,illustration3 ,no4 #a4 ,,this ,,map ,,shows ,,the ,,spread ,,of ,,glaciers ,,and ,,icebergs1 ,,and ,,the ,,extension ,,of ,,southern ,,lands ,,during ,,ice ,,age ,,and ,,also ,,the ,,direction ,,of ,,winds ,,and ,,ocean ,,currents4 ,illustration3 ,no4 #b4 ,,this ,,map ,,shows ,,the ,,spread ,,of ,,glaciers ,,and ,,icebergs ,,and ,,the ,,direction ,,of ,,winds ,,and ,,currents ,,at ,,this ,,date4 ,,the ,,coming ,,ice ,,age4 ,,by ,c4 ,a4 ,m4 ,,taber4 ,,boston3 ,,geo4 ,h4 ,,ellis1 #ada ,,franklin ,,street4 #ahif4 ,,copyright1 #ahif4 ,,by ,c4 ,a4 ,m4 ,,taber4 ,,geo4 ,h4 ,,ellis1 ,,printer1 #ada ,,franklin ,,street1 ,,boston4 ,,preface4 ,the explanations given in the following pages1 in which ,i have sought to show the manner in which an ice age is being brought about1 is an extension of a treatise on 8,the ,cause of ,warm and ,frigid ,periods10 which ,i published in a small edition in #ahid4 ,and1 from the small number of copies circulated1 only a few came to the hands of persons particularly interested in such matter4 ,yet there were instances of its having proved of special interest to persons celebrated for their geological attainments1 and also to instructors in physical geography4 ,besides1 it received considerate notice in some of the leading reviews4 ,being thus somewhat encouraged1 and thinking that the subject was too important to be neglected1 ,i have given it further study during the last year1 and meanwhile have obtained additional information from recent discoveries which has served to corroborate my views4 ,hence ,i have been able to be more explicit in my explanations in the present volume than in my earlier writings4 ,still1 while acting as a pioneer in the matter1 it will be seen that ,i have only attempted to expose the main outlines1 as my age and failing health will not permit me to enter into the voluminous details necessary for a full explanation4 ,in order to show why my attention has been turned to the great climatic changes which have taken place during past ages1 and now threaten the future1 ,i will repeat the introduction of my earlier publication1 wherein ,i wrote that 8the reason why ,i have undertaken to explain the causes which have brought about the warm and cold epochs is because of my being unable to harmonize the several theories that have been published with the general mode of action which nature pursues to-day4 ,having in the early part of my life been employed for a score of years in the whaling service1 during which time my sea voyages were passed in cruising over the ,north and ,south ,atlantic1 and over the ,indian ,ocean1 from latitudes north of the equator to the southern shores of ,kerguelen ,land1 and along the seas of ,southern ,australia1 ,i also1 in my searching1 cruised over the ,pacific ,ocean from the icy seas south of ,cape ,horn to the northern latitudes of ,alaska1 and1 from ,new ,zealand in the ,western ,pacific to the numerous islands in the tropical zone4 ,and it may be said that among the chief things to be learned on such voyages was the direction of the prevailing winds and surface currents of the sea4 ,thus the impressions then received were in mind when1 in after years1 ,i had my attention drawn to the several theories advanced for explaining the causes which produced the warm and frigid epochs4 ,but1 so far as my marine experience goes1 such theories have not harmonized with nature's mode of operating at this age of the world4 ,therefore1 ,i have conceived views which1 to my mind1 are more agreeable to the simple operations of nature of which ,i have long been witness4 ,consequently1 ,i have written several short essays on climatic changes since #ahhj1 and also letters relating to the same subject1 which have been published in ,science and ,scientific ,american4 ,but the space allowed for the introduction of such matter was necessarily too limited for so wide an explanation as the subject required4 ,the views then advanced ,i have again repeated1 with the addition of several facts pertaining to physical geography1 which1 so far as ,i know1 have never before been published40 ,,wakefield1 ,,mass41 ,u4,s4,a4 ,june1 #ahif4 ,,contents4 ,,chapter ,i4 ,,page ,,cause ,,of ,,cold ,,and ,,mild ,,periods1 #i-cf ,traces of ancient glaciers in temperate zones1 #i2 prevailing winds the main cause of the circulation of the ocean waters between the tropical and temperate zones1 #aj2 general direction of prevailing winds1 and how1 in connection with continents1 they circulate the surface waters of the sea1 #aa2 high and low sea-levels2 separation of antarctic lands from ,south ,america1 #ab2 ,captain ,larsen's discoveries in antarctic regions1 #ac2 how low lands south of ,cape ,horn were submerged1 #ac2 how the winds move more surface water southward than northward1 #ad2 ,dr4 ,croll's views on winds and ocean currents1 #af2 under-currents of the ocean1 and how caused1 #af2 ,gulf ,stream currents1 #ag2 antarctic under-currents1 #ah2 why the winds were able to force more of the ocean waters southward than northward at the close of the ,tertiary age1 #ai2 ,mr4 ,alfred ,r4 ,wallace's views on ,tertiary seas1 #bj2 how the ,cape ,horn channel affects the ocean currents1 #ba2 cause of the increase of cold in southern latitudes1 #bb2 how the ,cape ,horn channel is closed during ice age1 and its effect on ocean currents and temperature of southern latitudes1 #bd2 the melting of glaciers from southern lands1 #bg2 a salt sea requisite for circulation during ice age1 #bh2 direction of surface currents in southern seas1 #bi2 ,humboldt current1 #cj2 ,agulhas current1 #cb2 temperature of arctic ice1 #cd2 movement of southern icebergs1 #ce2 glaciers south of ,cape ,horn1 #cf4 ,,chapter ,,ii4 ,,how ,,ice ,,periods ,,in ,,the ,,northern ,,hemisphere ,,are ,,brought ,,about1 #cg-ed ,northern seas during ,tertiary age1 #cg2 ,gulf ,stream during ,tertiary times1 #ch2 the origin of a cold period in the northern hemisphere1 #ch2 remarks on ,gulf ,stream and arctic currents1 #ci2 circulation of arctic waters1 #dj2 arctic channels during ice age1 #da2 how the weight of glaciers in the northern hemisphere attracts the waters of the southern seas during ice age1 #db2 ,professor ,prestwich on the submergence of ,european lands1 #dc2 the great ,atlantic tide rips the head-waters of the ,gulf ,stream1 #dd2 high sea-level of ,atlantic calm region1 #de2 tropical ,atlantic currents1 #df2 ,sargasso ,sea1 #dh2 arctic and ,gulf ,stream currents1 #di2 ,pacific ,ocean currents1 #ej2 slow growth of an ice period1 #eb2 reduction of ,cape ,horn channel1 #ec2 permanence of antarctic glaciers elevated above the snow-line during mild periods1 #ed4 ,,chapter ,,iii4 ,,spread ,,of ,,glaciers ,,during ,,cold ,,epochs1 #ed-fa ,spread of glaciers in tropical zone1 #ed2 ,professor ,agassiz on the origin of ,galapagos ,islands1 #ee2 the bowlders of ,hood's ,island and rookery of ,albatross1 #ef2 alpine flora of ,galapagos and tropical ,america1 #eg2 ,mr4 ,j4 ,crawford on ancient glaciers in ,nicaragua1 #eh2 ,cuba and ,republic of ,colombia during ice age1 #eh2 destruction of animal life during glacial age1 #ei2 temperature of ,north ,atlantic and ,mediterranean ,sea during ice age1 #fj2 temperature of ocean during warm epochs1 #fa2 generative age ascribed to warm eras2 ,professor ,wright on pre-glacial man1 #fa4 ,,chapter ,,iv4 ,,the ,,glaciers ,,of ,,the ,,temperate ,,zone1 #fb-ge ,professor ,hitchcock on the early history of ,north ,america1 #fb2 glacial deposits of ,nantucket and ,martha's ,vineyard1 #fc2 ,professor ,james ,geikie on the glacial deposits of ,northern ,italy1 #fd2 ,california coast ranges the work of ,sierra glaciers1 #fe2 ancient glaciers on the ,pacific slope north of ,california1 #fg2 ,professor ,geikie's views on the ancient glaciers in the ,salt ,lake region1 #fh2 ,colorado ,caon1 #fi2 the conglomerate deposits in the ,appalachian district1 #fi2 remarks on the glacial boundaries in ,united ,states during ice age1 #gj2 sands of ,florida1 #ga2 ancient ice-sheets of the plains west of the ,mississippi ,river1 #gc2 the driftless region of ,wisconsin1 #gd2 tropical waters of ,north ,atlantic chilled during ice age1 #ge2 the drifted snow of ,british ,america and ,siberia during ice age1 #ge4 ,,chapter ,v4 ,,remarks ,,on ,,theories ,,advanced ,,for ,,explaining ,,ice ,,periods1 #gf-ic ,professor ,geikie on supposed causes of the glacial period1 #gf2 change in the relative level of the land and sea during glacial and post-glacial times1 #gg2 submergence of northern lands at close of ice age1 #gh2 the main cause of the movement of water from the northern seas at the close of glacial age1 #gi2 why the earth-movement hypothesis should be rejected1 #gi2 glaciers of ,europe and ,alaska1 #hj2 ,north ,pacific currents1 #ha2 why the ,pacific waters are growing cool1 #hb2 the lowering temperature of the northern seas1 #hc2 the increase of cold in ,europe and ,asia1 #hd2 falling temperature of the ,andean region1 #he2 ,general ,drayson's astronomical discoveries for explaining the cause of ice periods1 #hg2 why the ,gulf ,stream was always confined to the ,north ,atlantic1 #hi2 the improbability of the ,indian ,ocean currents entering the arctic seas1 #ij2 why the increase of glaciers must continue while the ,cape ,horn channel maintains its present capacity1 #ia2 comments on the coming ice age1 #ib2 tropical zone the abode of man during ice age1 #ic2 preservation of the tropical ocean fauna through the glacial period1 #ic4 ,,chapter ,i4 ,,cause ,,of ,,cold ,,and ,,mild ,,periods4 ,it is now generally conceded by those who have given the subject