  
mentioned several times1 seems closely  
comparable to the gorge of the          
,farmington4 ,it is not of the ,tertiary
 cycle1 and is best referred to the     
inter-glacial or post-glacial epochs4   
,we should expect the ,quinnipiac1      
instead of turning eastward1 to cut     
through this sandstone ridge1 to        
continue southward along the ,mill river
 valley4 ,dana#ea finds from the heights
 of the terraces that the drainage of   
the terrace-building period was not     
along the ,quinnipiac1 but along the    
,mill river1 and concludes that the     
,quinnipiac gorge was obstructed by an  
ice-dam4 ,i have not as yet studied it  
enough in detail to do more than express
 the opinion here reiterated1 that this 
gorge is later than the cycle in which  
the open sandstone lowland on either    
side of it was excavated4 ,its          
topographic form would put it in the    
cycle which has been called             
post-,tertiary4  ,the ,scantic4 ,in the 

,scantic we have a typical example of a 
river whose lower course is manifestly  
of a later date than the upper4 ,in this
 it is similar to several of our        
,atlantic rivers1 notably those of      
,north ,carolina1 whose upper courses   
are on the ,piedmont crystallines1 being
 probably established previous to the   
,cretaceous baseleveling1 and whose     
lower courses stretch seaward over the  
unconsolidated ,tertiary deposits of the
 coastal plain4 ,as the plain of these  
recent deposits emerged from the sea1   
the rivers were forced to extend their  
courses eastward over the freshly raised
 surface to the retreating shore line4  
,the ,scantic river has a similar       
history4 ,its upper course in southern  
,massachusetts on the crystalline       
plateau is a remnant of the drainage    
established before ,cretaceous          
baseleveling and revived by the         
subsequent uplift4 ,how much that       
revived drainage has been modified by   
drift can only be determined by long    

field study1 but the topography1 as read
 from the topographical atlas would seem
 to indicate1 that it has not been much4
 ,the valleys were undoubtedly clogged  
with drift1 and the drainage area may be
 somewhat modified1 but the drainage    
seems to be substantially along the same
 lines4  ,just below the village of     
,hampden1 the ,scantic leaves the       
plateau and enters the ,triassic        
lowland4 ,from this point to its mouth  
at the ,connecticut1 opposite ,windsor1 
a distance of twenty miles1 it flows    
nearly all the way through the gravel1  
sand and clay deposits of the period of 
ice-retreat4 ,the topography of the     
lower course of the river is entirely   
characteristic of a stream which has    
recently attacked a level1 easily eroded
 district4 ,the inter-stream surfaces   
are broad and flat2 the descent to the  
stream bed which is sunk seventy or     
eighty feet below the general surface is
 exceedingly steep4 ,these two lines1   
that of the inter-stream surface and    

that of the valley side1 meet at a sharp
 angle4 ,the side streams are as yet    
very short1 and have cut narrow gorges  
down to the main river4 ,tributary to   
them are deep side ravines1 whose       
bottoms ascend rapidly to the           
inter-stream surface1 the whole making a
 dendritic system of drainage in its    
earlier stages4 ,the ,scantic1 having   
reached base level in its lower course1 
has developed a narrow flood-plain4     
,manifestly this part of the river      
valley is of much later date than the   
upper part4 ,if1 during the period of   
ice-retreat1 the lower ,connecticut     
valley was an estuary1 the ,scantic was 
a much shorter river than at present4   
,its mouth could not have been far from 
the point where now it leave the        
crystallines1 but as the land was       
elevated and estuarine conditions gave  
place to fluviatile1 the ,scantic       
lengthened 8mouthward10 consequent upon 
the minor inequalities of the newly made
 beds4 ,the effect would be             

substantially the same if the terraces  
were built by great valley floods1 as   
,dana supposes4 ,in pre-glacial times   
this river1 in common with several other
 rivers rising on the crystallines and  
flowing into the ,connecticut1 had      
courses of various lengths over the     
,triassic sandstones1 but these old     
valleys are lost entirely1 the later    
trenches in the terrace deposits being  
altogether independent of them4  ,other 
examples4 ,the lower ,hockanum1         
,farmington1 ,park1 and the entire      
length of many short streams are similar
 to the lower ,scantic1 and originated  
under similar conditions4 ,stony ,brook1
 a little stream north of ,windsor      
,locks1 presents the same features1 but 
with this variation3 ,it is superimposed
 through a thin layer of drift upon the 
sandstone1 into which it has cut a deep1
 picturesque gorge4 ,the ,hockanum and  
,farmington are also 8locally           
superimposed0 in a few places4 ,the     
,connecticut1 also1 north of            

,middletown1 although following its     
pre-glacial valley1 has departed in     
numerous places from its former bed1 and
 has cut down through the valley-filling
 onto ledges of rock beneath4 ,the      
water-power at ,enfield1 ,conn41 and at 
,turner's ,falls and ,bellows ,falls1   
,mass41 is the result of this           
superimposed position4  ,abandoned gaps4
 ,many abandoned water-gaps must exist  
among the hills of the state4 ,cook's   
,gap1 through which the ,new ,york and  
,new ,england ,railroad crosses the trap
 ridge1 three miles west of ,new        
,britain1 has already been discussed4   
,it must not be confounded with the     
majority of the other gaps in the trap  
ridge1 which are oblique1 break the     
alignment of the ridge1 and are due to  
faults4  ,the ,new ,york and ,new       
,england ,railroad in ascending to the  
eastern plateau passes through ,bolton  
,notch1 a few miles east of ,manchester4
 ,this notch1 also1 is an abandoned     
river bed but1 as it seems1 abandoned at

 a later date and for another reason    
than that assigned for ,cook's ,gap4    
,the drift is very heavy in this region1
 and the most probable explanation is   
that the post-glacial streams do not    
altogether follow pre-glacial valleys4  
,this gap1 used by turnpike and         
railroad1 testifies of another and older
 drainage system4  ,that in this brief  
article all the problems connected with 
the ,connecticut rivers have been       
solved1 or even noted1 is not to be     
expected4 ,it is hoped1 however1 that   
the work done may prove a help to       
further study of the same regions1 and  
that the tentative conclusions advanced 
may be substantiated by further         
investigation4                          
,,henry ,b4 ,,kummel4   ,,footnotes     
#cc ,the author desires to express his  
obligation to ,professor         ,w4 ,m4
 ,davis for aid in the preparation of   
this article4 ,it         was first     
written under his direction and with the
 help of         his suggestions when   

the author was in the graduate school of
         ,harvard ,university4 ,prof4   
,davis is not responsible1 however1     
for the statement of the views herein   
advanced1 although in         general it
 is believed that he is in accord with  
them4     #cd ,amer4 ,jour4 ,sci4 #c;d  
ser41 vol4 xxxvii1 #ahhi1 p4 #dbc4      
,bull4         ,geol4 ,soc4 ,amer41 vol4
 ii1 p4 #ede4     #ce ,the rough        
diagrams accompanying this paper may aid
 the         reader who is unacquainted 
with the details of the region          
under discussion4 ,the abbreviations on 
the above figure are         as follows3
 ,c4 ,the ,connecticut4 ,cr4 ,pl4       
,crystalline plateau         7the shaded
 area74 ,f4 ,the ,farmington4 ,h4       
,hartford4 ,ho4 ,the                    
,housatonic4 ,lm4 ,limestone area4 ,m4  
,meriden4 ,mi4 ,mill ,river4 ,mt4       
,middletown4 ,n4 ,the ,naugatuck4 ,n4   
,h4 ,new ,haven4 ,no4 ,the ,norwalk4    
,q4 ,the ,quinnipiac4 ,qg4 ,the         
,quinnebaug4 ,s4 ,the ,scantic4 ,sa4    

,the         ,saugatuck4 ,t4            
,tariffville4 ,th4 ,the ,thames4 ,the   
unshaded area         is the ,triassic  
sandstone lowland1 and the blackened    
areas         represent the ridges of   
the faulted trap sheets4     #cf ,am4   
,jour4 of ,sci41 #c;d ser41 vol4 xxxvii1
 p4 #dcj4     #cg ,bulletin of ,geol4   
,soc4 of ,amer41 vol4 ii1 p4 #eed4      
#ch ,it is not desired to affirm that   
these periods of erosion and            
elevation began and ended promptly with 
the beginning or end         of a       
period4 ,the time statements must be    
considered as only         approximate4 
#ci ,an exaggerated idea must not be had
 of the steepness and         narrowness
 of these crystalline valleys4 ,the     
valley of the         ,farmington1 five 
miles up from where it opens into the   
,triassic         sandstone1 is #djj to 
#ejj feet deep1 and a mile and a half   
wide         at the top4 ,the           
,connecticut valley1 just below         
,middletown1 is         about #djj feet 

deep and two miles wide at the top4     
,these are         fair representatives 
of the valleys in the crystalline rocks 
in         the central part of the      
state4     #dj ,amer4 ,jour4 of ,sci41  
vol4 x1 #c;d ser41 #ahge1 p4 #ejf4      
#da ,mc,gee4 ,amer4 ,jour4 ,sci41 #c;d  
ser41 vol4 xxxv1 p4 #cgf4     #db ,davis
 and ,wood1 ,geographic ,development of 
,northern ,new ,jersey1         pp4     
#dac1 #dad4     #dc 8,rivers and        
,valleys of ,pennsylvania10 ,davis1 ,w4 
,m41 published         in ,the ,national
 ,geographic ,magazine1 in #ahhi4       
#dd ,davis1 ,w4 ,m41 8,geographic       
,development of ,northern ,new ,jersey10
         p4 #cig-h4     #de ,davis1 ,w4 
,m41 ,amer4 ,jour4 of ,sci41 #c;d ser4  
vol4 xxxvii41 #ahhi1         p4 #dcb4   
#df ,geog4 ,devel4 of ,northern ,new    
,jersey1 p4 #djd et seq4 ,proc4 ,bos4   
,soc4 ,nat4 ,hist4 ,also ,rivers of     
,northern ,new ,jersey1 p4 #aa et       
seq4 ,national ,geographic ,magazine1   
vol4 ii1 p4 #ic4     #dg ,faults in the 

,triassic ,formation near ,meriden1     
,conn4 ,bulletin         of the ,mus4   
,comp4 ,zol4 ,harvard ,univ4 vol4 xvi4  
,no4 #d1 p4 #hb4     #dh ,j4 ,d4 ,dana1 
,amer4 ,jour4 ,sci4 #c;d4 ser41 vol4 xv1
 p4 #ejf4     #di ,j4 ,d4 ,dana1 ,amer4 
,jour4 of ,sci4 #c;d ser4 vol4 xxv1 p   
#ddf4     #ej ,j4 ,d4 ,dana1 ,amer4     
,jour4 of ,sci41 #c;d ser41 vol4 xxiii1 
p4 #aih4     #ea ,j4 ,d4 ,dana4 ,amer4  
,jour4 ,sci41 #c;d ser41 vol4 xxv1 p4   
#dda4     ,,studies ,,for ,,students4   
,,geological ,,history ,,of ,,the       
,,laurentian ,,basin4   ,the study of   
the ,pleistocene history of the basin   
drained by the ,st4 ,lawrence has been  
fragmentary and is still far from being 
complete4 ,there is a lack of agreement 
in the interpretation of observations   
already made1 due in part to the        
comparatively limited portion of the    
field examined even by those who have   
given the subject most attention1 and in
 part to lack of uniformity in the      
standards of comparison used4 ,it is    

with the hope of assisting in reaching  
more harmonious results that attention  
is here invited to methods of study4    
,in the present treatment of the subject
 it may be advantageously subdivided1   
and the facts and hypotheses relating to
 each division separately considered4   
,of the divisions that may be suggested 
the following seem the most important3  
#a4 ,character of the sub-morainal or   
hard-rock topography in the ,laurentian 
basin4  #b4 ,origin of the basin4  #c4  
,sedimentary deposits4  #d4 ,shore      
markings left by former water-bodies4   
#e4 ,fossils in ancient sediments1 shore
 ridges1 terraces1 etc4  #f4 ,fauna of  
the present lakes4  #g4 ,changes in     
elevations of the land4  #h4 ,former    
outlets4  #i4 ,probable effects of an   
ice sheet on drainage4  #aj4 ,probable  
effects of a subsidence which would make
 the basin an arm of the sea4  #a4      
,character of the hard-rock topography4 
,in order to learn the character of the 
,laurentian basin it is necessary to    

examine the rock surface beneath the    
general covering of glacial dbris and   
stratified sediments which partially    
fill it4 ,to do this1 those areas in    
which rock in place forms the surface   
require to be mapped and their          
elevations noted2 the records of wells  
and other excavations which pass through
 the superficial deposits should also be
 obtained and the character of the      
underlying rock ascertained1 as far as  
is practicable4 ,when sufficient data of
 this nature shall have been recorded1 a
 contour map of the basin can be drawn  
that will reveal the shape of the       
depression with which the student has to
 deal4 ,the depth of the present lakes  
plus an estimated thickness of clay and 
morainal material covering their        
bottoms1 will probably furnish the only 
means of sketching contours over the    
deeper portions of the basin4 ,even an  
approximately accurate map of this      
character cannot be constructed for a   
long time to come1 but every advance    

towards it will serve to make the       
problems to be studied more and more    
definite4  ,something of the form of the
 rock-basin is already known and several
 deep channels in its borders1 now      
filled with drift1 have been discovered4
 ,the courses of buried channels        
connecting the basins of some of the    
present lakes have also been            
approximately determined4 ,it is not    
necessary at this time to refer         
specifically to the discoveries that    
have been made1 but it may be stated    
that enough is known to assure us that  
the basin is a depression in solid rock1
 the bottom of which is below sea level4
  #b4 ,origin of the basin4 ,the rocks  
in which the ,laurentian basin is       
situated are1 with the exception of the 
,lake ,superior region1 nearly          
horizontal and belong almost wholly to  
the ,paleozoic4 ,the basin is           
essentially a depression in undisturbed 
strata1 and all who have considered its 
origin seem agreed that it has been     

formed by excavation4 ,a vast mass of   
horizontal strata has been removed1     
leaving an irregular rim of undisturbed 
rocks on all sides4 ,the form of the    
depression is now obscured by drift2 the
 deeper portions contain stratified     
sediments which have been deposited     
within it and it has been warped        
somewhat by orographic movement4  ,the  
manner in which the excavation was      
formed has been explained principally in
 two ways4 ,one hypothesis is that it   
owes its origin to a time of subarial   
denudation preceding the ,glacial epoch1
 during which a valley1 or series of    
valleys1 was worn out by stream erosion2
 and that the depression thus produced  
has been but slightly modified by ice   
action4 ,the closing of the ancient     
valley has been referred to orographic  
movements and to the filling of its     
outlet by glacial dbris4 ,another       
hypothesis is to the effect that the    
excavation is mainly due to ice erosion 
during the ,glacial epoch1 without      

special reference to previous           
topographic relief4 ,a warping of the   
earth's crust so as to produce a true   
orographic basin does not seem to       
require consideration1 for the same     
reason as already stated1 that the rocks
 in which the basin lies have been but  
little disturbed from their original    
horizontal position4 ,future study of   
the region must determine which of the  
two hypotheses outlined above best suits
 the facts2 or if each hypothesis has   
something in its favor1 what combination
 of the two may be accepted as the final
 explanation4  ,it is a suggestive fact 
in connection with the first of these   
hypotheses1 that the youngest rocks in  
the region antedating the ,pleistocene  
belong to the ,carboniferous4 ,this     
seems to show that the land has not been
 submerged since at least the close of  
the ,paleozoic4 ,if not a region of     
sedimentation during this vast interval1
 it must have been subjected to erosion4
 ,the erosion of an ancient land surface