much attention that the greater portion of ,north ,america above the latitude of #ci north to the shores of the ,arctic ,ocean has been furrowed and scoured by the action of ice4 ,vast traces of ancient glaciers are also found in ,europe2 for it is reported that ice-sheets have left unmistakable marks of having overrun the greater part of the lands lying between the arctic seas and the latitude of the ,pyrenees4 ,in ,asia evidences of glacial action have been noticed from ,northern ,siberia to the mountains of ,syria4 ,the great glaciers of ,himalaya have in times past attained gigantic proportions4 ,in ,northern ,china huge bowlders are found scattered over the valleys1 and a long distance from the mountains4 ,the southern hemisphere1 in proportion to the extent of its land surface1 shows ample traces of former ice action4 ,from the latitude of #ch south to the southern extremity of the western continent there is said to be the clearest evidence of former glacial action in numerous bowlders scattered over the land4 ,on the shores of the ,south ,pacific1 from the ,island of ,chiloe to ,cape ,horn1 the coast is fringed with deep fiords1 which appear to be channelled out by ice1 like the fiords of ,norway and ,greenland4 ,and at this date the mountains of that southern region are covered with snow1 and the glaciers which flow down the valleys are said to reach the tide-water as far north as the latitude of #dg south4 ,the glaciers of ,new ,zealand1 now of ,alpine proportions1 during the ice age descended to the sea1 and channelled the deep fiords on its south-western coast2 and certain traces of glacial action have been observed in ,southern ,australia1 and also in the province of ,natal1 ,south ,africa4 ,kerguelen ,land is pierced with deep1 narrow fiords1 which have the appearance of having been the work of ancient glaciers4 ,the lands south of the antarctic circle are to-day supposed to be covered by an ice-sheet1 of which the great ice barrier surrounding that region furnishes ample proof4 ,while impressed with the above reports of the work of ancient glaciers1 in connection with my own observations along the shores of the several oceans1 ,i have been led to seek for the physical causes which brought about the great climatic changes of past geological ages4 ,and1 while having the subject under consideration1 ,i have had my attention directed to the manner in which the great prevailing winds in connection with continental lands are able to move the heated surface waters of the tropical oceans into the colder zones1 and also transfer the cold waters of the higher latitudes into the tropical zones4 ,and it is through this grand movement of the ocean waters that we are enabled to account for the difference in the temperature of places now lying in the same parallels of latitude4 ,the natural methods for conveying tropical heat into the higher latitudes1 and also for excluding it therefrom1 are so simple and efficient that on due consideration we are able to conceive how epochs possessing mild climates have been succeeded by periods of frigidity4 ,it has been admitted by several writers on climatic changes that1 should the tropical surface waters of the ocean be moved into the high latitudes in large volume1 thus adding their warmth to the heat imparted by the sun1 such combined heat would cause a mild climate4 ,and it has been estimated that the amount of equatorial heat moved into the temperate and polar regions of the northern hemisphere by the ,gulf ,stream alone is equal to one-fourth of all the heat received from the sun by the ,north ,atlantic from the tropic of ,cancer to the arctic circle4 ,still1 it appears to me1 while viewing the subject from a marine standpoint1 that the explainers of climatic changes have never fully comprehended the manner in which the surface waters of the ocean are moved from the tropics into the high latitudes1 and returned from the high latitudes to the tropics4 ,consequently1 they have neglected necessary and efficient natural agents in their explanatory theories1 and with much learning and ingenuity have laboriously sought to show how great changes of climate could be brought about through other causes4 ,but when we notice the simple methods employed by nature to-day for transferring the heat of the tropics into the higher latitudes1 and also the manner of excluding such heat therefrom1 they appear to afford an explanation for the great changes of climate which have taken place during past ages2 for it appears that the natural manner of proceeding by which heat is moved from the torrid zone into the high latitudes sufficient to cause a mild climate is through the ocean currents which are constantly set in motion by the great prevailing winds of the globe4 ,these winds1 as is well known1 blow mostly from the east toward the west in the tropics1 and from the west toward the east in the high latitudes4 ,this counter-movement of the winds1 in connection with a continent extending both northward and southward from the equator over many degrees of latitude1 such as obtains on the western continent1 is abundantly able to create extensive depressions and elevations on the ocean's surface1 and thus cause vast streams of water to move by gravity from the high sea-levels to the low sea-levels2 and in this way the tropical waters have been moved during past ages1 and to a considerable extent are now moved far into the northern and southern seas4 ,this transfer of the ocean waters is the main cause of a temperate climate being enjoyed by countries situated in the high latitudes at this age4 ,but1 in order that the tropical currents should be able to flow into the high latitudes1 in quantities sufficient to cause all lands and seas situated in such latitudes to enjoy a mild climate1 it would be necessary that the land should extend unbroken1 or nearly so1 from the arctic to the antarctic circles4 ,thus1 with a continent of such vast extent1 the westerly winds would blow the surface waters of the ocean away from the eastern shores in the high latitudes1 and so cause extensive low sea-levels2 while the easterly winds of the torrid zone would heap the surface waters of the ocean against the eastern tropical shores of the continent4 ,consequently1 the warm waters of the tropical high sea-level would be moved by gravity to the low sea-levels of the high latitudes1 even to the arctic and antarctic regions1 and thus afford them a mild climate4 ,in this way we account for the mild climate enjoyed on lands and seas within the high latitudes during the warm epochs anterior to the glacial periods4 ,as the western continent is the only land that extends unbroken from the equator to the cold latitudes of both hemispheres1 thus affording an opportunity for the prevailing winds to move the tropical waters into the high latitudes1 ,i will call attention to that portion of the continent which extends far southward into the southern ocean1 where the winds and ocean currents have the greatest range and power to affect the climate on different parts of the globe4 ,here we see ,south ,america separated from the antarctic continent by a wide channel of deep water1 where the westerly winds blow with great force4 ,the space now covered by this interesting channel1 owing to its being situated in the high southern latitudes1 must have been occupied by a channel of comparatively small capacity1 or else an isthmus of low land uniting the southern portion of ,south ,america with the antarctic continent during the warm epochs when the beds of the ancient seas of the northern hemisphere contained a considerable portion of the water now swelling the southern ocean4 ,therefore1 the obstructions which separated the ,pacific ,ocean from the ,south ,atlantic furnished opportunity for the westerly winds to force the surface waters of the sea away from the leeward side of such obstructions1 causing a vast low sea-level1 sufficient to attract the tropical waters heaped against ,brazil by the trade winds into the southern seas in adequate quantity to cause a mild climate throughout the antarctic regions through long periods of time4 ,recent discoveries have proved that these high southern latitudes have been subject to great changes of climate4 ,according to the reports from the ,dundee whalers1 while searching for seal in the icy seas that surround the ,south ,shetlands1 they met with the ,norwegian ship 8,jason10 ,captain ,larsen1 who had traced the eastern shore of ,graham ,land to #fh south latitude1 noting two active volcanoes4 ,the same mariner brought from ,seymour ,island fossil shells and coniferous wood of the ,tertiary epoch4 ,these furnish sufficient evidence to show that a warmer climate once prevailed there4 ,at the commencement of the glacial age the obstructions which separated the ,south ,pacific from the ,south ,atlantic had become deeply submerged by the sea1 which may have been caused by a tendency of the ocean's waters to move southward or by a comparative small movement in the earth's crust4 ,but1 on account of the stability of the crust of the earth during times so late as the glacial epochs1 the submergence of this southern region was probably owing to the movement of the ocean's waters from the northern hemisphere into the southern hemisphere1 which appears to have been brought about mostly through the agency of the great prevailing winds2 for it seems to have happened that the prevailing winds on account of the disposition of the lands and seas were able to move more of the ocean waters southward than they moved northward during the age preceding the glacial periods4 ,the waters thus slowly and gradually forced into the high southern latitudes must have deprived the northern hemisphere of their heaviness1 and added their weight to the southern hemisphere4 ,therefore1 the waters moved southward could not all be returned to the seas of the northern hemisphere by gravity1 for the reason that the earth's centre of attraction would change in accordance with the weight of water moved from the northern hemisphere into the southern4 ,it will thus be seen that1 while the northern seas were drained or became shallow1 the augmented southern oceans deeply submerged the region south of ,cape ,horn1 thus widely separating the western continent from the antarctic lands4 ,although the south-east trade winds on the eastern sides of the ,atlantic and ,pacific ,oceans extend further northward than the north-east trade winds extend southward1 owing to the heated tropical shores north of the equator being more extensive than such lands south of the equator1 still1 on account of the general weakness of the south-east trade winds at the equator1 and also because of the obstructing northern lands1 they have during remote times1 and at this age1 been largely prevented from impelling the surface waters of the sea into the northern latitudes in opposition to the brisk north-east trades4 ,furthermore1 on account of the widening of the oceans as they extend southward1 the surface currents setting in the latter direction have more broad and easy passages than the great currents setting northward4 ,moreover1 the great currents setting southward on the western sides of the oceans south of the equator are also much assisted during the southern summer months by the strong north-east monsoons which prevail along the east coast of equatorial ,africa and the east coast of ,south ,america as far as the latitude of #cj south4 ,the ,south ,african current is impelled northward by the trade winds down the south-western coast of ,africa2 but it is debarred from entering the northern latitudes by the ,guinea currents1 and so turned away into the south equatorial current which flows into the ,brazilian stream4 ,the ,gulf ,stream is much obstructed in its northern movement by the narrow ,florida channel and the opposing arctic currents1 and also by the trend of the ,north ,american coast eastward2 while its return current on the eastern side of the ,atlantic has a much less obstructed passage in its southern movement1 and1 while on its way past the ,azores and ,madeira ,islands1 is largely assisted by the prevailing winds4 ,the ,brazil current1 with the impelling force of a strong north-east monsoon during the summer season1 has no obstruction whatever in its southern passage until it meets with an offshoot from the great drift current of the southern ocean4 ,and the same favorable conditions are obtained by the great currents setting southward on the western sides of the ,south ,pacific while on their way to the low sea-levels east of ,southern ,australia and ,new ,zealand4 ,that portion of the equatorial stream of the ,pacific which continues west across the ,indian ,ocean finds no open passage to the northern seas4 ,consequently1 it turns south along the east coast of ,africa into the southern seas4 ,therefore1 this current1 in connection with the great currents setting southward east of ,australia1 offsets the great ,humboldt current setting north along the coast of ,peru4 ,in the ,north ,pacific the ,japanese current setting northward is obstructed by the narrowing of the ocean2 while its return current on the ,american side has a constantly widening ocean on its passage southward1 and also favorable winds to impel the surface waters toward the equator4 ,still1 with all the facilities above mentioned for the movement of the ocean waters into the southern latitudes1 it is probable that since the shallow seas of the northern hemisphere were drained1 or much diminished1 the prevailing winds have not possessed sufficient force to further augment the southern seas1 because of the superior weight of the land in the northern hemisphere compared with the lands south of the equator4 ,it will appear to those who attribute the rotation of the earth as being the main cause of ocean currents that ,i am too much given over to the wind theory4 ,but ,i have reason to believe1 as ,dr4 ,croll has asserted1 that 8the winds are the principal cause of the ocean currents1 and are not due to the trade winds alone1 but to the general impulse of the prevailing winds of the globe40 ,dr4 ,croll also declares that 8all of the principal currents of the globe are moving in the exact direction which they ought to move1 assuming the winds to be the sole impelling cause40 ,those who think that the rotation of the earth is the real cause of the movement of the great surface currents of the sea should explain in some reasonable way why the ,agulhas current turns west into the ,atlantic from the ,mozambique stream1 and why the ,guinea current turns to the east from the main tropical current of the ,north ,atlantic2 for it seems that these two great currents move in direct opposition to the rotation theory1 while at the same time many things go to show that they receive their motion from the winds4 ,this view of the question will receive further attention in succeeding pages4 ,it is the opinion of some writers that a difference of temperature and density between the waters of the polar latitudes and the torrid zone is the principal cause of the movement of the surface waters of the ocean from the equatorial latitudes toward the polar seas1 and so returned in under-currents2 and this is a favorable factor for assisting the winds on some parts of the sea1 especially in aiding the ,brazil current in moving the surface waters from the high sea-levels abreast ,brazil1 and the equatorial calm belt of the ,atlantic into the southern ocean1 and also for favoring the surface currents setting southward on the western sides of the ,south ,pacific and ,indian ,oceans4 ,yet1 whatever gravitating force it may possess for assisting the above-named currents1 it would also act against the impelling force of the trade winds1 while they were drifting the surface waters northward toward the equator on the eastern sides of the several oceans1 and also to retard the returning surface currents1 while being drifted by the winds southward on the eastern sides of the ,north ,atlantic and ,north ,pacific4 ,therefore1 while it would seem to favor the winds in their work on the one hand1 it would act as an opposing agent on other parts of the ocean4 ,still1 the difference of temperature between the tropical and antarctic seas probably does act in opposition to the wide and brisk trade winds on the eastern sides of the great oceans south of the equator1 and so prevents their impelling the surface waters northward to a great extent2 and this seems to be one great cause of there being less surface water moved northward than southward over the greatest oceans of the globe4 ,the theory that the difference of density caused by the difference of temperature between the polar seas and the equatorial oceans made under-currents to flow from the polar latitudes1 and meet in the equatorial seas1 can only be carried on in the ,atlantic ,ocean1 and in a comparatively less perfect way in the ,pacific ,ocean1 and not at all in the ,indian ,ocean4 ,the ,north ,atlantic being open to the ,arctic ,ocean1 a portion of the ,gulf ,stream waters that enter it from the north-west of ,europe do sink and return southward in under-currents2 and the cold waters which pass down the east and west coast of ,greenland also sink under the ,gulf ,stream while on their southern movement4 ,the meeting of these arctic currents with the cold under-currents from the antarctic seas in the tropical zone is probably one cause of their cold waters rising near the surface of the sea in the torrid latitudes of the ,atlantic2 and the same conditions probably obtain in a somewhat less degree in the ,pacific ,ocean4 ,yet it appears that the cold waters of the ,antarctic occupy the largest space in the tropical zone1 even in the ,north ,atlantic4 ,dr4 ,carpenter1 in his lectures on ,ocean ,currents1 speaks of meeting with antarctic water so far north as the latitudes of the ,west ,india ,islands2 and he also says that all of the ,pacific ,ocean at its depths is supplied from the ,antarctic ,ocean1 as are the cold under-waters of the tropical ,indian ,ocean1 which extend over twenty degrees north of the equator4 ,thus1 from what we can learn of the antarctic under-currents1 they seem to show that they are not wholly attracted northward on account of the difference of temperature between the antarctic and the tropical oceans1 but partly because of more surface water being moved southward by the prevailing winds than they are able to move northward4 ,and it appears that1 if through the winds1 combined with the difference of temperature between the antarctic seas and the equatorial waters1 and also because of the oceans widening toward the south1 more surface water is being carried southward than northward1 the waters of the under-currents so caused must rise toward the surface in the latitudes from which they were first removed4 ,having called attention to the fact that the prevailing winds are not able at this date to augment the southern ocean waters from the scanty northern seas1 because of the preponderance of northern lands1 still there is reason to believe that even now1 owing to the form of continents and oceans1 