 might result in the production of      
topographic forms of diverse character1 
depending on its altitude1 on the length
 of time it was exposed to atmospheric  
agencies during various stages of       
elevation1 and on climatic and other    
conditions4 ,the study of topographic   
forms is now sufficiently advanced to   
enable one to predict somewhat          
definitely what features would appear   
under certain conditions4 ,we also know 
the characteristics of topographic forms
 due to glacial erosion4 ,it seems      
evident1 therefore1 that a knowledge of 
the hard-rock topography in the         
,laurentian basin1 would enable one to  
draw definite conclusions in reference  
to the part that ice and water each had 
in shaping the forms now found there4   
,the conclusion that the region under   
consideration has been glaciated is well
 established2 it remains1 therefore1 to 
determine what topographic forms1 if    
any1 due to pre-glacial stream erosion  
can be recognized4 ,as an example of    

this kind of evidence desired1 attention
 may be directed to the northward facing
 rock escarpments which follow the      
southern shores of lakes ,erie and      
,ontario for a large part of their      
courses and at varying distances up to  
several miles4 ,these escarpments are   
composed of the edges of nearly         
horizontal strata1 mostly of ,paleozoic 
limestone1 and their bases are buried   
beneath glacial dbris and stratified    
clays so deeply that in some instances1 
at least1 they do not reveal half of    
their actual height4 ,these escarpments 
not only have ,pleistocene deposits     
banked against them1 but their faces and
 summits are polished and grooved1      
showing how stubbornly they resisted the
 invasion of the ice which impinged     
against them from the north4 ,south of  
lake ,ontario especially1 the trend of  
the escarpment referred to is directly  
athwart the course of the ancient       
glaciers4 ,the entire history of these  
escarpments cannot be discussed here1 as

 my desire is simply to call attention  
to the fact that they existed before the
 ,glacial epoch1 and are relics of a    
strongly accented pre-glacial           
topography4 ,they are within the        
southern border of the ,laurentian      
basin1 and hence afford means of        
determining1 in part1 what was the form 
of that basin before it was modified by 
ice action4 ,other similar escarpments  
exist in the northern and western       
portions of the same great basin1 and as
 this study progresses it is to be      
expected that still other features of   
the pre-glacial land will be revealed4  
,it is perhaps too early to decide what 
were the special topographic forms which
 gave character and expression to the   
,st4 ,lawrence basin before the ice     
invasion1 but the ,erie and ,ontario    
escarpments and some other similar      
features now recognized1 suggest that in
 ,tertiary times it resembled the       
present condition of the upper portion  
of the ,mississippi valley1 where bold1 

rock escarpments border wide stream-worn
 depressions4  ,deep drift-filled       
channels are known to cut across the    
,erie and ,ontario escarpments4 ,these  
seem to have been formed by streams     
tributary to the main drainage line to  
the north4 ,if this conclusion is well  
founded1 a study of the hard-rock       
topography should reveal other similar  
channels and finally indicate a well    
matured drainage system4 ,if even the   
broader and stronger features of the    
pre-glacial surface can be determined1  
then the modifications due to glacial   
abrasion will become conspicuous1 and   
the amount that glaciers have broadened 
and deepened the basin be determinable4 
,a study of the lithological character  
of the drift south of the present lakes 
should show1 at least in a rough way1   
what portion of it was derived from the 
waste of rocks within the ,laurentian   
basin4 ,this inquiry has already been   
undertaken by at least two geologists1  
and estimates of the quantity of        

material removed from the basins of     
lakes ,michigan and ,erie respectively1 
have been made4 ,this method may be     
extended so as to embrace a larger area1
 or some special portion of the great   
depression best suited for the trial may
 be selected4 ,if the material removed  
from the basin or re-distributed within 
it by glacial action can be shown to be 
approximately equivalent in volume to   
the amount of rock excavated in order to
 form the depression1 it would evidently
 tend to support the hypothesis of      
glacial erosion4 ,if1 on the contrary1  
the amount of dbris derived from the    
basin should fall far short of what     
would be requisite to refill it1 no very
 definite conclusion would seem to be   
indicated unless account could also be  
taken of the fine material carried away 
by glacial streams4  ,as the case stands
 at present it appears that there is    
evidence of a pre-glacial valley or     
series of valleys as has been claimed by
 several geologists1 and that all but   

the boldest features of the old         
topography have been obliterated or     
greatly modified by glacial erosion     
followed by glacial and other           
sedimentation4 ,additional observations 
should show somewhat definitely the     
amount of work assignable to particular 
portions of the history4 ,how far the   
results of subarial and of glacial      
erosion have been modified by other     
agencies1 more especially by orographic 
movements1 has also to be considered4   
,if the ,st4 ,lawrence basin shall be   
shown to be largely the result of       
subarial erosion it will follow1 unless 
it is found that the deeper portions are
 the result of glacial action1 that the 
land at the time the streams did their  
work1 must have stood higher than at    
present1 for the reason that the bottom 
of the depression is now below sea      
level4 ,some idea of the smallest amount
 of elevation necessitated by this      
hypothesis might be obtained by         
estimating the gradients of the ancient 

streams and the amount of elevation     
required to bring the bottom of the     
depression up to sea level4  ,a study of
 the hard-rock topography in the valleys
 of the ,ottawa and ,st4 ,lawrence and  
of the present submerged ,atlantic      
border of the continent would also be   
instructive in this connection4 ,the    
strict correlation of the topographic   
history of the interior and of the      
continent's margin may be difficult1 but
 as the two regions are directly        
connected1 valuable results should      
follow their comparative study4  ,the   
hypothesis that the ,laurentian basin is
 due largely to pre-glacial erosion1    
necessitates also that the ancient      
system of river valleys should have been
 closed in some way so as to form the   
basins of the present and of former     
lakes4 ,the closing has been referred to
 several agencies4 ,an unequal          
subsidence following the period of      
stream erosion has been postulated4     
,during the ,glacial epoch the entire   

region was ice-covered and only glacial 
streams of one kind or another could    
have existed4 ,on the retreat of the    
ice1 when portions of the basin were    
abandoned1 the drainage is supposed to  
have been obstructed by the ice itself1 
as will be noticed below4 ,when the     
glaciers melted1 a vast sheet of dbris  
was left which in many instances filled 
or obstructed previous drainage lines4  
,old channels1 now deeply buried1 have  
been reported to connect the basins of  
the various existing lakes1 as has      
already been mentioned1 but no similar  
channel which could have afforded an    
escape for the waters of the entire     
basin has been discovered4 ,here again  
an acquaintance with the hard-rock      
topography should give assistance and   
indicate either that such a channel     
existed or that orographic movements    
have taken place which have obstructed  
the former drainage system4 ,the glacial
 hypothesis assumes that the basin was  
excavated mainly by glacial abrasion and

 does not require that the land should  
be either higher or lower than at       
present4 ,the study in this direction   
merges with that of the general         
glaciation of the northeastern part of  
the continent1 and cannot be treated at 
this time4  #c4 ,sediments4--,regularly 
stratified deposits of clay and sand    
occur along many portions of the borders
 of the present ,laurentian lakes4      
,these were clearly formed in water     
bodies which formerly existed within the
 ,laurentian basin1 and which in certain
 directions1 at least1 were of wider    
extent than the present lakes4 ,the     
areas occupied by these deposits have   
been partially mapped1 but much remains 
to be done in this direction4 ,fresh    
sections1 particularly of the stratified
 clays1 are exposed from time to time by
 artificial excavations1 in which much  
of their history may be learned4 ,not   
only should records be made of the facts
 noted at special excavations1 but the  
extent and character of the stratified  

deposits in one area should be          
determined and compared with similar    
data obtained in other areas4 ,for      
example3 the clays covering large tracts
 on the west shore of ,lake ,michigan   
and on the southern and western border  
of ,lake ,superior are of a red color1  
while other areas bordering ,lake ,erie 
are covered with blue clay4 ,these two  
deposits have been supposed to have been
 laid down at the same time and in the  
same lake4 ,the definite correlation of 
the clays of these two areas by direct  
contact1 however1 does not seem to have 
been made1 and there are reasons for    
thinking that they may be quite distinct
 and that they originated in separate   
lakes4  ,the outer limits of the        
deposits of clay and sand here referred 
to are known in some instances to be    
determined by ancient beaches and       
terraces4 ,such associations of deep and
 of shallow water deposits require      
special attention1 as the study of one  
may assist in interpreting the          

significance of the other4 ,the fine1   
evenly stratified clays frequently      
contain large angular bowlders1 which   
appear to have been dropped from        
floating ice and to show an intimate    
connection between the ancient lakes and
 neighboring glaciers4 ,the possibility1
 however1 of the bowlders having been   
brought into the ancient water bodies by
 rivers1 or floated outwards from the   
shore by lake ice1 should also be       
considered4 ,huge angular masses of     
limestone have been reported as         
occurring in southern ,michigan         
especially1 which rest on superficial   
deposits and are thought to have been   
carried northward by lake ice4 ,the     
relations of these masses to well       
defined shore lines have never been     
determined4 ,if it should be found that 
they are above all former shores1 it is 
evident that they must have been carried
 by some other agency than the one      
mentioned4  ,a chemical examination of  
the clays1 or of their contained water1 

may indicate whether or not the basin   
was formerly in direct communication    
with the ocean4 ,analyses of the clays  
of the ,champlain valley and of the     
similar clays in the ,ontario and ,erie 
basins might indicate whether or not    
they were deposited under similar       
conditions4  #d4 ,shore records4        
,beaches and terraces have been studied 
at many localities about the borders of 
the present lakes1 sometimes at a       
distance of more than twenty miles from 
their margins and at various elevations 
up to several hundred feet above their  
surfaces4 ,in some instances these      
ancient shore records have been followed
 continuously for scores of miles4 ,the 
tracing and mapping of individual       
beaches is one of the most important    
parts of the study here outlined1 and is
 already well advanced4 ,confusion has  
unfortunately arisen1 however1 for the  
reason that topographic features1 due to
 shore action1 have1 in some instances1 
been confounded with somewhat similar   

features due to other causes4 ,moraines 
and gravel ridges1 formed by glacial    
streams1 have been mistaken for beach   
ridges1 and terraces of various origin  
have not been clearly discriminated4    
,in order not to be led astray by       
topographic forms that simulate shore   
phenomena1 the student should examine   
the shores of existing lakes and learn  
what records are there being made4 ,in  
the study of topography1 8the present is
 the key to the past10 just as          
definitely as in any other branch of    
geology4 ,the topography of lake shores 
has already received attention from one 
skilled in reading geological history in
 the relief of the land#eb and the study
 of existing shores in the light of what
 has already been done in that direction
 should enable even the beginner to     
avoid falling into serious error in     
interpreting ancient records of the same
 nature4  ,to be able to discriminate   
clearly between shore features and      
somewhat similar glacial phenomena1 it  

is necessary to become familiar also    
with the topography of glacial deposits4
 ,fortunately in this study also a guide
 is at hand#ec which1 in connection with
 field observations1 should soon train  
the eye to discriminate the shapes      
assumed by moraines and the deposits of 
glacial streams from all other          
topographic forms4  ,in examining the   
records of former lakes it will soon be 
observed that1 in many instances1 where 
the highest of a series of ancient      
beaches is obscure and indefinite1 the  
topographic expression above and below a
 certain horizon1 and also the character
 of the surface material1 whether of the
 nature of lacustral clays and sands or 
of glacial dbris1 residual clay1 etc41  
above and below the same level1 are     
significant1 and enable one to map the  
outline of a former water body with     
considerable accuracy4  ,in tracing     
ancient beaches and terraces1 their     
forms and internal structure need to be 
recorded1 so that the fact of their     

being true shore records may be made    
plain to others4 ,the elevations of     
various well-defined points throughout  
the extent of an ancient shore should be
 carefully measured1 for1 as will be    
noticed below1 although originally      
horizontal1 they have1 in many          
instances1 been elevated or depressed1  
owing to broad general movements of the 
earth's crust4 ,the continuous tracing  
of individual shore lines for as great a
 distance as possible is highly         
desirable1 especially in a wooded       
country1 in order to be positive as to  
which ridge or terrace measurements of  
elevation relate1 and also for the      
purpose of observing the nature of the  
changes that occur when a shore line    
gives place to other records4 ,for      
example3 some of the ancient beach      
ridges about the west end of ,lake ,erie
 have been found to be continuations of 
moraines4 ,in other instances shore     
ridges have been reported to end        
indefinitely and to be replaced at the  

same general horizon by glacial records 
of various character4 ,the correct      
interpretation of phenomena of this     
nature is especially important4         
,accurate measurements of the vertical  
intervals between well defined beaches  
at many localities would enable one to  
identify special horizons1 providing    
orographic movements were not in        
progress during the time the series was 
forming4 ,this method has recently been 
successfully applied on the north shore 
of ,lake ,superior1 where the character 
of the country does not admit of the    
tracing of individual terraces for      
considerable distances4  ,the deltas of 
tributary streams should also be        
revealed in the topography of the basin 
of an ancient water body4 ,changes in   
the character of lacustral sediments    
near where rivers emptied are also to be
 looked for4 ,sand dunes are frequently 
an important accompaniment of existing  
shores1 and their association1 perhaps1 
in a modified form1 with ancient beaches

 is to be expected4  #e4 ,fossils4 ,thus
 far only a few fossils have been found 
in the stratified clays and sands or in 
the ancient beaches of the ,laurentian  
basin4 ,such observations as have been  
made in this connection indicate an     
absence of the remains of marine life   
and the presence1 in a few instances1 of
 fresh-water shells in all of the basin 
west of the eastern border of the basin 
of ,lake ,ontario4 ,to the eastward of  
,lake ,ontario1 however1 in the ,st4    
,lawrence and ,champlain valleys1 marine
 fossils are common in deposits supposed
 to be contemporaneous with the         
stratified clays to the west4  ,a       
careful search in the clays and beaches 
left by the former water bodies might be
 rewarded by important discoveries4 ,in 
this examination microscopical organisms
 should not be neglected4 ,if after a   
detailed examination no fossils are     
discovered1 this negative evidence would
 have its value1 as it would indicate   
that the physical conditions were not   

favorable to life1 and an explanation   
for this fact might be found4 ,it is    
scarcely necessary to mention that care 
should be taken not to mistake the      
shells occurring in modern swamp        
deposits associated with the ancient    
beaches for true lacustral fossils4     
,about the borders of the present lakes 
and sometimes even below the level of   
the lowest of the ancient beaches the   
remains of the mastodon1 elephant1 giant
 beaver1 elk1 bison1 deer1 etc41 have   
been found4 ,the recency of the         
existence of such of these animals as   
are extinct may thus be established1 as 
well as the former distribution of those
 still living in other regions4         
,evidence of the existence of man has   
been reported from one of the old lake  
ridges in ,new ,york1 and it is         
important that this interesting         
discovery should be sustained by        
evidence from other localities4 ,stone  
implements especially should be looked  
for in undisturbed lacustral clays1 and 