and the attraction of the tropical surface waters into the ,antarctic ,ocean because of the difference of density between the warm and cold seas1 the prevailing winds of this age are able to force more of the surface waters of the sea southward than they force northward2 but1 owing to the superior weight of the land in the northern hemisphere1 the surplus surface water forced into the southern seas is returned by gravity after being cooled by the antarctic ice1 and so adding to the deep under-currents which flow with a sluggish movement over the bottom of the sea into the tropical and northern temperate latitudes4 ,and in this way the northern oceans are maintained at their present sea-level4 ,the cold under-currents are probably assisted in their northern movement by whatever difference there may be in the density of the antarctic waters over the bottom waters of the equatorial seas4 ,but1 as such currents extend into the northern tropical latitudes of the northern hemisphere1 it seems that the winds are the main cause of the under-currents which carry so much antarctic cold into the northern tropical seas1 because the winds have forced an undue proportion of ocean surface water southward1 to be attracted northward in under-currents by the preponderating northern lands4 ,yet1 notwithstanding the superior weight of land in the northern hemisphere1 it appears that there have been periods when there was somewhat more water in the oceans of the southern hemisphere than now2 for it is reported that a portion of the low lands of ,australia show traces of having been submerged during late geological times4 ,this may have happened through an increased weight in the antarctic glaciers1 which have in past ages1 and probably may in future epochs1 cause more of the ocean waters to be attracted southward than now obtains4 ,but it is probable that an increase of southern ice would be largely counterbalanced by the accumulation of ice on northern lands4 ,yet it appears certain that since the ,tertiary epoch the waters of vast shallow seas have been moved from the northern hemisphere into the southern4 ,the dry beds of the ancient northern seas encourage this opinion1 while the comparatively small area of southern lands serves to support such views4 ,still1 during the ages prior to the glacial periods1 while the low lands of the northern hemisphere were covered by the sea1 the wide shoal channels which submerged the lower portion of ,north ,america afforded convenient passages for the surface waters of the ocean in their northern movement1 and so prevented the oceans of the southern hemisphere from gaining undue preponderance4 ,hence long geological ages passed away before the winds were able to force more of the ocean waters southward than they could move northward1 and thus augment the southern ocean from the waters of the northern seas4 ,but the slow growth of such immense marine deposits in the shallow seas as are found in the ,florida ,peninsula and other portions of that region was at length sufficient to greatly obstruct the passage of the ,gulf currents in their northern movement1 and thus cause conditions which enabled the winds to force more of the ocean waters southward than they could move northward after the close of the ,tertiary epoch4 ,mr4 ,alfred ,r4 ,wallace says in 8,island ,life0 that the seas in the northern hemisphere during the ,tertiary period covered a much larger area than now1 and extended across ,central ,europe and portions of ,western ,asia1 and the ,arctic ,ocean was enlarged4 ,as it is not likely that any portion of the waters of the sea have been absorbed by the earth during the late epochs in the world's history1 therefore the ocean waters have not diminished except during cold periods1 when the water evaporated from the sea was converted into ice1 and1 eventually1 again returned to the sea4 ,thus it necessarily follows that1 when the seas of the northern hemisphere contained a much larger portion of the waters of the globe than at this age1 the seas of the southern hemisphere must have contained proportionally less4 ,consequently1 during such times a portion of the shoal seas of the high southern latitudes must have been dry land4 ,therefore1 this must have been the condition of the shallow sea basins in the region of ,cape ,horn4 ,mr4 ,wallace also says that 8many peculiarities in the distribution of plants and some groups of animals in the southern hemisphere render it almost certain that there has sometimes been a greater extension of antarctic lands during ,tertiary times40 ,and he also asserts that the great ocean basins have not changed1 and that the form of continents has been permanent4 ,it will thus be seen that it was through the movement of the ocean's waters southward that the low lands south of ,cape ,horn were covered with water previous to the frigid periods1 and so caused the wide separation between the western continent and the antarctic lands4 ,the ,cape ,horn channel thus enlarged1 the continuous mildness of the high southern latitudes which possessed the earlier ages came to an end1 and gave place to alternate epochs of frigid and mild weather4 ,for it appears that it is owing to the creation or enlargement of the ,cape ,horn channel that it is possible for frigid periods to be brought about1 for the reason that its enlarged space of water prevents the westerly winds from maintaining a great low sea-level in the higher latitudes of the southern ocean2 for1 whenever the capacity of the ,cape ,horn channel is enlarged1 the westerly winds1 instead of maintaining a low sea-level on the ,south ,atlantic1 employ their force in impelling the surface water of the southern seas around the globe4 ,and this work the strong westerly winds of the high southern latitudes have always accomplished whenever the ,cape ,horn channel was widely open1 and this is what the winds are doing at this date4 ,therefore1 such waters of the torrid zone as are moved southward from their high sea-level1 caused by the trade winds abreast the ,brazilian coast1 are largely turned away from the high southern latitudes4 ,it is true1 even with an enlarged ,cape ,horn channel1 they can always flow along the ,south ,american coast to an inferior low sea-level1 caused by the westerly winds blowing the surface waters of the sea away from the coast of ,argentine and ,patagonia2 but on gaining that region they meet the cold ice-bearing currents which turn away east of ,cape ,horn from the great southern drift current to gain the same low sea-level which attracts the ,brazil water4 ,consequently1 the ice-bearing currents from the south1 which branch off from the great southern drift current1 are able to largely turn away the warm ,brazil current from the higher southern latitudes2 and1 furthermore1 the great southern drift current which passes through the ,cape ,horn channel1 and so onward around the globe1 also partly turns away the ,mozambique current as well as the ,east ,australian current1 and so largely prevents their waters from warming the southern seas4 ,therefore1 it is evident that1 whenever the ,cape ,horn channel obtains sufficient capacity to give an independent circulation to the southern ocean1 the conditions are favorable for the increase of cold in the southern latitudes4 ,for it is because of the large exclusion of the tropical waters from the southern seas that ice-sheets have been able to form in early periods and in later epochs on the antarctic lands1 and store away the annual frosts for thousands of years1 and at the same time furnish icebergs sufficient to chill the waters of the southern temperate oceans1 and consequently make cold such of the surface waters of the sea as are forced into the southern latitudes by the winds in surface currents1 and so returned to warmer seas in cold under-currents1 and thus with such frigid combinations bring about cold periods4 ,thus it appears1 as ,i have previously shown1 that it is owing partly to there being more of the surface waters of the sea forced southward by the prevailing winds than they impel northward that the cold under-currents are maintained2 but it also requires an independent circulation of the southern ocean1 such as ,i have pointed out1 to cool its surface waters before they can sink and form cold under-currents4 ,and there is reason to believe that such cold under-currents are more efficient in lowering the temperature of the temperate and tropical oceans than even the icebergs which such under-currents move into the temperate seas4 ,and1 when it is considered that the cold antarctic under-currents fill the depths of the ,pacific and ,indian ,oceans in the northern hemisphere1 and also largely the tropical depths of the ,north ,atlantic1 ,i am led to believe that the frigid conditions of the ice age were concurrent in the northern and southern hemispheres4 ,the main reasons for such belief ,i will explain in the following chapter4 ,after the foregoing explanations1 showing how frigid periods are brought about through the independent circulation of the southern ocean surface waters1 it is evident that1 whenever through a slow natural process the ,cape ,horn channel is closed1 a great change is wrought in the circulation of the southern ocean4 ,for instead of the westerly winds blowing the surface waters of the southern seas constantly around the globe1 and so turning away and preventing the entrance of the tropical currents into the high southern latitudes1 the strong westerly winds1 whenever the ,cape ,horn channel is closed or greatly obstructed1 would blow the surface waters away from the ,atlantic side of the closed channel1 and so cause a great low sea-level1 sufficient to attract the ocean waters of the tropical high sea-level abreast ,brazil well into the southern seas4 ,therefore1 it is important to trace nature's slow methods of closing the wide ,cape ,horn channel at the perfection of an ice age4 ,in my previous explanations on the subject ,i have thought that1 should the southern seas have remained at or near the same sea-level as now1 through an ice period brought about in the manner ,i have described1 ice-sheets would accumulate on the antarctic continent1 and also on the southern lands of ,south ,america1 sufficient to flow out into the sea and close the ,cape ,horn channel4 ,but further consideration shows the impossibility of the southern seas having maintained their present sea-level during the growth of frigid epochs which have left such ample traces of glaciers having extended widely over the lands of the high latitudes of both the northern and southern hemispheres4 ,for it appears that the larger areas of land in the northern latitudes1 embracing wide continents and large islands1 must1 during the growth of a frigid age1 have increased the spread of glaciers many times greater in extent than could be obtained on the smaller lands of the high latitudes of the southern hemisphere4 ,for it is evident that the water evaporated from the sea and deposited in snow on the large continents and islands of the high northern latitudes during the growth of an ice period would1 while thus diminishing the ocean waters1 greatly increase the weight of northern lands4 ,therefore1 the waters of the diminishing seas of the southern latitudes would be attracted into the northern oceans in opposition to the prevailing winds4 ,thus it appears that the ,cape ,horn channel would be too much reduced at the perfection of an ice age to afford an independent circulation for the southern ocean1 even without being filled by glaciers to the extent ,i have pointed out in previous essays4 ,still1 to whatever dimensions the ,cape ,horn channel might be reduced at the perfection of a frigid period1 the enlarged shores bordering its diminished waters would be covered by heavy glaciers that would flow into the shrunken strait1 and so close it effectually4 ,thus the reduction of the ,cape ,horn channel during the advance of an ice age seems1 on close consideration1 to be a simple operation of nature1 which in the normal course of events must have taken place4 ,as the closing of the ,cape ,horn channel has been considered by reviewers the weak and questionable point in preventing my views from gaining acceptance1 it becomes necessary to be explicit concerning the manner in which the ,cape ,horn channel has in past ages been obstructed4 ,according to the charts prepared by ,john ,james ,wild1 the middle portion of the strait is represented as being over a thousand fathoms in depth2 but1 as far as ,i know1 its true soundings have never been determined4 ,the deep portion of the mid-channel is described as being narrow when compared with its whole breadth from ,cape ,horn to the antarctic continent4 ,and1 when it is considered1 with the growth of an ice age1 how much of the ocean waters would be stored in the vast ice-sheets of the northern hemisphere1 and consequently because of their weight a large portion of the diminished southern oceans would be attracted into the northern seas1 it seems that the bottom of the shoaler waters of the ,cape ,horn channel1 which now comprise so large a portion of its breadth1 would be raised above the surface of the sea4 ,the one-hundred-fathom depth south of ,cape ,horn1 now supposed to extend from longitude #gj west to #ee west1 and southward to the latitude of #eg1 would be a land supporting heavy glaciers for six hundred miles along the north side of the reduced channel during the advanced growth of a frigid age2 and the same conditions would be obtained in the vicinity of the ,south ,shetland4 ,and when1 in addition1 we contemplate the great snow-fall of that region1 and the consequent gathering of glaciers which would occur on the widened shores of the lessened channel1 and the certainty of their flowing into the diminished strait1 together with the immense icebergs of such an age grounding in the shoaled waters1 it seems that the complete obstruction of the reduced channel would be accomplished4 ,while contemplating the conditions that would obtain while the ,cape ,horn channel was being reduced1 it will be seen that the independent circulation of the icy southern ocean would be carried on to a considerable extent even after the narrowing strait was no longer able to afford space for wide drift currents1 for the reason of the strong current that would be caused on account of the high ocean-level maintained by the westerly winds on the ,pacific side of the diminishing channel1 and the great low sea-level that would take place on its ,atlantic side4 ,still1 as previously shown1 it seems that during an advanced stage of the frigid epoch1 the heavy glaciers from the enlarged northern and southern shores of the shrunken channel1 together with the ponderous icebergs1 blocking its waters1 the closing process would at last be speedy and effective4 ,and on further consideration it might be said that a channel of much less width and depth would not have been of sufficient capacity to have caused ice periods so wide-spread as those that have left their traces on the continents and islands of the globe1 for the reason that the independent circulation of the southern ocean would not have been sufficiently complete and long continued to have brought such world-wide cold periods to perfection4 ,with the ,cape ,horn channel closed1 as above explained1 there would be1 as ,i have asserted1 a great change wrought in the circulation of the southern ocean2 for instead of the westerly winds blowing its surface waters constantly around the globe1 and so turning away and preventing the entrance of tropical currents into the higher latitudes1 the strong prevailing westerly winds would blow the surface waters of the sea from the ,atlantic side of the closed ,cape ,horn channel1 and so cause a great low sea-level1 sufficient to attract the ocean waters of the tropical high sea-level abreast ,brazil well into the southern seas4 ,the winds of the southern westerly wind-belt being stronger in that region than on any other portion of the globe1 consequently they are able to do nearly as much work while drifting surface water as the belt of westerly wind of greater width on other parts of the southern seas4 ,thus a person who has had a long experience with the forcible westerly winds of the southern ocean can well understand their ability for disturbing the ocean waters in the latitudes of the ,cape ,horn channel4 ,the drift currents of this region are moved by the winds and waves from one to four miles an hour4 ,therefore1 with the ,cape ,horn channel closed1 there is nothing more certain than that the westerly winds would be able to cause a vast low sea-level on the ,atlantic side of the closed ,cape ,horn strait1 and that the waters of the high tropical sea-level abreast ,brazil would be attracted to its wide depression1 as shown on map ,no4 #a4 ,the tropical waters thus attracted far southward would be cooler than the tropical waters of to-day1 owing to the great amount of cold imparted to the ocean by the numerous icebergs of a frigid age4 ,still1 they would begin the slow process of raising the temperature of the southern ocean1 and would in time carry sufficient heat into the southern regions to melt the ice from all southern lands2 for1 in addition to the ,brazil currents1 the waters of the high sea-level of the tropical ,indian ,ocean which pass southward down the ,mozambique channel would reach a much higher latitude than during periods when the ,cape ,horn channel was open4 ,the ice periods of the northern and southern hemispheres being concurrent1 a condition which ,i shall explain in another chapter1 makes it obvious that during the melting of the glaciers from the antarctic continent and other southern lands the depleted ,cape ,horn channel could not gain sufficient capacity to give an independent circulation to the southern ocean during the melting of the southern ice-sheets1 on account of the diminishing heaviness of the antarctic ice and the greater weight of the extensive glaciers and augmented seas of the northern latitudes4 ,consequently1 it seems that the southern seas would continue in a lessened state while the glaciers were being melted from the northern hemisphere1 as was the case during the melting of the ice from the southern hemisphere2 and1 furthermore1 during such times the glaciers which overrun all the low lands and shoal waters of the ,cape ,horn region would1 on account of their position being to the windward of the tropical currents1 be the last great mass of ice to melt from the southern hemisphere4 ,therefore1 it seems that the ,cape ,horn channel would continue closed or greatly obstructed while the glaciers were being melted from the lands of both hemispheres4 ,thus at length a mild climate would extend over the globe1 and so remain until the prevailing winds slowly forced the surface waters of the sea into the southern ocean in the manner explained in previous pages1 thus filling the ,cape ,horn channel to its present capacity1 and again restoring the independent circulation of the southern ocean4 ,while contemplating the conditions that would obtain during the melting of the