in the gravels of the ancient beaches4  
,the remains of forests have been stated
 to occur in the lacustral clays        
adjacent to the south shore of ,lake    
,erie4 ,it is desirable to know the     
extent of these deposits and how        
continuous they are2 also the character 
of the plant remains they contain1 and  
whether they have been disturbed from   
the position in which they grew4 ,some  
of the questions that may be asked in   
this connection are3 ,was the basin     
drained and forest covered before the   
vegetable remains were buried1 or were  
the plants floated to their present     
position1 or did they grow on moraines  
covering the stagnant border of the     
retreating glacier and become involved  
and buried in morainal material as the  
ice melted8  #f4 ,life in the present   
lakes4 ,the fauna of the present lakes  
has a bearing on their past history1 for
 the reason that in the deeper parts of 
lakes ,superior and ,michigan           
crustaceans and fishes have been found  

which are believed to be identical with 
marine forms4 ,these may be considered  
as 8living fossils10 and are thought by 
some to indicate that the lakes in which
 they occur were formerly in direct     
communication with the ocean4 ,if the   
occurrence of living marine species in  
the present lakes is found to be widely 
at variance with the history of the     
basin as determined from physical       
evidence1 an inquiry should be made in  
reference to the manner in which the    
species discovered might migrate4  #g4  
,changes in elevation4 ,one of the most 
difficult problems in connection with   
the history of an inland region is the  
determination of changes of level4 ,by  
leveling along an ancient beach1        
post-lacustral changes in the relative  
elevations of various points may be     
readily ascertained4 ,pre-lacustral     
changes1 however1 by which ancient      
valleys have been obstructed1 are much  
more difficult of direct observation1   
but might appear from the study of the  

hard-rock topography1 as has already    
been suggested4 ,this branch of the     
investigation1 however1 should more     
properly begin at the coast and be      
extended inland4  #h4 ,former outlets4  
,several localities where the waters of 
the ,laurentian basin have overflowed   
during former high-water stages have    
been pointed out1 but some confusion has
 arisen in this connection1 for the     
reason that the channels formed by      
streams issuing from the margin of the  
ice during the closing stages of the    
,glacial epoch have1 in some instances1 
been mistaken for evidence of former    
lake outlets4 ,the old outlets which    
seem to have been well determined are   
situated at different levels1 and show  
that the entire basin could not have    
been occupied by a single great         
water-body1 unless1 as has been supposed
 by some1 it was in direct communication
 with the sea4 ,this hypothesis will be 
considered below4 ,it has sometimes been
 assumed that all of the basin below the

 level of some ancient outlet was once  
flooded1 so as to form a great lake in  
all of the basin now situated at a lower
 level2 but1 in making such             
generalizations1 the possibility of     
places in the rim of the basin being at 
a lower level than the outlet           
discovered1 thus necessitating a special
 explanation1 such as the partial       
occupation of the basin by glacial ice1 
or changes in elevation of such a       
character as to raise the locality of   
former overflow or to depress other     
regions1 have to be considered4  ,former
 outlets should bear a definite relation
 to neighboring shore lines and to      
sedimentary deposits4 ,the channels     
leading from former points of discharge 
merit examination1 as here again changes
 of level may perhaps be detected in the
 gradients of stream terraces4  ,most of
 the ancient outlets thus far recognized
 lead southward1 but as previously      
mentioned1 a former channel of discharge
 north of ,lake ,superior has recently  

been reported4 ,if this observation is  
confirmed1 it will have an important    
bearing on questions relating to changes
 of level and to the position of the ice
 front during the later stages in the   
retreat of the glaciers4  #i4 ,probable 
effects of a retreating ice sheet on    
drainage4 ,the generally accepted       
conclusion that glaciers advanced       
southward and occupied the ,laurentian  
basin during the ,glacial epoch and     
retreated northward toward the close of 
that epoch1 is sustained by a vast body 
of evidence4 ,as the ice sheet withdrew 
it left a superficial deposit frequently
 one or two hundred feet thick over     
nearly all of the region it abandoned1  
and pre-glacial drainage lines were     
obstructed and mostly obliterated4 ,as  
long as the slope in front of the ice   
was southward1 the drainage from it     
found ready means of escape1 but when   
the slope was northward towards the ice 
front1 the drainage was obstructed and  
lakes were formed4  ,we have good       

reasons for believing that the          
topography of the ,laurentian region was
 essentially the same at the close of   
the ,glacial epoch as it is now1 but the
 broader question of continental        
elevation is less definite4 ,the        
inequalities of the surface being       
essentially as we now find them1 it     
would follow that the first lake formed 
when the ice retreated to the north of  
the divide running through central ,ohio
 and central ,new ,york1 would be small 
and dependent on minor features in the  
relief of the land1 and would discharge 
southward4 ,as the ice retreated1 the   
lakes would expand and become united one
 with another and the larger lakes thus 
formed would still find outlet across   
the southern rim of the basin4 ,as the  
glaciers continued to retreat lower and 
lower1 passes would become free of ice  
and the lakes would be drained at lower 
levels1 old beaches would be abandoned1 
the lakes would contract1 and finally   
separate lakes would be formed in the   

lowest depression in the basins of the  
more ancient water bodies4 ,the shape of
 the retreating ice front would be      
determined by topographic conditions and
 would in turn determine the northern   
outline of the lakes along its margin4  
,this in brief is one hypothesis that   
has been proposed to explain the varied 
history recorded by the shore records1  
sediments1 etc41 within the basin4  #aj4
 ,communication with the sea4 ,another  
hypothesis which assumes to account for 
some of the facts observed1 is that the 
continent was depressed at the close of 
the ,glacial epoch sufficiently to allow
 the sea to have access to the          
,laurentian basin4 ,this hypothesis is  
coupled with others which do not        
recognize a period of ,pleistocene      
glaciation1 but1 as already suggested1  
this is a matter that is considered by  
the great body of ,american geologists  
as not being any longer open to         
profitable discussion4  ,in the study   
here outlined the question whether the  

water bodies which formerly occupied the
 ,laurentian basin were lakes or arms of
 the sea1 should not be difficult of    
direct and positive determination4 ,if  
fossils can be found within the basin1  
they might yield definite testimony1 but
 even if they are absent or if their    
evidence is inconclusive1 topography can
 be appealed to with the expectation of 
receiving a conclusive decision4  ,if   
the ,laurentian basin was occupied by an
 arm of the sea during various stages in
 the ,pleistocene elevation1 then the   
records of such a submergence should    
occur both within and without the       
depression1 and direct connection       
between the two should be expected4 ,if 
the waters within the basin were capable
 of making such well-defined shore      
records as are now found1 we are        
justified in assuming that the true     
ocean beach on the outer slopes of the  
basin would be still more conspicuous4  
,again1 the waters within the basin     
deposited a sheet of sediment1 certainly

 not less than one hundred feet thick2  
to be sure the conditions for rapid     
accumulation were there present1 but if 
the ocean covered the adjacent land it  
should have left similar deposits4 ,this
 is abundantly proven in the ,st4       
,lawrence and ,champlain valleys1 where 
clays containing marine fossils occur up
 to a certain horizon and record a      
,pleistocene invasion of these          
depressions by the sea4 ,if the adjacent
 ,ontario basin was occupied by the sea 
about the same time that the ,champlain 
valley received its filling of clays    
containing marine fossils1 there is     
every reason to believe that the        
deposits and their contained fossils in 
each basin would have been essentially  
the same4  ,one of the best known of the
 ancient shore lines about ,lake        
,ontario has an average elevation of    
approximately #ejj feet above the sea4  
,if the sea had access to the basin at  
the time this breech was formed1 then at
 corresponding horizon without the basin

 especially1 to the south and southeast1
 where the full force of the ,atlantic's
 waves would have been felt1 there      
should be still more prominent beaches4 
,many well-defined shore lines in the   
,laurentian basin are much higher than  
the one just referred to1 and if these  
were also formed during various stages  
of submergence1 as has been claimed1 it 
is evident that ocean beaches and ocean 
sediments of ,pleistocene age should be 
looked for over nearly the whole of the 
eastern part of the ,united ,states4    
,the student may easily answer this     
question for himself1 and thus perhaps  
make a contribution to the subject here 
treated4  ,in the investigation here    
outlined1 the work of previous observers
 should not be ignored1 and every       
plausible hypothesis that has been      
advanced to account for the facts       
observed should be carefully tested4 ,in
 writing these pages ,i have not quoted 
the writing of others1 for the reason   
that a discussion of evidence has not   

been the aim in view1 and also because  
the writings examined are so numerous   
that justice could not be done them in  
the space at command4 ,that the         
literature relating to the subject is   
voluminous is indicated by the fact that
 an annotated bibliography of the       
,pleistocene history of the ,laurentian 
basin1 now in preparation1 already      
contains over #bjj entries of individual
 papers4                      ,,israel  
,c4 ,,russell4   ,,footnotes     #eb    
,the ,topographic ,features of ,lake    
,shores1 by ,g4 ,k4 ,gilbert1 in        
,fifth ,ann4 ,rep4 ,u4 ,s4 ,geological  
,survey #ahhc-d4     #ec ,preliminary   
,paper on the ,terminal ,moraine of the 
,second ,glacial         ,epoch1 by ,t4 
,c4 ,chamberlin1 in ,third ,ann4 ,rep4  
,u4 ,s4 ,geological         ,survey1    
#ahha-b4     ,,editorials4   ,the       
,summer meeting of the ,geological      
,society of ,america will be held at    
,madison1 ,wis41 on ,august #ae and #af4
 ,the session of the ,american          

,association for the ,advancement of    
,science will begin at the same place on
 the #agth of ,august and extend to the 
#bc;d4 ,the ,congress of ,geologists1   
under the auspices of the ,columbian    
,exposition1 will begin at ,chicago1 on 
,august #bd1 and continue its sessions  
so long as its work may require4        
,preliminary to this series of meetings1
 ,professors ,m4 ,e4 ,wadsworth and ,c4 
,r4 ,van ,hise will meet such geologists
 as care to visit the ,lake ,superior   
region at the ,commercial ,hotel1 ,iron 
,mountain1 ,mich41 on the forenoon of   
,august #g1 and will act as guides      
during the week following4 ,a carefully 
prepared scheme for the trip is         
announced1 embracing visits to the      
leading points of interest in the       
,menominee1 ,marquette and ,gogebic iron
 districts1 and in the copper-bearing   
region of ,keweenaw ,point4 ,those who  
desire to participate in the excursion1 
or who wish information regarding it1   
should address ,professor ,van ,hise1 at

 ,madison4  ,in connection with the     
meetings of the ,geological ,society and
 the ,american ,association at ,madison1
 there will be excursions to the        
,devil's ,lake region1 to the ,dells of 
the ,wisconsin1 and to the driftless    
area1 under the guidance of geologists  
personally familiar with the features of
 most special interest4 ,the article of 
,professor ,van ,hise in this number is 
a timely presentation of some points of 
peculiar significance in the first named
 region1 and will prove very serviceable
 to those who choose the excursion to   
that region4  ,it is proposed to hold   
the sessions of the ,congress at        
,chicago at the ,art ,institute during  
the forenoons1 leaving the afternoons   
free for visiting the ,exposition4      
,experience has shown that a half day   
devoted to looking at exhibits1 where   
there is such a plethora of objects of  
interest as in the ,exposition1 taxes   
the faculties of observation to the full
 extent of their pleasurable employment4

 ,attendance upon the ,congress and the 
study of the ,exposition will1          
therefore1 it is thought1 constitute    
agreeable and profitable complements of 
each other4 ,excursions to points of    
geological interest in the vicinity of  
,chicago will be privately arranged1 if 
desired4  ,these three meetings1 with   
the attending excursions and the study  
of the ,exposition1 constitute a rare   
combination of opportunities which will 
doubtless be embraced very generally by 
the geologists of the country4          
,t4 ,c4 ,c4    99499  ,the supply of    
numbers one and two of this ,,journal   
remaining in the hands of the publishers
 has become reduced below the limit they
 desire to preserve for binding and for 
special purposes1 and they would esteem 
it a great favor on the part of those   
who may have received duplicates1 as    
sample copies or by the accidents of    
mailing while the lists were imperfect1 
if they would return such duplicates to 
them4 ,they will gladly return the      

postage if the address of the sender is 
placed on the wrapper4     ,,reviews4   
,,crystalline ,,rocks ,,from ,,the      
,,andes4    ,untersuchungen an          
altkrystallinen ,schiefergesteinen aus  
dem ,gebiete       der argentinischen   
,republik von ,b4 ,k,,hn4 ,neues        
,jahrbuch fr       ,min41 etc41 ,beit4  
,bd4 ,,vii41 #ahia1 p4 #bie4            
,untersuchung argentinischer ,pegmatite1
 etc41 von ,p4 ,,sabersky1 ib4       p4 
#cei4    ,untersuchungen an             
argentinischen ,graniten1 etc41 von ,j4 
,,romberg1       ib41 ,,viii41 #ahib1 p4
 #bge4  ,travelers and foreign residents
 in ,south ,america are rapidly         
furnishing information relative1 not    
only to the volcanic1 but also to the   
older crystalline rocks composing the   
great ,andes chain4 ,since the early    
observations of ,darwin1#ed the         
petrographical collections made by      
,stelzner during his three years'       
residence1 as professor1 at ,cordova    
7#ahgc-ahgf7 have been described by     

himself#ee and ,franke1#ef while the    
results of detailed studies of the more 
extensive collections gathered by       
,stelzner's successor1 ,professor ,l4   
,brackebusch1 are now beginning to      
appear4 ,professor ,brackebusch's       
residence in the ,argentine ,republic   
lasted from #ahgf till #ahhc1 and during
 this period he made numerous scientific
 expeditions4#eg ,the petrographical    
material thus obtained has been confided
 to specialists in ,germany for study4  
,three papers dealing with the          
crystalline schists 7gneisses71#eh      
pegmatites1#ei and granites1#fj have    
recently appeared4 ,the rocks of the    
granite contact-zones had been placed in
 ,professor ,lessen's hands before his  
death1 while communications on other    
special groups are doubtless to be      
expected4  ,these investigations        
naturally suffer from the forced absence
 of all field observations on the part  
of their authors1 but the purely        
petrographical study of the material    

brings to light many points of interest1
 while it furnishes the only sort of    
detailed information regarding the rocks
 of these remote regions which we can   
for the present hope for4 ,it is here   
desired only to direct attention to a   
few of the most striking results        
obtained from the ,brackebusch material 
by the three authors last cited4  ,dr4  
,khn's paper on the crystalline schists 
treats principally of gneiss1 and offers
 little that is new4 ,it is mostly      
occupied with additional evidence of    
structural and chemical changes due to  
dynamic metamorphism in the sense of    
,lehmann4 ,the most noteworthy of these 
are development and microstructure of   
fibrolite2 production of augen-gneiss   
from porphyritic granite2 development of
 microcline structure in orthoclase by  
pressure2 secondary origin of           
microcline1 microperthite and           
micropegmatite2 alteration of garnet to 
biotite and hornblende4  ,dr4           
,sabersky's paper on the coarse-grained 

granites or pegmatites is entirely      
mineralogical1 and is devoted           
principally to elucidating the structure
 of microcline4 ,the author concludes   
that the well-known gridiron structure  
is due1 not to two twinning laws 7the   
,albite and ,pericline71 as has been    
generally supposed1 but to the ,albite  
law alone1 in accordance with which the 
individuals form both contact and       
penetration twins1 like the albite      
crystals from ,roc-tourn1 described by  
,g4 ,rose4  ,dr4 ,romberg's paper on the
 ,argentine granites is much more       
extensive than the two preceding4 ,it is
 embellished by seventy-two             
microphotographs1 many of which         
admirably illustrate the special points 
described4 ,he comes to several results 
of great petrographical significance1   
the most important of which relate to   
the origin of quartz-feldspar           
intergrowths in granitic rocks4 ,he     
clearly shows that beside the original  
granite quartz there is also much of a  

secondary nature present4 ,this is not  
microscopically distinguishable from the
 original mineral1 but its later genesis
 is demonstrated by many careful        
observations on its relation to other   
constituents4 ,the abundant secondary   
quartz is regarded as the product of    
weathering--principally of the feldspar1
 into which it has a peculiar tendency  
to penetrate4 ,the extreme sensitiveness
 of quartz to pressure is emphasized 7as
 it has been by ,lehmann and the present
 writer7 and illustrated by undulatory  
extinction1 banding1 granulation and    
even plastic bending around other       
minerals4 ,dynamic action is regarded as
 the efficient cause of the secondary   
impregnation of feldspar by quartz1 and 
a union of this with weathering of the  
feldspar as the source of the abundant  
and complex pegmatitic intergrowths of  
quartz and feldspar4  ,these results are
 important1 and they will now doubtless 
come to be generally recognized4 ,it is1
 however1 of interest to observe in this

 connection that all which is here      
announced as new in regard to secondary 
and 8corrosion0 quartz was described and
 figured in even greater detail by      
,prof4 ,r4 ,d4 ,irving ten years ago4   
,this does not appear to be known to    
,dr4 ,romberg1 for he does not allude to
 it1 but anyone who will turn to pages  
#ii to #abd and plates ,,xiii1 ,,xiv and
 ,,xv of the monograph on the ,lake     
,superior ,copper ,rocks 7vol4 #e1 ,u4  
,s4 ,geol4 ,survey1 ,washington1 #ahhc7 
will find his conclusions stated in     
almost the same language and with a much
 wider range of fact and illustration4  
,dynamic action is not here adduced as a
 cause for the saturation of feldspar by
 secondary micropegmatitic quartz1 since
 the ,lake ,superior rocks show no      
evidence of having been subjected to    
pressure1 but that the quartz itself has
 been derived from the leaching of the  
feldspar substance and that the         
impregnation is mostly confined to the  
orthoclase is clearly stated4  ,dr4     