ice from the antarctic lands1 it will be seen that the tropical waters attracted to the great low sea-level to the leeward of the closed ,cape ,horn channel would eventually enter the great bight of the antarctic continent to the eastward of ,graham ,land1 where ,captain ,weddell sailed to the latitude of #gd south4 ,this deep gulf1 owing to its situation1 would receive the full impact of the southern movement of the tropical currents2 and1 as the warm waters spread over the wide sea-level1 the westerly winds would convert them into a drift current1 and under such conditions would be driven along the shores of the antarctic continent1 past the ,south ,indian and ,pacific ,oceans1 and eventually1 after undergoing a cooling process from the long icy passage1 be forced against the ,pacific side of the closed ,cape ,horn channel and the western ,patagonian coast4 ,while regarding the circulation of the sea during an ice age1 it may be said that the ocean's being composed of brine was the cause of its waters being able to circulate in frigid latitudes where fresh water would congeal4 ,consequently1 this is one of the reasons why successive periods of frigidity and mildness have been brought about2 for with an ocean of fresh water1 repeated epochs of cold and warmth could not have occurred1 because a sea composed of fresh water would have congealed while circulating in the high latitudes during a frigid age4 ,therefore1 it required a sea of brine to maintain a liquid state during the low temperature of an ice period4 ,for1 while the cold of a glacial age increased1 the saltness of the sea increased also1 because of the great amount of fresh water evaporated from the ocean1 and stored in ice-sheets on the great continents and islands of the globe4 ,thus the briny sea was maintained in a liquid state1 while washing vast ice-fields and glaciated shores and floating the numerous icebergs of a freezing age4 ,the cold which radiated from such ice-bound seas must have been severe2 but meanwhile the evaporation from the ocean was much reduced1 while the saltness and coldness of the sea increased1 and so prevented the ice of a glacial period from gaining invincible proportions before the independent circulation of the southern ocean was arrested4 ,therefore1 the remaining warmth of the tropical waters after gaining free access to the antarctic latitudes was able to overcome the accumulated cold of that frigid region4 ,at this date the observant navigators who have visited the antarctic seas report that the surface currents above the latitude of ,cape ,horn1 while being drifted eastward by the prevailing westerly winds1 also set toward the antarctic ice cliffs1 as shown on map ,no4 #b4 ,the reason why this southerly set of the surface currents becomes noticeable above the latitude of #ee south is because the tropical currents which set southward from the torrid latitudes on the western sides of the ,atlantic1 ,indian1 and ,pacific ,oceans1 although largely turned away from the high latitudes by the westerly winds and drift currents1 are also able to send sufficient water into the great belt of westerly winds to furnish water for the deep under-currents setting northward from the antarctic shores4 ,thus the surface waters moving from the north in order to gain the higher latitudes1 after entering the westerly wind-belt1 are moved in drift currents by the impelling winds easterly over many degrees of longitude1 and also at the same time slowly southward among the cooling icebergs1 because of the attraction caused by the difference of temperature and density between the northern drift waters and the icy seas of the antarctic ice barrier4 ,consequently1 the gradual movement of the surface waters of the westerly wind-belt southward before entering the higher latitudes is not generally apparent2 for it is after they enter latitudes where the globe becomes much reduced in circumference that their southern movement in the contracted seas becomes more noticeable4 ,the impact of this southerly current1 which finds its outlet in deep under-currents1 and retards somewhat the increase of ice on the southern continent at this date1 also largely prevents the small icebergs and field-ice from floating northward1 away from the antarctic ice barrier2 for it is such large icebergs as penetrate the deep under-currents that are the best able to move into the more temperate latitudes4 ,from the above explanations it will be seen that the impact of surface water against the antarctic ice barrier when the ,cape ,horn channel was closed would greatly assist the tropical waters attracted to the great low sea-level to the leeward of the obstructed strait to wash the antarctic shores while being drifted eastward by the westerly winds over the southern ocean against the ,patagonian coast and the ,pacific side of the closed channel1 and there causing a high sea-level4 ,this movement of the winds and currents encircling the antarctic continent is shown on map ,no4 #a4 ,the vast1 high sea-level caused by the westerly winds drifting the surface waters against the ,patagonian coast would obtain a much higher plain1 were it not that so much of the water of the great drift current was required to feed the antarctic under-current which constantly sets northward from the antarctic shores2 yet it would be sufficient to greatly increase the volume of the ,humboldt current1 which would flow in the same direction it now flows1 down the ,south ,american coast to the equatorial latitudes1 where it would become the main source of the great equatorial stream1 and thus offset the increased southward flow of the equatorial waters through the ,brazil and ,mozambique streams4 ,the equatorial stream1 with its increased volume1 would also move1 as it moves to-day1 across the ,pacific2 and1 on gaining the western side1 after sending off large streams to the northern and southern latitudes1 it would pass through the ,east ,india passages into the ,indian ,ocean1 where it would be drifted westward by the trade winds and cause a high sea-level abreast the east coast of ,africa1 and so become the source of the great ,mozambique current1 which would flow southward along the east coast of ,africa1 and1 with the ,cape ,horn channel closed1 would gain a much higher latitude than it would with the channel open4 ,at this age1 when the continuation of this great equatorial stream gains the latitude of the ,cape of ,good ,hope1 its waters are largely turned eastward by the great drift current of the southern ocean4 ,still1 a considerable portion of its waters turns toward the west1 forming the ,agulhas current1 which flows around the ,cape of ,good ,hope into the ,atlantic1 where it mingles with the cooler currents which branch off from the great southern drift current2 and so1 in connection with the latter1 it is attracted to the low sea-level caused by the south-east trade winds abreast the south-western coast of ,africa1 and from thence moved as a drift current by the trade winds to the equatorial ,atlantic and coast of ,brazil4 ,thus it will be seen that the ,agulhas current1 even with the ,cape ,horn channel in possession of its present wide capacity1 serves to retard somewhat the advance of a cold period4 ,the ,agulhas current at this date also partly serves to replenish the water which is forced from the ,south ,atlantic by strong westerly winds into the ,southern ,indian and ,southern ,pacific ,oceans4 ,for it appears that more water is now removed by such winds from the ,south ,atlantic than enters it from the ,south ,pacific1 even through the enlarged ,cape ,horn channel of this date2 and this fact seems to favor an impression that a portion of this enlarged channel existed prior to the glacial periods1 but with its waters so much reduced as to be unable to give the southern ocean an independent circulation sufficient to exclude the tropical currents from reaching the high southern latitudes in adequate volume to maintain a mild climate in the southern hemisphere4 ,for previous to the glacial age1 with little or no ice gathered on the antarctic lands1 it seems that a strait possessing one-half the capacity of the ,cape ,horn channel of the present age could not prevent the ,brazil current and the ,agulhas stream from flowing into the southern ocean in quantities sufficient to make it impossible for glaciers to form on southern lands4 ,thus it is probable that a reduced channel separated the western continent from the antarctic lands even in the mild eras previous to the glacial epochs4 ,the ,cape ,horn channel1 at the present age1 with a capacity sufficient to largely maintain an independent circulation for the southern ocean1 is still only one-third of the breadth of the westerly wind-belt of the southern seas4 ,therefore1 the drift currents do not all pass through it from the ,pacific into the ,atlantic4 ,consequently1 a considerable portion of the drifted water turns northward west of ,cape ,horn1 and so forms the ,humboldt current4 ,the ,agulhas stream1 which even now assists in replenishing the ,south ,atlantic with tropical water1 would1 during the perfection of a glacial period1 with the ,cape channel closed1 be a much stronger stream than it now obtains with the ,cape channel possessing its present enlarged capacity1 for the reason that the ,south ,atlantic waters would continue as now to be forced eastward by the westerly winds1 while they could not be replenished1 as they are to-day1 directly from the ,south ,pacific4 ,consequently1 the waters of the ,south ,atlantic ,ocean would be correspondingly