,romberg also demonstrates1 in a number 
of cases1 the secondary origin of       
albite1 especially as microperthite1 and
 of microcline4 ,he gives details       
relating to each of the mineral         
constituents1 and then the effects of   
pressure and of chemical action on the  
most important of them4 ,among many     
interesting observations but a few can  
be even mentioned here2 such1 for       
instance1 as the original character of  
muscovite in many granites2 the         
alteration of garnet into muscovite2 the
 dependence of the well-known pleochroic
 halos in biotite and cordierite upon   
the substance of the zircon which they  
almost invariably surround1 and         
secondary rutile needles which grow out 
from biotite into both quartz and       
feldspar4 ,in one rock occurring in a   
granite a violet1 strongly pleochroic   
mineral was found1 which1 in neither    
composition nor physical properties1    
agreed exactly with any known species4  
,it seems to be intermediate between    

andalusite and dumortierite1 but1 as its
 individuality is not yet perfectly     
established1 no new name is proposed for
 it4                      ,g4 ,h4       
,,williams4     ,the ,mineral ,industry1
 its ,statistics1 ,technology and       
,trade1 in the       ,united ,states and
 ,other ,countries1 from the ,earliest  
,times to the       ,end of #ahib4 ,vol4
 ,i4 ,edited by ,,richard ,p4           
,,rothwell1 editor of       the         
,engineering and ,mining ,journal4 #fbi 
pp41 #hvo4  ,this volume is a           
statistical supplement of the           
,engineering and ,mining ,journal1 and  
is published by the ,scientific         
,publishing ,co41 of ,new ,york1 #ahic4 
,it takes the place of the former annual
 statistical number of the ,engineering 
and ,mining ,journal1 and it is the     
first volume of a series which is to be 
issued annually4 ,the object of the     
present volume is to make known1 as soon
 as possible after the expiration of the
 year #ahib1 the statistics and the     

various conditions of the mining        
industry in that year and in previous   
years4 ,the future volumes will1 each   
year1 bring these statistics up to date1
 and thus the full particulars of the   
mining industry will be known within a  
few days of the expiration of every     
year4 ,the volume is a compilation of   
articles written by different authors1  
and the names of these writers are      
guarantee that the different subjects   
have been treated by authorities in the 
departments with which they deal4 ,the  
editor himself1 it is but justice to him
 to state1 has written some of the most 
important parts of the volume1 notably  
the article on the statistics of gold   
and silver1 and his well-known          
familiarity with the subjects he        
discusses renders the reader confident  
of their accuracy4  ,the present volume 
is not confined to the bare presentation
 of figures of production and           
consumption of various mineral products1
 but it treats each individual branch of

 the mining industry in its various     
departments2 and in this way the volume 
really represents a series of treatises 
on the various mining products and the  
methods of treating them4 ,the          
production of each material is given not
 only for the ,united ,states but also  
for foreign countries2 the conditions of
 the ,american and foreign markets      
during #ahib and previous years are     
discussed1 while the various uses of the
 different materials1 the history of    
mining in different districts1 the means
 of transportation1 the metallurgical   
methods of treating different ores1 the 
methods of sampling1 and the            
possibilities of competition in various 
mining industries are also described4   
,in addition to this1 tables of         
assessments levied and dividends paid by
 various mining companies are given4    
,the volume ends with a concise         
statement of the statistics and         
condition1 as well as the extent1 of the
 mining industries of foreign countries4

 ,thus there is presented1 in a volume  
of no excessive size1 a complete and    
concise epitome of the mining industries
 of the world2 and this work was        
completed almost immediately after the  
time to which it relates4  ,the various 
subjects are treated in the following   
order3 ,a rsum and tables of statistics 
of the mineral products of the ,united  
,states2 articles on ,aluminum1         
,antimony1 ,asbestos1 ,asphaltum1       
,barytes1 ,bauxite1 ,borax1 ,bromine1   
,cement1 ,chemical ,industry1 ,chromium1
 ,coal and ,coke1 ,copper1 ,corundum and
 ,emery1 ,cryolite1 ,feldspar1          
,fluorspar1 ,gold and ,silver1 ,iron and
 ,steel1 ,lead1 ,manganese1 ,mica1      
,nickel and ,cobalt1 ,onyx1 ,petroleum1 
,phosphate ,rock1 ,platinum ,group of   
,metals1 ,plumbago1 ,precious ,stones1  
,pyrites1 ,quicksilver1 ,salt1 ,soda1   
,sulphur1 ,talc1 ,tin1 ,whetstones and  
,novaculite1 ,zinc2 ,tables of          
,assessments ,levied by ,mining         
,companies from #ahhg-ahic2 ,tables of  

,dividends ,paid by ,american ,mining   
,companies2 ,baltimore ,mining ,stock   
,market1 ,boston ,mining ,stock ,market1
 ,denver ,mining ,stock ,market1 ,london
 ,mining ,stock ,market1 ,lake ,superior
 ,mining ,stock ,market1 ,new ,york     
,mining ,stock ,market1 ,paris ,mining  
,stock ,market1 ,pittsburg ,mining      
,stock ,market1 ,salt ,lake ,city       
,mining ,stock ,market in #ahib1 ,san   
,francisco ,mining ,stock ,market2      
,foreign ,countries--,austria-,hungary1 
,belgium1 ,canada1 ,china1 ,france1     
,germany1 ,italy1 ,japan1 ,russia1      
,south ,american ,countries1 ,spain and 
,cuba1 ,sweden1 ,united ,kingdom of     
,great ,britain and ,ireland4  ,the     
importance of the subject treated in    
this volume can be appreciated when it  
is known that the products of the mines 
of the ,united ,states alone in the     
census year of #ahhi amounted to        
#ehg1bcj1ffb1 and that this amount      
really only represents the interest on  
an immensely larger capital invested4   

,the mining products of the ,united     
,states are far more important in their 
aggregate value than those of any other 
country in the world1 though1 in many   
individual products1 other countries    
supply more than the ,united ,states4   
,this country is first1 however1 in the 
production of pig iron and steel4 ,it is
 also first in the production of copper1
 gold1 silver1 petroleum1 and a number  
of other products4 ,great ,britain is   
still the leader in the production of   
coal1 but the ,united ,states'          
production is rapidly growing and       
already equals #ha4jh of the ,british   
production1 and supplies #bh4ge of the  
world's consumption4  ,every subject in 
this volume is fully discussed1 and at  
the same time nothing is given which is 
not appropriate and even necessary4     
,thus a combination of completeness and 
conciseness is reached which is         
excellent4 ,among the most carefully and
 exhaustively treated subjects are      
copper1 gold and silver1 the platinum   

group of metals and coal and iron1      
though many others might be mentioned1  
for every subject undertaken has been   
thoroughly treated4 ,in the article on  
copper the statistics of production and 
consumption1 as well as the condition of
 the various domestic and foreign       
markets1 are fully discussed by the     
editor1 and1 in addition1 separate      
articles are also given on 8,american   
,methods of ,ore ,sampling and          
,assaying10 by ,albert ,r4 ,ledoux1 and 
on 8,bessemerizing ,copper ,matte10 by  
,charles ,wade ,stickney4 ,the article  
on the statistics of gold and silver is 
by ,mr4 ,r4 ,p4 ,rothwell1 editor of the
 volume1 and is an excellent piece of   
statistical work1 giving1 as it does1   
the statistics of production of gold and
 silver in the world for a number of    
years back4 ,to this article are        
appended interesting papers on the      
8,chronology of the ,gold and ,silver   
,industry1 #adib-ahib10 by ,walker      
,renton ,ingalls1 on 8,recent           

,improvements in ,gold ,chlorination10  
by ,john ,e4 ,rothwell1 and on the      
8,cyanide ,process10 by ,louis ,janin1  
,jr4  ,the article on the ,platinum     
,group of ,metals1 by ,charles ,bullman1
 gives complete information regarding   
the production1 consumption1 nature of  
the deposits1 metallurgy and uses of    
platinum and its related metals1        
iridium1 rhodium1 osmium1 palladium and 
ruthenium4 ,the articles on ,coal and   
,coke and on ,iron and ,steel1 both by  
,mr4 ,wm4 ,b4 ,phillips1 give full      
statistics of production and            
consumption1 as well as interesting     
historical data1 and reports of the     
condition of various markets4 ,many of  
the other articles in this volume       
deserve mention1 but lack of space      
forbids further detail4 ,it may be said1
 however1 that everything necessary is  
presented1 and nothing unnecessary or   
unreliable is given2 in other words1 the
 volume contains no trash4  ,one of the 
most noticeable features of the volume  

is the uniform and systematic manner in 
which the results are presented4 ,the   
uniform arrangement of statistics is a  
matter requiring the greatest labor and 
statistical ability4 ,compiling a single
 table of statistics is a simple matter1
 but arranging a vast mass of           
statistics1 relating to many diverse    
subjects1 on a uniform and intelligible 
basis1 is entirely another matter1 and  
requires the highest skill of the       
statistician4 ,in the ,mineral ,industry
 this has been accomplished in a most   
successful manner2 everything is clear  
and intelligible at the first glance1   
and everything is in its proper place4  
,a great detriment to the systematic    
presentation of statistics has been1 as 
pointed out by the editor1 the necessity
 of using our present system of weights 
and measures1 with 8our long and short  
tons1 our barrels of #bjj1 #bhj1 #cjj or
 #djj lbs1 our pounds avoirdupois and   
our pounds ,troy1 our bushels of a dozen
 different weights1 and our gallons of  

several incomprehensible kinds02 but the
 disadvantages of this system have been 
partly avoided in many cases by giving  
the statistics in metric measures as    
well as in our own4  ,the question of   
the cost of production has been given   
especial prominence in this volume1 with
 a view to showing the reduction in the 
cost of the crude products4 ,to use the 
words of the editor3 8,the itemization  
of cost is the first essential step in  
securing economy in producing any       
article1 and the history of every       
country and of every industry has shown 
that prosperity1 whether national1      
industrial1 or individual1 is1 in a     
general way1 inversely proportional to  
the cost of supplying the rest of the   
world with what one produces40 ,these   
reductions are in no way dependent on   
the reduction of wages4 ,on the         
contrary1 many of the mining industries 
where the greatest reduction in cost of 
production has been accomplished1 are   
carried on with high priced labor2 and  

in many other cases1 where the wages are
 not high1 the condition of the         
wage-earners has been greatly improved4 
,the reduction in cost of production has
 been entirely brought about by         
improvements in mining machinery1 by a  
more thorough understanding of the      
nature of the deposits to be worked1 and
 by more intelligent management and     
labor4 ,the reduction in cost of        
production is nowhere better seen than  
in the materials most necessary to our  
welfare4 ,for instance1 coal can in some
 cases be carried by rail for #djj miles
 and delivered on board vessels for from
 #b to #b4be per ton1 and yet the mine  
owners and railroads make dividends2    
some of the manufacturing establishments
 in ,western ,pennsylvania obtain coal  
at from #fj to #ge cents per ton at     
their works2 hard gold-bearing quartz   
can be crushed1 washed and #ie per cent4
 of the gold saved on the plates for    
#a4be per ton2 high grade ,bessemer iron
 ore can be mined1 handled1 shipped and 

delivered a thousand miles from the     
point of production for less than #d4jj 
per ton4 ,all these figures seem almost 
incredible until one investigates the   
various devices which the ingenuity and 
better education of those engaged in the
 industry have invented for reducing the
 expenses of production4  ,the former   
annual statistical numbers of the       
,engineering and ,mining ,journal were  
excellent in all they undertook1 but the
 present volume1 the ,mineral ,industry1
 makes a great advance in giving the    
statistics for foreign countries in     
addition to those of the ,united        
,states4 ,by so doing it gives the      
,american producers an opportunity to   
know the present1 past and probable     
future conditions of competition in     
foreign countries4  ,the two most       
important features in any statistical   
work are accuracy and promptness4 ,the  
necessity of accuracy is self-evident1  
and without promptness the statistics   
lose much of their serviceability to    

those most interested in them1 for the  
statistics of an industry published a   
year or two years late are rarely of    
much value to those engaged in that     
industry4 ,the business man wants his   
statistics immediately after the        
expiration of the time to which they    
relate1 so that he may know the existing
 condition of the industry in which he  
is engaged2 but if he does not get these
 statistics until many months or even   
several years afterwards1 the condition 
of the industry may have changed        
entirely since the time to which the    
statistics refer4 ,it is the promptness 
with which this volume is issued1       
combined with a high degree of accuracy1
 far greater than would be expected in  
statistics so hastily compiled1 that    
gives it its especial value4  ,in       
conclusion1 it may be said1 that as a   
piece of statistical work1 relating to  
an industry that is world-wide in its   
scope1 combining accuracy with full     
detail and systematic arrangement1 and  

issued so soon after the close of the   
time to which it relates1 the ,mineral  
,industry has never been equaled in this
 country or abroad4 ,the former         
statistical numbers of the ,engineering 
and ,mining ,journal1 which referred    
mostly only to ,american mining1 were   
considered remarkable pieces of         
statistical work1 on account of the     
promptness of their publication2 but in 
the ,mineral ,industry we have an       
epitome of the mining operations of     
every quarter of the globe1 published   
almost immediately after the close of   
the time to which they refer1 a feat    
which heretofore would have been        
declared impossible4 ,this              
accomplishment is most creditable to the
 editor1 ,mr4 ,rothwell1 to the         
systematic organization of the          
,scientific ,publishing ,co41 and to the
 business manager1 ,mrs4 ,braeunlich1 by
 whose business ability such an         
expensive undertaking is made           
commercially practicable4 ,the volume   

will be found of the greatest value to  
the economic geologist1 the miner1 the  
engineer and the business man4          
,r4 ,a4 ,f4 ,,penrose1 ,,jr4            
,,footnotes     #ed ,geological         
,observations in ,south ,america1 #ahdf4
     #ee ,beitrge zur ,geologie und     
,paleontologie der argentinischen       
,republik2 ,i4 ,geologischer ,theil1    
#ahhe4     #ef ,studien ber             
,cordillerengesteine4 ,apolda1 #ahge4   
#eg ,reisen in den ,cordilleren der     
argentinischen ,republik1 ,verh4        
der ,gesellsch4 fr ,erdkunde4 ,berlin1  
#ahia4     #eh ,untersuchungen an       
altkrystallinen ,schiefergestenien aus  
dem         ,gebiete der argentinischen 
,republik1 von ,b4 ,khn4 ,neues         
,jahrbuch fr ,min41 etc41 ,beit4 ,bd4   
,,vii41 #ahia1 p4 #bie4     #ei         
,untersuchung argentinischer ,pegmatite1
 etc41 von ,p4 ,sabersky1         ib41  
p4 #cei4     #fj ,untersuchungen an     
argentinischen ,graniten1 etc41 von ,j4 
,romberg1 ib41 ,,viii41 pp4             