reduced4 ,such conditions alone would greatly increase the volume of the ,agulhas stream at the culmination of a frigid age4 ,therefore1 the work of subduing a frigid period in the southern hemisphere after the ,cape ,horn channel was closed would not rest on the ,brazil current alone1 but also on the great equatorial stream of the ,pacific and ,indian ,oceans4 ,yet during such frigid times the sources of the equatorial stream would be greatly chilled by its two great feeders1 the ,humboldt current and the returning ,japanese current1 both of which flow down from the high latitudes and meet in the equatorial latitudes on the eastern side of the ,pacific1 thus cooling the source of the great equatorial current4 ,but this latter stream1 while on its long western passage across the ,pacific and ,indian ,oceans1 beneath a torrid sun1 with only one cold feeder from the south which approaches it along the west side of ,australia1 would1 on its long tropical journey1 be able to obtain considerable warmth1 even during an ice period1 to supply the ,mozambique and ,agulhas streams1 and so greatly assist the ,atlantic waters in bringing about a mild period4 ,still1 the process of subduing the cold of the southern latitudes would be slow1 even with the ,cape ,horn channel closed1 because of the vast collection of ice burdening the sea and land4 ,yet there were conditions that were naturally brought about to favor the process of returning warmth2 for it appears that1 when the southern ocean was made shallow because of a considerable portion of its waters having been moved into the northern hemisphere1 it will be seen that the conditions were more favorable for the westerly winds to create drift currents than would be the case on deeper seas4 ,therefore1 the high and low sea-levels caused by such winds would be greater on a shallow ocean than would occur on deeper waters4 ,thus the low sea-levels of the shallow southern sea would have strong attraction for tropical surface waters1 and so increase the thickness of its warm drift currents1 and at the same time its lessened depths would have less capacity for the storage of cold water to reduce the temperature of the under-waters of the tropical zone4 ,and1 furthermore1 when the southern ocean was shallow1 ,new ,zealand acquired a longer extension of land to the north and south4 ,consequently1 the enlarged low sea-level on its eastern side attracted more tropical water into the southern latitudes than now4 ,so1 according to the conditions ,i have pointed out1 the ice-sheets would at length melt away1 and a long period of mildness would succeed on account of the length of time it would require after the ice disappeared from the earth for the prevailing winds to move the surface waters of the augmented northern seas into the southern ocean1 and again restore its independent circulation1 and so1 after a considerable lapse of time1 bring about the geographical and climatic conditions existing at the present date1 which can be seen on map ,no4 #b1 which shows that a cold period has already made considerable advance in the southern hemisphere1 the southern continent and islands being covered with glaciers1 and the prevalence of icebergs as far north as the latitude of #ce south4 ,moreover1 when we consider that the independent circulation of the southern ocean is caused by the westerly winds blowing its surface waters constantly around the globe through the open ,cape ,horn channel1 and so largely preventing the tropical currents from entering the high southern latitudes1 and how1 in consequence1 the cold is slowly on the increase through the constant accumulation of ice on the lands and in seas of the southern latitudes1 it appears that a frigid age is slowly progressing in the southern hemisphere4 ,for it seems that continental ice-sheets should not only be able to retain their freezing temperature1 but also the mean of the low temperature in which they were formed1 for a considerable length of time1 and so impart their extreme coldness in the shape of icebergs into such seas as border on the glaciated lands4 ,it has been proved at ,point ,barrow that strata of ice and gravel can maintain a wintry temperature through the summer months4 ,captain ,g4 ,b4 ,borden1 keeper of the refuge station in that region1 states that ,lieutenant ,ray1 of the ,signal ,service1 excavated through ice and gravel to a depth of forty-one feet1 and that the lower portion of the excavation maintains a temperature #ae ,fahrenheit above zero the year around4 ,therefore1 with the probability of southern glaciers obtaining a temperature of over #ae ,fahrenheit below the freezing point1 we can well realize the frigidity imparted to the southern oceans while melting numerous immense icebergs1 and consequently will conclude that the temperature of the southern latitudes is gradually lowering4 ,the icebergs of the antarctic seas would not move northward into the temperature latitudes so readily as they now do1 were it not that the general southward set of the southern ocean currents were interrupted by the movement of northerly surface currents in the longitudes of the low sea-levels1 caused by the westerly winds drifting the surface waters of the sea from the eastern coasts of ,southern ,south ,america and ,new ,zealand4 ,for it is owing to the low sea-levels thus created1 in connection with the deep under-currents which set northward from the ice cliffs of the antarctic lands1 that many icebergs are enabled to move into the temperate latitudes1 especially to seas north-east of the ,falkland ,islands4 ,on other portions of the southern ocean above the latitude of #ee south the surface waters1 while being drifted eastward by the strong westerly winds1 also set toward the antarctic shores1 and so furnish water for the cold under-currents which set northward from that frigid region4 ,thus from such parts of the coast only the largest bergs1 which require a deep sea to float them1 are moved by the under-currents into the temperate latitudes4 ,therefore1 it happens that1 while an ice period progresses1 and the antarctic icebergs increase in size1 the more readily the cold1 deep under-currents force them into the temperate zone1 in opposition to the winds and surface currents4 ,the icebergs1 after gaining the temperate latitudes1 are moved more or less eastward by the westerly winds and drift currents1 and so are scattered over the southern temperate oceans1 where the melting bergs impart whatever coldness they were able to store up while forming in the antarctic regions4 ,the low sea-levels caused by the westerly winds to the leeward of ,new ,zealand and to the leeward of ,argentine1 not only cause the ice-bearing currents to set northward1 but they also cause the tropical currents to make considerable inroads into the high southern latitudes4 ,this is the reason why the lands are less burdened with ice on the antarctic shores opposite ,cape ,horn than on other parts of that glaciated continent4 ,the tropical currents which turn southward east of ,new ,zealand largely mingle their waters with the great southern drift current1 and so are carried through the ,cape ,horn channel4 ,owing to this cause1 the antarctic lands abreast ,cape ,horn are less burdened with ice than other portions of the antarctic shores4 ,thus1 were it not for this penetration of warm waters southward1 the antarctic coasts south of ,cape ,horn1 because of the great snow-fall of that region1 would obtain heavier glaciers than other portions of the southern continent4 ,but the time is slowly coming when1 with a lower temperature1 the ice-sheets on the lands in the vicinity of the ,south ,shetlands will attain greater thickness than the glaciers on other shores of the antarctic continent4 ,hence it appears that1 when the several agents for producing and distributing cold in the southern latitudes are taken into consideration1 the immense and continuous storage of ice on the southern lands1 which adds to the wide-spread fleet of icebergs that float the southern temperate seas1 and also the vast movement of cold antarctic water into the temperate and tropical oceans in deep under-currents1 combined with the increasing coldness of the westerly winds1 are now slowly bringing about in the southern hemisphere a period of frigidity4 ,,chapter ,,ii4 ,,how ,,ice ,,periods ,,in ,,the ,,northern ,,hemisphere ,,are ,,brought ,,about4 ,a large number of geologists are of the opinion that during the whole of the ,tertiary period the climate of the northern temperate and arctic latitudes was uniformly warm1 without a trace of intervening frigid periods4 ,i have before explained why the climate was made warm in the southern hemisphere during the ,tertiary epoch1 and how on the closing of that age1 and subsequently1 a considerable portion of the ocean waters had moved from the northern hemisphere into the southern4 ,therefore1 the northern seas during ,tertiary times covered a much larger area than have obtained during periods following that mild epoch4 ,so1 when the low lands of ,europe were submerged1 the ,baltic1 ,caspian1 and other neighboring seas1 now land-locked1 were a portion of an enlarged ,atlantic4 ,consequently1 the westerly winds blew over a much wider ,north ,atlantic than during the later periods4 ,thus the high sea-level caused by such winds on its ,european side was greater than has since been obtained with the ,atlantic of less breadth4 ,this high sea-level1 composed largely of drift water from the ancient ,gulf ,stream1 had convenient access to the enlarged ,arctic ,ocean1 