,,analytical ,,abstracts ,,of ,,current 
,,literature4#fa     ,a ,new            
,tniopteroid ,fern and its ,allies4 ,by 
,,david ,,white4 7,bulletin             
,geological ,society of ,america1 #d    
pp41 #aai-abb1 pl4 ,i474  ,mr4 ,white   
has described1 under the name of        
,tniopteris missouriensis1 a new and    
well characterized fern from the ,lower 
,coal-measures in the vicinity of       
,clinton1 ,henry ,county1 ,missouri4    
,botanically1 it is of particular       
interest in that it combines the        
so-called tniopteroid and alethopteroid 
types of structure1 while geologically  
it is of much value in supplying a      
readily identified stratigraphic mark in
 a part of the ,carboniferous not       
especially rich in fossil plants4 ,after
 thoroughly describing it and           
considering its specific and generic    
resemblances1 the author discusses at   
length its suggested genetic relations  
and represents in a graphic manner a    
scheme of its probable ancestors and    

line of descent4                        
,f4 ,h4 ,k4         99       99       99
       99       99    ,rainfall ,types  
of the ,united ,states4 ,annual ,report 
by       ,vice-,president ,,general ,a4 
,w4 ,,greely4 7,the ,national           
,geographic       ,magazine4 ,vol4 ,v41 
,april #bi1 #ahic1 pp4 #de-eh pl4 #bj74 
,the paper confines itself to the       
characteristic distribution of          
precipitation throughout the year and   
gives the rainfall types of the country4
  7a7 ,the best defined type of rainfall
 within the ,united ,states is that     
which dominates the ,pacific coast      
region as far east as western ,utah4    
,the characteristic features are a very 
heavy precipitation during midwinter1   
and an almost total absence of rain     
during the late summer4 7b7 ,the        
characteristics of the ,mexican type1   
dominating ,mexico1 ,new ,mexico and    
western ,texas1 are a very heavy        
precipitation after the summer solstice 
and a very dry period after the vernal  

equinox4 ,august is the month of        
greatest rainfall1 while ,february1     
,march and ,april are almost free from  
precipitation4 7c7 ,the ,missouri type  
covers the greatest area1 dominating the
 watersheds of the ,arkansas1 ,missouri 
and upper ,mississippi rivers1 and of   
lakes ,ontario and ,michigan4 ,it is    
marked by a very light winter           
precipitation1 followed in late spring  
and early summer by the major portion of
 the yearly rain1 the period when it is 
most beneficial to the growing grain4   
7d7 ,the ,tennessee type1 prevailing in 
,kentucky1 ,tennessee1 ,arkansas1       
,mississippi and ,alabama1 has the      
highest rainfall the last of winter1    
while the minimum is in mid-autumn4 7e7 
,the ,atlantic type1 covering all the   
coast save ,new ,england1 is one where  
the distribution throughout the year is 
nearly uniform1 with a maximum          
precipitation after the summer solstice1
 and a minimum during mid-autumn4 7f7   
,the ,st4 ,lawrence type is             

characterized by scarcity during the    
spring months1 heavy rainfall during the
 late summer and late autumn months1    
with a maximum during ,november4  ,the  
regions lying between these several     
type-regions have composite rainfall    
types1 resulting from the influence of  
two or more simple types4               
,h4 ,b4 ,k4         99       99       99
       99       99    ,the ,geographic  
,development of the ,eastern ,part of   
the ,mississippi       ,drainage        
,system4 ,by ,,lewis ,g4 ,,westgate1    
,middletown1 ,conn4       7,american    
,geologist1 ,vol4 ,,xi1 ,april1 #ahic1  
#ae pp47  ,the drainage of the ,eastern 
,mississippi basin in post-carboniferous
 was in all probability consequent upon 
the tilting which accompanied the       
stronger folds of the ,appalachian      
revolution in the east4 ,the present    
drainage is found to accord in the main 
with this hypothetical                  
post-carboniferous drainage1 but several
 streams depart quite widely from it4   

7a7 ,the great drainage lines of the    
,st4 ,lawrence basin are structural     
valleys developed along the strike of   
the softer ,paleozoic strata1 and at    
right angles to the original surface4   
,the streams seem1 therefore1 to have   
adjusted themselves to the differences  
in hardness and structure of the beds   
discovered4 7b7 ,the ,ohio and          
,cumberland rivers cut directly across  
the ,tennessee and ,cincinnati          
anticlines4 ,the most probable          
explanation is that the rivers were     
superimposed upon the arched and eroded 
,silurian rocks from a thin cover of    
carboniferous beds--now entirely        
removed4 7c7 ,the ,upper ,mississippi   
does not follow the dip of the rocks to 
the southwest1 but follows the strike to
 the southeast4 ,this part of the river 
probably dates from the elevation of the
 plains on the west and the             
,appalachians on the east1 which marked 
the close of the ,cretaceous and which  
left a broad north and south valley4 7d7

 ,the author finds good reason to       
believe that the ,lower ,mississippi1 in
 post-carboniferous times1 flowed west  
through ,missouri and ,arkansas4 ,the   
present course was probably taken at the
 close of the ,cretaceous in consequence
 of elevations on the west and east1 and
 possible depression in the south4  ,the
 ,cretaceous base-level recognized by   
,davis on the ,atlantic slope can be    
traced more or less discontinuously1 and
 remnants of it are believed to exist in
 ,kentucky1 ,tennessee1 ,wisconsin1     
,minnesota and ,arkansas4 ,but in       
general the work of the ,tertiary cycle 
has obliterated almost all evidence of  
it on all but the hard sandstones and   
conglomerates of the ,paleozoic series4 
,good examples of the lowlands excavated
 from the ,cretaceous base-level during 
the ,tertiary cycle1 are the ,valley of 
the ,east ,tennessee and the central    
lowland of ,kentucky and ,tennessee4    
,during the post-,tertiary sub-cycle the
 larger streams trenched to greater or  

less extent these lowlands4 ,no attempt 
is made to carry the history of the     
development of the ,mississippi1        
drainage into the complicated chapter of
 the ice-invasion4                      
,h4 ,b4 ,k4         99       99       99
       99       99    ,on a ,new ,order 
of ,gigantic ,fossils4 ,by ,,erwin ,h4  
,,barbour4 7,university       ,studies4 
,published by the ,university of        
,nebraska4 ,vol4 ,i1 ,no4 #d1           
,july1 #ahib1 pp4 #bc1 pl4 #e74  ,a part
 of ,sioux ,county1 ,nebraska1 lying    
north of the ,niobrara ,river1 has      
yielded a new order of gigantic ,miocene
 fossils unlike anything heretofore     
known4 ,they are best described as      
fossil corkscrews1 of great size1       
coiling in right-handed or left-handed  
curves about an actual axis or around an
 imaginary axis4 ,the screws are often  
attached at the bottom to an immense    
transverse piece1 rhizome1 underground  
stem1 or whatever it may be1 which is   
sometimes three feet in diameter4 ,in   

other cases the corkscrew ends abruptly 
downward1 as it always does upwards4 ,in
 still other cases the transverse piece 
is variously modified1 and sometimes    
blends into the sandstone matrix1 as if 
the underground stem1 while growing at  
one end1 was decaying at the other4 ,the
 fossil corkscrew is invariably         
vertical1 and the so-called rhizome     
invariably curves rapidly upwards1 and  
extends outwards an indefinite distance4
  ,that they could ever have been formed
 by burrowing animals1 by geysers or    
springs1 or by any mechanical means     
whatever1 is entirely untenable4 ,their 
organic origin is unquestionable4       
,microscopic sections show smooth       
spindle-shaped rods1 which are          
suggestive of sponge spicules4 ,from the
 numbers seen in place it is evident    
that they flourished in thickly crowded 
forests of vast extent4  ,a finely      
preserved rodent's skeleton was found in
 one great stem4 ,the probable          
explanation is not that the rodent      

burrowed there1 but that its submerged  
skeleton became an anchorage for a      
living1 growing ,daimonelix1 which      
eventually enveloped it4  ,the author   
proposes this provisional               
classification3    ,order4      ,family4
         ,genus4        ,species4       
,daimonelicid4  ,daimonelix4            
circumaxilis                            
bispiralis   ------  --------------     
-----------  anaxilis                   
robusta                                 
carinata4                               
-----------  ------                     
-----------  ------  ,the different     
species are described in full4          
,h4 ,b4 ,k4         99       99       99
       99       99    ,the ,vertical    
,relief of the ,globe4 ,by ,,hugh       
,,robert ,,mill1 ,d4,sc41               
,f4,r4,s4,e4 ,scottish ,geographical    
,magazine1 ,april1 #ahij4  ,the purpose 
of ,dr4 ,mill's paper is to show a      
simple yet adequate basis on which to   
build the superstructure of physical    

geography4 ,it does not attempt a       
discussion of the distribution and      
varieties of vertical relief4 ,the      
structure of the earth is stated most   
simply by describing it as an irregular 
stony ball1 covered with an ocean and an
 envelope of air4 ,if the lithosphere   
were perfectly smooth and at rest1 with 
the hydrosphere uniformly spread over   
its surface1 the former would have the  
form of the terrestrial spheroid1 and   
the latter would surround it to a depth 
of #a4g miles4 ,the surface of this     
hypothetical spheroid ,dr4 ,mill calls  
mean sphere level4 ,of course1 in       
reality the surface of the lithosphere  
is not perfectly smooth4 ,parts of it   
are greatly depressed and parts much    
elevated1 the latter forming the land of
 the earth4 ,the writer proceeds to     
calculate the position of mean sphere   
level1 and in the absence of accurate   
data he uses the careful estimates of   
,dr4 ,john ,murray1 which are as        
follows3 ,average depths of oceans      

#b4cf miles2 average height of land     
4#dbf miles2 average thickness of       
hydrosphere surrounding smoothed        
lithosphere  #a4g mile2 area of land    
#ee1jjj1jjj square miles2 area of oceans
  #ada1gjj1jjj square miles4 ,suppose a 
block of #ee1jjj1jjj of square miles    
area and #a4g miles deep to be cut out  
of the smoothed lithosphere and set down
 on the surface alongside the           
depression4 ,no change will take place  
in the surface of the hydrosphere4 ,if  
the surface of the #ada1gjj1jjj square  
miles of lithosphere were reduced to    
uniformity1 the whole depressed area    
would lie 4#ff mile beneath mean sphere 
level1 and the depth of the ocean       
becomes #b4cf miles4 ,to raise the land 
to its actual mean level above the      
hydrosphere surface1 a sufficient       
quantity of matter must be removed from 
the depressed area and placed on the    
elevated block4 ,let x  the thickness of
 the belt removed and y equal the       
thickness of the belt when placed on the

 elevated block4 ,then x  y is the      
height of the land above the actual     
hydrosphere level4 ,from the data given 
the following equations are easily      
obtained3          x  y - 4#dbf         
#j   #ada4g x       -   #ee y      #j   
x        4#ab and y  4#cjf in miles4    
,the average height of the land above   
mean sphere level is thus #a4g  4#cjf   
#b4jjf miles1 and the average depth of  
the depressed portion beneath mean      
sphere level is 4#ff  4#ab  4#gh mile4  
,dr4 ,mill divides the earth into the   
three following divisions3 7#a7 ,abysmal
 area1 occupying all the depressions    
beneath the mean surface of the         
lithosphere1 occupying #ej per cent4 of 
the earth's surface2 7#b7 ,transitional 
area1 comprising all the regions above  
mean sphere level covered by the        
hydrosphere1 occupying #bb per cent4 of 
the surface2 7#c7 ,continental area1 all
 the lithosphere that projects above the
 hydrosphere1 or #bh per cent4 of the   
earth's surface4                        

,j4 ,a4 ,b4   ,,footnote     #fa        
,abstracts in this number are prepared  
by ,f4 ,h4 ,knowlton1 ,henry ,b4        
,kummel1 ,j4 ,a4 ,bownocker4            
,,acknowledgments4   ,the following     
papers have been donated to the library 
of the ,geological ,department of the   
,university of ,chicago3  ,,abbott1     
,,charles ,c41 ,m4,d4      --,recent    
,archological ,explorations in the      
,valley of the ,delaware4     #cj pp41  
#a pl4--,publications of the ,university
 of ,pennsylvania4     ,series in       
,philology1 ,literature and ,archology1 
,vol4 ,,ii1 ,no4 #a4  ,,adams1 ,,frank  
,d4      --,on ,some ,granites from     
,british ,columbia and the ,adjacent    
,parts of     ,alaska and the ,yukon    
,district4 #ad pp41 ,ill4--,canadian    
,record of     ,science1 ,sept4 #ahia4  
--,notes to ,accompany a ,tabulation of 
the ,igneous ,rocks based on the        
,system of ,professor ,h4 ,rosenbusch4  
#f pp41 #a pl4--,canadian ,record of    
,science1 ,dec4 #ahia4      --,on the   

,geology of the ,st4 ,clair ,tunnel4 #h 
pp41 #a pl4--,trans4 ,roy4     ,soc4    
,canada1 ,section ,,iv1 #ahia4          
--,on the ,presence of ,chlorine in     
,scapolites4 #e pp4--,am4 ,jour4        
,science1 ,apr4 #ahgi4      --,notes on 
the ,lithological ,character of some of 
the ,rocks     ,collected in the ,yukon 
,district and ,adjacent ,northern       
,portion of     ,british ,columbia4 #f  
pp4--,annual ,report1 ,geol4 ,sur4 of   
,canada1 #ahhg4      --,on ,some        
,canadian ,rocks ,containing ,scapolite1
 with a ,few ,notes on     ,some ,rocks 
,associated with the ,apatite ,deposits4
 #af pp4--,canadian     ,record of      
,science1 ,oct4 #ahhh4      --,on the   
,microscopical ,character of the ,ore of
 the ,treadwell ,mines1     ,alaska4 #e 
pp41 ,ill4--,read before the ,royal     
,soc4 ,canada1 ,may1 #ahhi4      --,on a
 ,melilite-,bearing ,rock 7,alnoite7    
from ,ste4 ,anne de ,bellevue1     near 
,montreal1 ,canada4 #aj pp41 ,ill4--,am4
 ,jour4 ,sci41 ,vol4 ,,xliii1     ,apr4 

#ahib4  ,,ami1 ,,henry ,m41 ,m4,a41     
,f4,g4,s4      --,the ,utica ,terrane in
 ,canada4 #cb pp4--,canadian ,record of 
,science1     ,oct4 #ahib4              
--,additional ,notes on the ,geology and
 ,palontology of ,ottawa and     its    
,environs4 #aa pp4--,ottawa ,naturalist1
 ,sept4 #ahib4      --,catalogue of     
,silurian ,fossils from ,arisaig1 ,nova 
,scotia4 #g     pp4--,from the ,nova    
,scotian ,inst4 of ,sci41 ,ser4 #b1     
,vol4 ,i1 #ahib4  ,,andreae1 ,a4        
--,ueber die ,nachahmung verschiedener  
,geysirtypen und ber     ,gasgeysire4 #f
 pp4--,gesammt-,sitzung vom #ac ,jan4   
#ahic4  ,,bayley1 ,w4 ,s4      --,a     
,summary of ,progress in ,mineralogy and
 ,petrography in     #ahib4--;,american 
,naturalist4  ,,becker1 ,,george ,f4    
--,finite ,homogeneous ,strain1 ,flow   
and ,rupture of ,rocks4 #gg             
pp4--,bull4 ,geol4 ,soc4 ,am41 ,jan4    
#ahic4  ,,beecher1 ,c4 ,e4              
--,notice of a ,new ,lower ,oriskany    
,fauna in ,columbia ,co41 ,n4 ,y4 #d    

pp4--,am4 ,jour4 ,sci41 ,vol4 ,,xliv1   
,nov4 #ahib4  ,,branner1 ,j4 ,c4        
--,annual ,reports of the ,arkansas     
,geological ,survey1 #ahhh1 ,vols4 #a1  
#b1 #c1 #d2 #ahhi1 ,vol4 #b2 #ahij1     
,vols4 #b and #c4  ,,bryce1 ,,george1   
,,ll4,d4      --,older ,geology of the  
,red ,river and ,assiniboine ,valleys   
with an     ,appendix4 #g pp41 ,ill4    
,read before the ,historical and        
,scientific     ,society of ,manitoba1  
,nov4 #ahia4  ,,broadhead1 ,g4 ,c4      
--,a ,bibliography of the ,geology of   
,missouri1 by ,f4 ,a4 ,samson4 #agh     
pp4      --,report of the ,geological   
,survey of the ,state of ,missouri1     
including ,field ,work of #ahgc-d1 with 
#ia illustrations and an atlas4     #ghh
 pp4      --,preliminary ,report on the 
,coal ,deposits of ,missouri from ,field
     ,work prosecuted during the years  
#ahij-ia1 by ,arthur ,winslow1 ,state   
,geologist4 #bbj pp4 #a pl41 #aca       
,illustrations4  ,,carter1 ,,oscar1 ,c4 
,s4      --,artesian ,wells as a ,water 

,supply for ,philadelphia4 #d           
pp4--,proc4     of the ,chem4 ,section  
of the ,franklin ,inst41 ,jan4 #ahic4   
,,chamberlin1 ,t4 ,c4      --,the       
,requisite and ,qualifying ,conditions  
of ,artesian ,wells4 #db pp4     #a pl4 
,extract1 ,fifth ,annual ,report of the 
,director ,u4 ,s4 ,g4 ,s4               
--,boulder ,belts ,distinguished from   
,boulder ,trains--,their ,origin and    
,significance4 #d pp4--,bull4 ,geol4    
,soc4 ,am4 ,vol4 ,i41 #ahgi4            
--,some ,additional ,evidence ,bearing  
on the ,interval between the            
,glacial ,epochs4 #aa pp4--,bull4 ,geol4
 ,soc4 ,am41 ,vol4 ,i41 #ahij4          
--,the ,attitude of the ,eastern and    
,central ,portions of the ,united       
,states during the ,glacial ,period4 #h 
pp4--,am4 ,geol41 ,nov4 #ahia4      --,a
 ,proposed ,system of ,chronologic      
,cartography on a ,physiographic        
,basis4 #c pp4--,bull4 ,geol4 ,soc4     
,am41 ,vol4 ,,ii41 #ahia4      --7and   
,r4 ,d4 ,,salisbury47      --,on the    

,relationship of the ,pleistocene to the
 ,pre-,pleistocene     ,formation of the
 ,mississippi ,basin1 ,south of the     
,limit of     ,glaciation4 #ag pp4--,am4
 ,jour4 ,sci41 ,vol4 ,,xli41 ,may #ahia4
  ,,chaney1 ,l4 ,w4 ,,jr4               
--,cryptozon ,minnesotense in the       
,shakopee ,limestone at ,northfield1    
,minn4 #c pp4--,bull4 ,minn4 ,acad4     
,sci41 ,vol4 ,,iii41 ,no4 #b4  ,,clarke1
 ,,professor ,f4 ,w4      --,a ,number  
of ,pamphlets by ,different ,authors2 #e
 ,volumes of the     ,hayden ,survey of 
the ,territories4  ,,cooke1 ,j4 ,h4     
--,geological ,notes on ,gozo4 #f       
pp4--,geol4 ,mag41 ,aug4 #ahia4         
--,notes on ,stereodon ,melitensis1     
,owen4 #b pp4--,geol4 ,mag41 ,dec4      
#ahia4      --,on the ,occurrence of a  
,black ,limestone in the ,strata of the 
,maltese ,islands4 #c pp4--,geol4 ,mag41
 ,aug4 #ahib4      --,the ,mediterranean
 ,naturalist4 ,from ,aug4 #a1 #ahia1 to 
,sept4 #a1     #ahib1 inclusive4        
,,crosby1 ,w4 ,o4      --,notes on the  

,physical ,geography and ,geology of    
,trinidad4 #aa     pp4--,proc4 ,boston  
,soc4 ,nat4 ,hist41 ,oct4 #ahhh4        
--,on the ,joint ,structure of ,rocks4  
#e pp4      --,on a ,possible ,origin of
 ,petrosilicious ,rocks4 #i pp4--,proc4 
,boston     ,soc4 ,nat4 ,hist41 ,march  
#ahgi4      --,on the ,classification of
 the ,textures and ,structures of       
,rocks4 #i     pp4--,proc4 ,boston ,soc4
 ,nat4 ,hist41 ,nov4 #ahha4      --,on  
the ,elevated ,reefs of ,cuba4 #f       
pp4--,proc4 ,boston ,soc4 ,nat4         
,hist41 ,june #ahhc4      --,on the     
,chasm called 8,purgatory10 in ,sutton1 
,mass4 #b pp4--,proc4     ,boston ,soc4 
,nat4 ,hist41 ,oct4 #ahhc4              
--,origin of ,continents4 #aa           
pp4--,geol4 ,mag41 ,june #ahhc4         
--,on the ,relationship of the          
,conglomerate and ,slate in the ,boston 
,basin4 #bj pp4--,proc4 ,boston ,soc4   
,nat4 ,hist41 ,jan4 #ahhd4              
--,quartzites and ,siliceous            
,concretions4 #aj pp4--,technology      

,quarterly1 ,may1 #ahhh4                
--,relations of the ,pimite of the      
,boston ,basin to the ,felsite and      
,conglomerate4 #ad pp4--,technology     
,quarterly1 ,feb4 #ahhi4      --,the    
,madison ,bowlder4 #i pp41 #a           
pl4--,appalachia1 ,vol4 ,,vi1 ,no4 #a4  
--,on the ,contrast in ,color of the    
,soils of ,high and ,low ,latitudes4    
#aj pp4      --,geology of the ,outer   
,islands of ,boston ,harbor4 #h         
pp4--,proc4     ,boston ,soc4 ,nat4     
,hist41 #ahhh4      --,physical ,history
 of the ,boston ,basin4 #bb             
pp4--,lectures to     ,teachers' ,school
 of ,science1 #ahhi-ij4      --,the     
,kaolin in ,blandford1 ,mass4 #i        
pp4--,technology ,quarterly1 ,aug4      
#ahij4      --,composition of the ,till 
or ,boulder-,clay4 #be pp4--,proc4      
,boston     ,soc4 ,nat4 ,hist41 ,vol4   
,,xxv1 #ahij4      --,geology of        
,hingham1 ,mass4 #ab pp41 #c            
maps4--,proc4 ,boston ,soc4 ,nat4       
,hist41 ,vol4 ,,xxv1 ,may1 #ahib4       

--,geology of the ,black ,hills of      
,dakota4 #bi pp4--,proc4 ,boston ,soc4  
,nat4 ,hist41 ,vol4 ,,xxiii4  ,,culver1 
,g4 ,e4      --,on a ,little ,known     
,region of ,northwestern ,montana4 #ah  
pp41 #a     pl4--,wis4 ,acad4 ,sci41    
,arts and ,letters1 ,dec4 #ahia4        
,,darton1 ,n4 ,h4      --,the ,relations
 of the ,traps of the ,newark ,system in
 the ,new ,jersey     ,region4 #hb pp41 
#a map1 #d pl4--,bull4 ,u4 ,s4 ,g4 ,s4  
--,on ,fossils in the ,lafayette        
,formation in ,virginia4 #c pp4--,am4   
,geol41 ,march1 #ahib4  ,,derby1 ,o4 ,a4
      --,on ,nepheline ,rocks in        
,brazil4 #ae pp41 ,ill4--,quart4 ,jour4 
,geol4     ,soc41 #ahia4  ,,douglas1    
,,james4      --,biographical ,sketch of
 ,thomas ,sterry ,hunt4 #aa pp4--,trans4
 ,am4     ,inst4 ,min4 ,engin4          
,,eyerman1 ,,john4      --,notes on     
,geology and ,mineralogy4 #d pp4--,proc4
 ,acad4 ,nat4 ,sci41     ,phila41 #ahhi4
      --,the ,mineralogy of             
,pennsylvania1 ,part ,i4 #ed pp4        

--,bibliography of ,north ,american     
,vertebrate ,paleontology for the       
year #ahhi4 #d pp4--,am4 ,geol41 #ahij4 
--,bibliography of ,north ,american     
,vertebrate ,paleontology for the       
year #ahij4 #h pp4--,am4 ,geol41 #ahia4 
--,on the ,mineralogy of the ,french    
,creek ,mines in ,pennsylvania4 #d      
pp4--,n4 ,y4 ,acad4 ,sci41 #ahhi4       
--,a ,catalogue of the ,paleontological 
,publications of ,joseph ,leidy1        
,m4,d41 ,,ll4,d4 #aj pp4--,am4 ,geol41  
,nov4 #ahia4      --,bibliography of    
,north ,american ,vertebrate            
,paleontology for the     year #ahia4 #h
 pp4--,am4 ,geol41 ,april1 #ahib4       
,,felix1 ,,johannes4                    
--,untersuchungen ueber fossile ,hlzer4 
#ab pp41 #a pl4--,abdruck a4 d4         
,zeitschr4 ,deutschen geolog4 ,gesell41 
#ahhg4      --,beitrge zur ,kenntniss   
der ,gattung ,protosphyraena ,leidy4 #bd
 pp41     #c pl4--,aus der ,zeitschr4   
,deutschen geolog4 ,gesell41 #ahij4     
--,ueber die tektonischen               

,verhltnisseder ,republik ,mexiko4 #bj  
pp41 #b     pl4--,aus der ,zeitschr4    
,deutschen geolog4 ,gesell41 #ahib4     
,,ferrier1 ,w4 ,f4      --,rapport      
,gologique4 ,rapport des ,oprations de  
#ahff  #ahfi4 #ecj     pp41 with maps4  
--,descriptive ,sketch of the ,physical 
,geography and ,geology of the          
,dominion of ,canada1 by ,alfred ,r4 ,c4
 ,selwyn and ,g4 ,m4 ,dawson4 #ee pp4   
#ahhd4      --,list of ,publications of 
the ,geological and ,natural ,history   
,survey     of ,canada4 #cf pp4         
--,geological and ,natural ,history     
,survey and ,museum of                  
,canada4--,report of ,progress1         
#ahhb-hc-hd4 ,annual ,report for        
#ahhh-hi4  ,,fisher1 ,,rev4 ,o4         
--,the ,hypothesis of a ,liquid         
,condition of the ,earth's ,interior    
considered in ,connection with          
,professor ,darwin's ,theory of the     
,genesis of the ,moon4 #ad pp4--,proc4  
,cambridge ,phil4 ,soc41 #ahib4         
,,gilbert1 ,g4 ,k4      --,continental  

,problems4 ,annual ,address by the      
,president of the     ,geological       
,society of ,america4 #ab pp41          
,ill4--,bull4 ,geol4 ,soc4 ,am41        
#ahic4      --,the ,moon's ,face4 ,a    
,study of the ,origin of its ,features4 
#eb pp41 #a     pl4--,phil4 ,soc4       
,washington1 #ahic4  ,,degeer1 ,,baron  
,,gerard4      7,the following pamphlets
 are in the ,swedish language1 the      
titles     being translated73      --,on
 the ,occurrence of ,hydrous ,manganese 
,oxide between the ,pebbles     of the  
,osar at ,upsala4 #d pp4--,aftryck ur   
,geol4 ,freningens i     ,stockholm     
,frhandl41 #ahhb4      --,on            
,actinocamax ,quadratus4 #c pp4--,ibid4 
,bd4 ,,vii4      --,on ,kaolin and other
 ,minerals1 derived from decayed        
,archaean rocks     in the ,cretaceous  
near ,kristianstad4 #h pp4--,ibid4 ,bd4 
,,vii4      --,discussion of the        
,conglomerate at ,vestani in ,scania4 #e
 pp4--,ibid4     #ahhf4      --,on      
,folded ,veins in ,archaean ,rocks4 #e  

pp4--,ibid4 #ahhg4      --,on ,windworn 
,stones4 #bj pp4--,ibid4 #ahhg4         
--,on the ,cave of ,barnakoella1 a new  
exposure of the ,cretaceous in          
,scania 7in ,southern ,sweden74 #bb pp4 
--,on the ,earlier ,baltic ,ice-,stream 
in ,eastern ,scania4 #d pp4--,ibid4     
,bd4 ,x4      --,description of the ,map
 sections ,vidtskoefle1 ,karlshamn      
7,scanian     part71 and ,soelvsborg    
7,scanian part74 #hh pp4 #ahhi4         
--,description of the ,map section      
,baeckaskog4 #aaj pp4 #b pl41 #a map1   
#ahhi4      --,on the ,situation of the 
,ice ,shed during the two ,glaciations  
of     ,scandinavia4 #bj pp4 #ahhi4     
--,on the ,quaternary ,changes of ,level
 in ,scandinavia4 #ff pp4 #a            
map4--,ibid4 #ahhh-ij4      --,on a     
,series of ,small ,dump ,moraines near  
,stockholm1 probably     marking the    
annual recession of the ,ice ,border4 #c
 pp4--,ibid4 ,dec4     #ahhi4      --,on
 the ,relation between the ,carbonates  
of ,lime and ,magnesia in               

,limestones 7,cretaceous and ,silurian74
 #d pp4--,ibid4 #ahhi4      --,on the   
,origin of the ,lakes in ,eastern       
,scania4 #d pp4--,ibid4 ,jan4     #ahhi4
      --,on the ,latest ,investigations 
of the ,terminal ,moraines ,south of    
the ,baltic4 #d pp4--,ibid4 ,april1     
#ahhi4      --,on ,continental ,changes 
of ,level in ,scandinavia and ,north    
,america4     #d pp4--,ibid4 ,feb4      
#ahib4      --,ueber ein ,conglomerat im
 ,urgebirge bei ,vestana in ,schonen4   
#bh pp4 #a pl4 7,german ,uebersetzt von 
,felix ,wahnschaffe in                  
,berlin74--,zeitschr4 d4 ,deutschen     
geolog4 ,gesell4 #ahhf4                 
--,quaternary ,changes of ,level in     
,scandinavia 7,english74 #d pp41 #a     
map4--,bull4 ,geol4 ,soc4 ,am41 ,vol4   
#c1 #ahia4      --,on ,pleistocene      
,changes of ,level in ,eastern ,north   
,america4 #bb pp41     #a map           
7,english74--,proc4 ,bost4 ,soc4 ,nat4  
,hist41 #ahib4  ,,hall1 ,c4 ,w4         
--,the ,deep ,well at ,minneopa1        

,minnesota4 #c pp4--,bull4 ,minn4 ,acad4
     ,nat4 ,sci41 ,vol4 ,,iii41 ,no4 #b4
  ,,hallock1 ,,william4                 
--,preliminary ,report of ,observations 
at the ,deep ,well at ,wheeling1     ,w4
 ,va4 #c pp4--,proc4 ,a4 ,a4 ,a4 ,s4    
#ahia4      --7and ,f4 ,kohlrausch47    
--,ueber den ,polabstand1 den           
,inductions--und                        
,temperatur--,coefficient     eines     
,magnetes und ueber die ,bestimmung von 
,trgheitsmomenten durch                 
,bifilarsuspension4 #bj                 
pp4--,nachrichten ,koenigliche          
,gesellschaft der     ,wissenschaften1  
#ahhc4  ,,hatcher1 ,j4 ,b4      --,the  
,titanotherium ,beds4 #ah pp41          
,ill4--,am4 ,naturalist4 #ahic4         
--,the ,ceratops ,beds of ,converse     
,county1 ,wyoming4 #aj pp4--,am4 ,jour4 
,sci4 ,feb4 #ahic4  ,,hay1 ,o4 ,p41     
,,ph4,d4      --,the ,northern ,limits  
of the ,mesozoic ,rocks in ,arkansas4   
#cj     pp4--,annual ,report ,geol4     
,surv4 ,ark4 #ahhh4  ,,hobbs1 ,,wm4 ,h4 

--,secondary ,banding in ,gneiss4 #f pp4
 #a pl41 ,ill4--,bull4 ,geol4 ,soc4     
,am41 #ahia4      --,notes on a ,trip to
 the ,lipari ,islands4 #ab pp4 #a pl41  
,ill4--,wis4     ,acad4 ,sci41 #ahib4   
--,on ,intergrowths of ,hornblende with 
,augite in ,crystalline ,rocks4 #a      
p4--,science1 ,dec4 #bc1 #ahib4         
--,phases in the ,metamorphism of the   
,schists of ,southern ,berkshire4       
#ab pp4 #a pl41 ,ill4--,bull4 ,geol4    
,soc4 ,am41 ,feb4 #ahic4  ,,holmes1 ,w4 
,h4      --,geology of the ,elk         
,mountains1 ,col4 7#ahgd47              
--,geology of ,southwestern ,colorado4  
7#ahge47      --,geology of the         
,yellowstone ,park4 7#ahhj47  ,,holst1  
,n4 ,o4      --,matricit och            
,marmairolit1 tvaenne nya ,mineralier   
fran ,vermland4 #e     pp4--,aftryck ur 
,geologiska ,freningens i ,stockholm    
,frhandlingar1     #ahge4      --,om de 
glaciala rullstensasrne4 #af            
pp4--,ibid41 #ahgf4      --,klotdiorit  
fran ,slttmossa1 ,jreda socken1 ,kalmar 

ln4 #aj pp4 #a     pl4--,ibid41 ,bd4    
,,vii4      --,om ,ett ,fynd af ,uroxe i
 ,rakneby1 ,ryssby ,sockenk ,kalmar ln4 
#ba pp4     #b pl4--,ibid41 ,bd4 ,x1    
#ahhh4      --,hvem fann den norrlandska
 andesiten8 #f pp4 ,ibid4--,bd4 ,x1     
#ahhh4      --,om en ,mktig qvarsit1    
yngre n olenus-skiffer4 #c pp4--,ibid4  
,bd4     ,,xi1 #ahhi4      --,om en     
nyupptckt fauna i block af kambrisk     
sandsten1 insamlade af     dr ,n4 ,o4   
,holst af ,joh4 ,chr4 ,moberg4 #ah pp4  
#a pl4--,ibid41 ,bd4 ,,xiv1     #ahib4  
--,bidrag till ,knnedomen om            
,lagerfldjen inom den ,kambriska        
,sandstenen4 #ag pp4      --,ryoliten   
vid ,sjoen ,mien4 #eb pp4 #a pl41 ,ill4 
--,berttelse om en ar #ahhj1 i          
,geologiskt ,syfte ,foretagen ,resa     
,till     ,groenland4 #gd pp4 #a map1   
#ahhj4  ,,hovey1 ,,edmund ,,otis4       
--,observations on some of the ,trap    
,ridges of the                          
,east-,haven--,branford1 7,ct47 ,region4
 #bc pp4 #a pl4--,am4 ,jour4 ,sci41     

,nov4 #ahhi4  ,,hyatt1 ,,alpheus4       
--,remarks on the ,pinnidae4 #ab pp4    
--,jura and ,trias at ,taylorville1     
,california4 #ah pp4--,bull4 ,geol4     
,soc4 ,am41 ,vol4 ,,iii1 #ahib4         
,,iddings1 ,j4 ,p4      --,obsidian     
,cliff1 ,yellowstone ,national ,park4   
#dh pp4 #i pl41 #ahhh4     #gth ,annual 
,rept4 ,u4 ,s4 ,g4 ,s4      --,on the   
,crystallization of ,igneous ,rocks4 #ej
 pp4--,phil4 ,soc4     ,washington1     
,vol4 ,,xi1 #ahhi4      --,on a ,group  
of ,volcanic ,rocks from the ,tewan     
,mountains1 ,new     ,mexico1 and on the
 ,occurrence of ,primary ,quartz in     
certain ,basalts4     #cb pp4--,bull4   
,u4 ,s4 ,g4 ,s41 ,no4 #ff4              
--,spherulitic ,crystallization4 #ah pp4
 #b pl4--,bull4 ,phil4 ,soc4            
,washington1 ,vol4 ,,xi1 #ahia4         
--,the ,origin of ,igneous ,rocks4 #abd 
pp4 #a pl4--,bull4 ,phil4 ,soc4         
,washington1 ,vol4 ,,xii1 ,may1 #ahib4  
,,james1 ,,jos4 ,f4      --,manual of   
the ,paleontology of the ,cincinnati    

,group4 #af pp41     ,ill4--,cincinnati 
,soc4 ,nat4 ,hist41 ,oct4 #ahib1 ,jan4  
#ahic4  ,,jimbo1 ,k4      --,general    
,geological ,sketch of ,hokkaido1 with  
special reference to     the            
,petrography4  ,,judd1 ,,prof4 ,j4 ,w4  
--,a ,problem for ,cheshire ,geologists4
 #e pp4--,proc4 ,chester ,soc4 ,nat4    
,sci41 #ahhd4      --,on ,krakatoa4 #d  
pp4 #ahhd4      --,address to the       
,geological ,section of the ,british    
,association4     #ahhe4 #bj pp4        
--,on ,marekanite and its ,allies4 #h   
pp4--,geol4 ,mag41 ,june1 #ahhf4        
--,address delivered at the ,anniversary
 ,meeting of the ,geological            
,society of ,london4 ,feb4 #ah1 #ahhg1  
#eg pp4 ,feb4 #ag1 #ahhh1 #ef pp4       
--,on a ,cetacean from the ,lower       
,oligocene of ,hampshire4 #f pp41       
,ill4--,quart4 ,jour4 ,geol4 ,soc41     
,nov41 #ahha4      --,on the ,gabbros1  
,dolerites1 and ,basalts of ,tertiary   
,age1 in     ,scotland and ,ireland4 #di
 pp41 #d pl4--,ibid41 ,feb41 #ahhf4     

--,the ,tertiary ,volcanoes of the      
,western ,isles of ,scotland4 #cb       
pp4--,ibid41 ,may1 #ahhi4      --,on the
 ,growth of ,crystals in ,igneous ,rocks
 after their     ,consolidation4 #aj    
pp41 #a pl4--,ibid41 ,may1 #ahhi4       
--,the ,propylites of the ,western      
,isles of ,scotland and their           
,relation to the ,andesites and         
,diorites of the ,district4 #dd pp41 #b 
pl4--,quart4 ,jour4 ,geolog4 ,soc41     
,aug41 #ahij4      --,on the ,relation  
of the ,reptiliferous ,sandstone of     
,elgin to the     ,upper ,old ,red      
,sandstone4 #aj pp4--,proc4 ,royal      
,soc41 ,no4 #bda1 #ahhe4      --,on the 
,relations between the ,solution-,planes
 of ,crystals and     those of          
,secondary ,twinning1 and on the ,mode  
of ,development of     ,negative        
,crystals along the ,former4 #ab pp41 #a
 pl4--,mineralogical     ,magazine4     
--,on the ,development of a ,lamellar   
,structure in ,quartz-,crystals by      
,mechanical means4 #i pp41 #a           

pl4--,ibid4      --,on the ,relations   
between the ,gliding ,planes and the    
,solution     ,planes of ,augite4 #e pp4
 #ahij4      --,chemical ,changes in    
,rocks under ,mechanical ,stresses4 #bb 
pp4--,journal of the ,chemical ,society1
 ,may1 #ahij4      --,the               
,rejuvenescence of ,crystals4 #h        
pp4--,royal ,institute1 #ahia4  ,,keith1
 ,,arthur4      --,geology of ,chilhowee
 ,mountain in ,tennessee4 #ah pp41 #a   
pl4--,bull4     ,phil4 ,soc41           
,washington1 ,vol4 ,,xii41 pp4 #ga-hh4  
#ahib4      --,the ,structure of the    
,blue ,ridge1 near ,harper's ,ferry4 #aj
 pp41 #b     pl4  ,,knowlton1 ,f4 ,h4   
--,bread-,fruit ,trees in ,north        
,america4--,science1 ,jan4 #ac1 #ahic4  
,,lawson1 ,a4 ,c4      --,geology of the
 ,rainy ,lake ,region1 with ,remarks on 
the     ,classification of the          
,crystalline ,rocks west of ,lake       
,superior4 #h     pp4--,am4 ,jour4      
,sci41 ,june1 #ahhg4      --,notes on   
,some ,diabase ,dykes of the ,rainy     

,lake ,region4 #ad pp41 ,ill4           
--,notes on the ,occurrence of ,native  
,copper in the ,animikie ,rocks of      
,thunder ,bay4 #e pp4--,am4 ,geol41     
,march1 #ahij4      --,notes on the     
,pre-,paleozoic ,surface of the ,archean
 ,terranes of     ,canada4 ,the         
,internal ,relations and ,taxonomy of   
the ,archean of     ,central ,canada4   
#cb pp4--,bull4 ,geol4 ,soc4 ,am41      
#ahij4      --,petrographical           
,differentiation of ,certain ,dykes of  
the ,rainy ,lake     ,region4           
,,lindgren1 ,,waldemar4                 
--,petrographical ,notes from ,baja1    
,california1 ,mexico4 #ag pp4--,proc4   
,cal4 ,acad4 ,sci41 #b;d ,ser4 ,,ii4    
7#ahhi71 #i pp4 ,vol4 ,,iii4 7#ahij74   
--,eruptive ,rocks from ,montana4 #ah   
pp4--,ibid41 ,vol4 ,,iii4      --,the   
,silver ,mines of ,calico1 ,california4 
#ah pp41 #a pl4--,trans4 ,am4     ,inst4
 ,min4 ,engin4      --,the ,gold        
,deposit at ,pine ,hill1 ,california4 #f
 pp4--,am4 ,jour4 ,sci41     ,aug41     

#ahib4      --,a ,sodalite-,syenite and 
other ,rocks from ,montana2 with        
,analysis1     by ,w4 ,h4 ,melville4 #ab
 pp4--,ibid41 ,april1 #ahic4            
--,contributions to the ,mineralogy of  
the ,pacific ,coast1 by ,w4 ,h4         
,melville and ,w4 ,lindgren4 #cb pp41 #c
 pl4--,bull4 ,u4 ,s4 ,g4 ,s41 #ahij1    
,no4 #fa4  ,,lyman1 ,,benjamin ,,smith4 
--,shippen and ,wetherill ,tract4 #cf   
pp41 with map4  ,,martin1 ,f4 ,w4       
--,the ,boulders of the ,midland        
,district4 #bb pp41 with map4--,proc4   
,birmingham ,phil4 ,soc41 ,vol4 ,,vii41 
,part ,i4      --,first ,report upon the
 ,distribution of ,boulders in ,south   
,shropshire and ,south ,staffordshire4  
#be pp4--,ibid41 ,vol4 ,,vi41 ,pt4 ,i4  
,,marsh1 ,o4 ,c4      --,restoration of 
,claosaurus and ,ceratosaurus4          
,restoration of     ,mastodon           
,americanus4 #h pp41 #c pl4--,am4 ,jour4
 ,sci41 ,oct41 #ahib4                   
--,restoration of ,anchisaurus4 #b pp41 
#a pl4--,ibid41 ,feb41 #ahic4           

,,merriman1 ,,mansfield4      --,the    
,strength and ,weathering ,qualities of 
,roofing ,slates4 #ai pp41     #c       
pl4--,am4 ,soc4 ,civil ,engin41 ,sept41 
#ahib4  ,,mill1 ,,hugh ,,robert4        
--,on the ,physical ,conditions of the  
,water in the ,clyde ,sea-,area4 #be    
pp41 #a pl4--,phil4 ,soc4 ,glasgow1     
#ahhg4      --,configuration of the     
,clyde ,sea-,area4 #g pp4 #a            
pl4--,scott4 ,geog4     ,mag41 ,jan41   
#ahhg4      --,recent ,physical         
,research in the ,north ,sea4 #ad pp4   
with     map4--,ibid41 ,aug41 #ahhg4    
--,the ,relations between ,commerce and 
,geography4 #ac pp4--,ibid41     ,dec41 
#ahhg4      --,sea ,temperatures on the 
,continental ,shelf4 #f pp4--,ibid41    
,oct41     #ahhh4      --,scientific    
,earth-,knowledge as an ,aid to         
,commerce4 #ah pp4--,ibid41     ,june1  
#ahhi4      --,statical ,oceanography--a
 ,review4 #g pp4--,ibid41 ,may1 #ahia4  
--,the ,principles of ,geography4 #g    
pp4--,ibid41 ,feb41 #ahib4      --,on   

the ,physical ,conditions of the ,water 
in the ,firth of ,forth4 #f     pp41 #d 
pl4--,appendix to #eth ,annual ,report  
of the ,fishery ,board for              
,scotland4      --,report of ,physical  
,observations on the ,sea to the ,west  
of ,lewes1     during ,july and ,august1
 #ahhg4 #bf pp41 #a pl4--,ibid41 #fth   
,annual4      --,report on a ,physical  
and ,chemical ,examination of the ,water
 in the     ,moray ,firth and the       
,firths of ,inverness1 ,cromarty1 and   
,dornoch4 #cf     pp41 #d pl4--,ibid4   
--,report on the ,apparatus required for
 carrying on ,physical     ,observations
 in connection with the ,fisheries4 #d  
pp41 #b pl4--,ibid4      --,report on   
the ,physical ,observations carried on  
by the ,fishery     ,board for ,scotland
 in the ,firths of ,forth and ,tay and  
in the ,clyde     ,sea-,area4 #ce pp41  
#b pl4--,ibid41 ,ninth ,annual1 ,part   
,,iii4      --,river ,entrances4 #ab    
pp4--,supplem4 ,paper1 ,roy4 ,geog4     
,soc41 ,vol4     ,,ii41 ,part ,,iii4    

--,marine ,temperature ,observations4 #i
 pp4--,quart4 ,jour4 ,royal ,met4       
,soc4      --,on the ,tidal ,variation  
of ,salinity and ,temperature in the    
,estuary     of the ,forth4 #aj pp4 #a  
pl4--,proc4 ,royal ,soc4 ,edin41        
#ahhe-f4      --,the ,salinity and      
,temperature of the ,moray ,firth1 and  
the ,firths     of ,inverness1          
,cromarty1 and ,dornoch4 #ab pp41 #a    
pl4--,ibid41 #ahhg4      --,on the ,mean
 ,level of the ,surface of the ,solid   
,earth4 #d     pp4--,ibid41 #ahhi-ij4   
--,the ,clyde ,sea-,area4 #hh pp41 #ab  
plates and maps4      --,contributions  
to ,marine ,meteorology ,resulting from 
the ,three     ,years' ,work of the     
,scottish ,marine ,station4 #h pp4      
--,observations of ,sea ,temperature1   
made by ,staff of the ,scottish         
,marine ,station between #ahhd and      
#ahhg4 #fd pp4      --,fourth and ,final
 ,report of the ,committee appointed to 
arrange an     ,investigation of the    
,seasonal ,variations of ,temperature in

 ,lakes1     ,rivers1 and ,estuaries4   
#eb pp41 #a pl4--,british ,a4 ,a4 ,s41  
#ahia4  ,,osborn1 ,,henry ,f41 ,,sc4,d4 
--,a ,memoir upon ,loxolophodon and     
,uintatherium1 ,accompanied by a        
,stratigraphical ,report of the ,bridger
 ,beds in the ,washakie ,basin1     by  
,john ,bach ,mc,master1 ,c4 ,e4 #ed pp41
 #f pl4--,contributions from     the ,e4
 ,m4 ,museum of ,geology and ,archology 
of the ,college of ,new     ,jersey1    
,july1 #ahha4  ,,penck1 ,,albrecht      
--,ueber ,palagonit und ,basaltuffe4 #gd
 pp4--,ibid41 #ahgi4      --,ueber      
einige ,kontaktgesteine les             
,kristiania-,silurbeckens4 #bj          
pp4--,magazin for ,naturvidenskaferne1  
#ahgi4      --,studien ber lockere      
vulkanische ,answrflinge4 #cc pp41 #a   
pl4--a4     d4 ,zeitschr4 d4 ,deutsch4  
,geolog4 ,gesellschaft1 #ahgh4          
--,bericht ber eine gemeinsame          
,excursion in den ,bhmerwald4 #aj       
pp4--,ibid41 #ahhg4      --,erluterungen
 zur geologischen ,specialkarte des     

,knigreichs     ,sachsen4 ,section      
,colditz4 #ei pp41 #ahgi4               
--,glaciers of the ,isar and the ,linth4
 #h pp4 ,geol4 ,mag41 ,june1 #ahhf4     
--,die ,deutschen ,ksten4 #i pp4        
--,ziele der ,erdkunde im ,oesterreich4 
#af pp4      --,theorien ber das        
,gleichgewicht der ,erdkruste4 #bf pp41 
#ahhi4      --,das ,endziel der ,erosion
 und ,denudation4 #ab pp4--a4 d4        
,verhandlungen des ,,viii ,deutschen    
,geographentages zu ,berlin4 #ahhi4     
--,der ,flcheninhalt der                
sterreichisch-ungarischen ,monarchie4 #f
     pp4--a4 d4 ,sitzungsberichten der  
,kais4 ,akademie d4 ,wissenschaften     
in ,wien4 #ahhi4      --,die            
,glacialschotter in den ,ostalpen4 #ba  
pp4--,verlag des d4 u4 ,oe4             
,alpenvereins4      --,die ,geographie  
an der ,wiener ,universitt4 #af pp4--a4 
d4 ,geog4     ,abhandlungen4      --,die
 ,donau4 #aja pp41 #b pl4--,vortrge des 
,vereines zur ,verbreitung              
naturwissenschaftlicher ,kenntnisse in  

,wien4 #ahia4      --,ueber die         
,herstellung einer ,erdkarte im         
,mass-stabe von #a3ajjjjjj4     #cj     
pp4--,deutsche ,geog4 ,bltter ,bd4 ,,xv1
 h4 #c u4 #d4      --,bericht ber die   
,ausstellung des ,,ix ,deutschen        
,geographentages zu     ,wein4 #ahia4   
#add pp4      --,der neunte deutsche    
,geographentag in ,wien4 #bd pp4--aus   
,oesterr-,ungar4 ,revue1 #ahia4         
--,die ,formen der ,landoberflche4 #aj  
pp4--a4 d4 ,verhandlungen des ,,ix      
d4 ,geographentages in ,wien4 #ahia4    
--,das ,studium der ,geographie4 #ae    
pp4--a4 d4 ,,xvii ,jahresberichte des   
,vereines der ,geographen an der        
,universitt ,wien4  ,,prosser1 ,,charles
 ,s4      --,notes on the ,geology of   
,skunnemunk ,mountain1 ,orange ,county1 
,n4 ,y4     #ah pp4--,trans4 ,n4 ,y4    
,acad4 ,sci41 ,june1 #ahib4  ,,russell1 
,i4 ,c4      --,on the ,former ,extent  
of the ,triassic ,formation of the      
,atlantic     ,states4 #aj pp4--,am4    
,naturalist1 ,oct41 #ahhj4      --,the  

,physical ,history of the ,triassic     
,formation of ,new ,jersey and     the  
,connecticut ,valley4 #ce pp4--,n4 ,y4  
,acad4 ,sci41 #ahgh1 pp4 #bbj-bed4      
,,sieger1 ,,dr4 ,,robert4      --,die   
,schwankungen der ,hocharmenischen ,seen
 seit #ahjj in     vergleichung mit     
einigen verwandten ,erscheinungen4 #hj  
pp41 #a pl4  ,,sollas1 ,w4 ,j4 ,b4 ,a41 
,f4 ,g4 ,s4      --,on the ,perforate   
,character of the ,genus ,webbina1 #d   
pp41 #a pl4      --,on the ,silurian    
,district of ,rhymney and ,pen-y-lan1   
,cardiff1 #cb     pp41 #a pl4--,quart4  
,jour4 ,geol4 ,soc4 #ahgi4      --,on   
,astroconia ,granti1 from the ,silurian 
,formation of ,canada1 #f     pp4       
,ill4--,ibid4 ,may #ahha4      --,on a  
,new ,species of ,plesiosaurus from the 
,lower ,lias of     ,charmouth1 #dd pp41
 #b pl4      --,on the ,origin of       
,freshwater ,faunas3 ,a ,study in       
,evolution1 #c     pp4--,sci4 ,proc41   
,royal ,dublin ,soc4 #ahhd4      --,the 
8,coecal ,processes0 of the ,shells of  

,brachiopods interpreted     as ,sense  
,organs1 #c pp4--,ibid41 ,nov4 #ah1     
#ahhe4      --,a ,contribution to the   
,history of ,flints1 #e pp4--,ibid41    
,dec4 #ad1     #ahhg4      --,on        
,homotoechus 7,archocidaris ,harteana1  
,baily7 ,a new ,genus of     ,palaeozoic
 ,echinoids1 #c pp4--,ibid41 ,june #ag1 
#ahia4      --,on the ,structure and    
,origin of the ,quartzite ,rocks in the 
,neighborhood of ,dublin1 #bj pp41 #a   
pl41 ,ill4--,ibid41 ,feb4 #ag1 #ahib4   
--,on the ,variolite and ,associated    
,igneous ,rocks of ,round ,wood ,co4    
,wicklow1 #bb pp4 ,ill4--,ibid41 ,march 
#be1 #ahic4      --,on ,pitchstone and  
,andesite from ,tertiary ,dykes in      
,donegal4 #g pp4     ,ill4--,ibid41     
,march #be1 #ahic4      --,on the       
,occurrence of ,zinnwaldite in the      
,granite of the ,mourne     ,mountains1 
#b pp4--,proc4 ,royal ,irish ,acad4     
#ahij4 #c;d ,ser4 ,vol4 #a2 ,no4     #c4
  ,,steenstrup1 ,j4 ,,japetus ,s4 ,m4   
--,sur les ,kjokkenmoddings de l',age de

 la ,pierre et sur la ,faune     et la  
,flore ,prhistoriques de ,danmark4 #dj  
pp41 #b pl4 ,ill4--,bull4     ,congrs   
,international d',archologie            
,prhistorique  ,copenhague1     #ahfi4  
--,torvemosernes ,bidrag til ,kundskab  
om ,danmark's forhistorische     ,natur 
og ,kultur1 #db pp4      --,die         
,mammuthjger-,station bei ,predmost im  
oesterreichischen     ,kronlande ,mhren4
 #ca pp4--,mittheil4 der                
,anthropologischen ,gesell41     in     
,wien1 #ahij4      --,hvorledes dannes  
de store ,isfjaelde8 #g pp4--,saertryk  
af     8,geografisk ,tidskrift40        
,,steinmann1 ,g4      --,die ,mornen am 
,ausgange des ,wehrathals1 #f pp4       
,ill4--a4 d4 ,bericht     ber die ,,xxv4
 ,versammlung des ,oberrheinischen      
geolog4 ,vereins ,zu     ,basel4        
--,die ,mornen am ,ausgange des         
,wehrathals1 #e pp4--,ibid4             
--,bemerkungen ber die tektonischen     
,beziehungen der oberrheinischen        
,tiefebene zu dem nordschweizerischen   

,kettenjura1 #aj pp4 ,ill4--a4 d4       
,berichte der ,naturforschenden ,gesell4
 zu ,freiberg4      --,ueber die        
,ergebnisse der neueren ,forschungen im 
,pleistocn des     ,rheinthals1 #d      
pp4--a4 d4 ,zeitschs4 d4 ,deutschen     
geolog4 ,gesell4     #ahib4  ,,taylor1  
,w4 ,,edgar4      --,the ,ophidia of    
,nebraska1 #dh pp4  ,,thomassen1 ,t4    
,,ch4      --,jordskjaelv i ,norge      
#ahhh-ahij4 ,anhang3 ,deutsches ,resum  
und     tabellarische ,zusammenstellung 
der in #ahhj-ahij eingetroffenen        
,erdbeben1 #ef pp41 #b pl4              
--,berichte ber die1 wesentlich seit    
#ahcd1 in ,norwegen     eingetroffenen  
,erdbeben1 #eb pp4--a4 ,bergens ,museums
 ,aarsberetning     #ahhh4  ,u4 ,s4     
,,geological ,,survey4      --,annual   
,reports of the ,director1 #dth to      
#aath4      --,monographes1 ,,xvii1     
,,xviii1 ,,xx4      --,mineral          
,resources of the ,united ,states1 #f   
vols4 #ahhc to #ahij4      --,bulletins 
#cj1 #ef1 #fe1 #ff1 #fi1 #gj to #hd     

incl4  ,u4 ,s4 ,,coast ,,and ,,geodetic 
,,survey4      --,report ,u4 ,s4 ,coast 
,survey1 #cd ,volumes1 ,charts4  ,,van  
,,hise1 ,c4 ,h4      --,bulletin #hf ,u4
 ,s4 ,g4 ,s4 ,correlation               
,papers--,archan and     ,algonkian4    
#edi pp41 #ab pl4  ,,walcott1 ,c4 ,d4   
--,notes on the ,cambrian ,rocks of     
,pennsylvania and ,maryland1 from       
the ,susquehanna to the ,potomac4 #ad   
pp4--,am4 ,jour4 ,sci4 ,dec4 #ahib4     
,,wahnschaffe1 ,,felix4      --,bericht 
ueber den von der geologischen          
,gesellschaft in ,lille                 
veranstalteten ,ausflug in das          
,quartrgebiet des nordlichen            
,frankreich und des ,sdlichen ,belgien1 
#ab pp4--,jahrbuch der ,knigl4          
preuss4 geolog4 ,landesanstalt fr #ahia4
  ,,warring1 ,c4 ,b41 ,,ph4 ,d4         
--,geological ,climate in ,high         
,latitudes1 #af pp4--,popular ,sci4     
,monthly1 ,july1 #ahhf4  ,,westgate1    
,,lewis ,g4      --,the ,geographic     
,development of the ,eastern ,part of   

the ,mississippi     ,drainage ,system1 
#af pp4 ,am4 ,geol4 ,april #ahic4       
,,winchell1 ,h4 ,v4      --,the ,mesabi 
,iron ,range in ,minnesota1 #gb pp41 #e 
pl4--#bjth annual     ,report4 ,minn4   
,geol4 ,survey1 #ahia4  ,,winchell1 ,n4 
,h4      --,the ,crystalline ,rocks1    
,some ,preliminary ,considerations as to
     their ,structures and ,origin1 #bh 
pp4--#bjth ,annual ,report1 ,minn4      
,geol4 ,survey1 #ahia4  ,,woodworth1 ,j4
 ,b4      --,the ,ice ,wall on the      
,beach at ,hull1 ,mass41 ,january1      
#ahic4--,science4 ,feb4 #aj1 #ahic4     
7,further acknowledgments of pamphlets  
already received will be made in the    
next number47     ,transcriber's ,notes 
,punctuation1 hyphenation1 and spelling 
were made consistent when a predominant 
preference was found in the original    
book2 otherwise they were not changed4  
,simple 7and frequent7 typographical    
errors were corrected2 unbalanced       
quotation marks were remedied when the  
change was obvious1 and otherwise left  

unbalanced4  ,footnotes have been       
sequentially renumbered to make them    
unique1 and then moved to the ends of   
the articles to which they belong4      
,illustrations and references to them   
have been sequentially renumbered4      
,pages #cdd1 #cde3 ,text shown as a1 b1 
and c was printed in a ,blackletter     
font4  ,footnote #cj1 originally on page
 #cfh3 ,the page range was printed as   
shown 7with dashed placeholders72 the   
missing numbers may be #cfi and #cgj4   
,footnote #df1 originally on page #chb3 
,the citation for 8,proc4 ,bos4 ,soc4   
,nat4 ,hist40 had no further details4   
,page #daa3 ,text uses both             
8,schiefergesteinen0 and                
8,schiefergestenien04  ,footnote #fj1   
originally ,footnote #g on page #daa1   
omitted the page number reference4