which then covered the low plains of ,northern ,europe and ,siberia4 ,and owing to the trend of elevated lands north-eastward1 which then formed the southern shores of the ,arctic ,ocean in those regions1 the warm waters of the high sea-level of the ,eastern ,north ,atlantic found an easy passage into the arctic seas2 for1 while they moved over the ,european and ,siberian seas to the north-east1 they had the assistance of the westerly winds well into the arctic seas1 from which position they were attracted across the ,arctic ,ocean to the low sea-level abreast ,labrador and ,davis ,strait4 ,the ,gulf ,stream of ,tertiary times comprised a much larger area than it now obtains2 for with ,florida and a large portion of the ,gulf ,states submerged1 and a wide1 shallow sea covering the ,mississippi valley and the ,great ,lake region1 the tropical waters of the enlarged ,gulf of ,mexico moved from their vast high sea-level to the low sea-level abreast ,british ,america and ,labrador1 without being confined to the narrow ,florida channel4 ,thus with an enlarged ,gulf ,stream in possession of a wide and clear passage leading northward1 in connection with a mild period in the southern hemisphere1 giving warmth to the southern oceans1 the resources of the ancient ,gulf currents for warming the northern regions were so ample and inexhaustive they were fully able to maintain a mild climate on the shores of the ,european seas1 and also on the shores bordering the ,arctic ,ocean1 during the ,tertiary epoch4 ,furthermore1 the ,humboldt current1 which had its rise in the mild southern seas of that age1 mingled its warmth with the equatorial current of the ,pacific1 which in turn gave its warmth to the ,japanese current4 ,therefore1 the latter stream under such conditions was competent to maintain a mild climate on the ,north ,pacific coasts4 ,the origin of a cold period in the northern hemisphere was largely owing to the changed condition of the northern oceans following the close of the ,tertiary epoch4 ,the movement of the ocean waters into the southern hemisphere lessened the area of the ,arctic and ,north ,atlantic ,oceans1 and brought them to their present reduced limits1 and also diminished the volume of the ,gulf currents4 ,this great geographical change1 in connection with a cold period progressing in the southern hemisphere1 and so increasing the coldness of the ,japanese current1 and the cold antarctic currents1 previously explained1 which set northward on the bottom of the sea through the torrid latitudes even into the ,north ,pacific and ,north ,atlantic ,oceans1 were altogether sufficient to cause conditions favorable for the advancement of a cold period in northern latitudes4 ,besides1 with reduced northern oceans and a diminished ,gulf current1 conditions were favorable for an independent circulation of the arctic waters1 such as is being carried out at the present time4 ,hence an explanation of the movements of the ocean waters of to-day will explain the conditions which caused the northern ice periods in times past1 as well as those to come in a future age4 ,although the conditions are such that the independent circulation of the arctic waters cannot be so well performed as the independent circulation of the southern ocean1 still the open arctic channels are able to prevent the tropical ,gulf ,stream water from largely entering the higher northern latitudes4 ,for it is certain that the prevailing westerly winds blow the surface waters of the ,north ,atlantic away from the eastern shores of ,north ,america from ,georgia to ,labrador4 ,consequently1 the low sea-level thus caused attracts the waters of the ,arctic ,ocean southward through ,baffin's ,bay and ,davis ,strait1 and likewise down the east coast of ,greenland1 thus surrounding that large island with an arctic temperature1 and so causing it to become a land of glaciers1 which are constantly launching icebergs into the sea to cool the waters of the northern oceans4 ,the tropical waters of the high sea-level of the ,gulf of ,mexico also seek the low sea-level abreast the ,american coast1 thus causing the ,gulf ,stream4 ,this great ocean current1 being the main conveyer of tropical heat into the high latitudes of the ,north ,atlantic1 calls for particular notice4 ,the great gravity currents1 of which the ,gulf ,stream is one of the most conspicuous1 are moved by small gradients4 ,hence the gradient which causes the ,gulf ,stream waters to move out of the ,florida passage is small4 ,the levellings which have been made place the surface waters of the ,gulf of ,mexico as being about one metre higher than the ,atlantic abreast ,new ,york1 the pressure of the higher ,gulf waters toward the low level of the ,atlantic being nearly equal in the narrow ,florida channel from the surface to the bottom of the stream4 ,therefore1 according to descriptions given by ,commander ,bartlett1 the warm stream moves like a river over the hard level floor of the channel2 but to the northward of the ,bahamas1 abreast ,cape ,hatteras1 the stream spreads out in fanlike form1 and flows over a bed of cold water of great depth4 ,a bed of cold water is found to cover the bottom of all the deep oceans that are accessible to the antarctic seas1 through which the cold water is mostly supplied1 as ,i have before pointed out4 ,but the cold water which underruns the ,gulf ,stream is probably furnished by the arctic waters which move down ,davis ,strait and the east coast of ,greenland4 ,the ,gulf ,stream1 as it widens and becomes more shallow1 is1 through its exposure to the westerly winds1 gradually converted into a drift current2 and in this way its surface waters are forced over abreast the shores of ,western ,europe1 where it imparts its warmth to a wide region1 and also causes a high sea-level4 ,a portion of the waters of this high sea-level turn southward to replenish the waters which have been moved by the trade winds from the eastern tropical ,north ,atlantic over into the ,caribbean ,sea and ,gulf of ,mexico1 while its northern and smaller portion mingles with the ,arctic ,ocean waters north of ,europe4 ,these latter waters1 having escaped from the westerly wind-belt1 and acquired a high sea-level1 and also made cool on mingling with the icy arctic seas1 lose a part of their bulk on becoming chilled by sinking and returning in under-currents to the seas from which they were forced by the south-westerly winds2 while the larger remaining surface waters set across the ,arctic ,ocean over to the northern coast of ,greenland1 and so down the east and west coasts of that large island to the low sea-level abreast the ,american coast1 where the cold waters not only crowd the ,gulf ,stream from the shore1 but they also sink under it1 and form the vast bed of cold water over which the ,gulf currents flow4 ,this cold underflow of water southward probably joins the deep antarctic currents south and south-east of the ,bermuda ,islands1 and returns to the tropical latitudes a portion of the water that is carried into the ,arctic ,ocean by the ,gulf ,stream4 ,there are times during the late summer and early fall months when the arctic channels are considerably obstructed by icebergs1 and the low sea-level of ,davis ,strait and ,baffin's ,bay1 with the assistance of occasional south-east winds1 is able to attract the temperate waters of the ,atlantic as far north as the ,arctic ,circle4 ,also from the same cause the icy waters which flow down the east coast of ,greenland are attracted along its southern and south-western shores into ,davis ,strait4 ,yet at the same time the icy waters which flow from ,smith's ,sound and other arctic channels move in a counter-current down the westerly side of ,baffin's ,bay and ,davis ,strait1 and so carry the icebergs and field-ice past ,labrador and ,newfoundland well on to the borders of the ,gulf ,stream4 ,and1 according to ,lieutenant ,maury1 the westerly gales of the winter months force the temperate waters of the ,atlantic1 which pertain to the ,gulf ,stream1 several degrees away from the south-east coast of ,greenland4 ,therefore1 during such seasons the surface waters of the returned arctic currents1 which flow down the east coast of ,greenland and ,davis ,strait1 are drifted past ,southern ,greenland and ,iceland1 and so onward into the arctic seas1 north of ,europe4 ,thus the arctic waters maintain an independent circulation sufficient to largely exclude the ,gulf ,stream from the arctic seas1 and surround ,greenland with an arctic temperature2 and it is on this account glaciers have formed on ,greenland and other arctic shores1 and such glaciers are probably increasing1 as every iceberg launched from the frigid lands and floated to the lower latitudes lowers somewhat the temperature of the ,north ,atlantic1 and so causes conditions favorable for larger accumulations of ice on the arctic shores4 ,yet it is probable that an ice period extending over the northern temperate zone could not be perfected by this process alone1 should the tropical and southern oceans maintain their present temperature4 ,but1 with the assistance of a frigid period in the southern hemisphere to cool the ocean waters1 and thus lower the temperature of all tropical currents1 including the ,gulf ,stream and ,japan currents1 an ice age could be brought about in the northern hemisphere equal in intensity to the glacial periods of the past4 ,and1 when we know that a considerable portion of the heat carried into the northern latitudes by tropical streams is largely derived through the mingling of the waters of such currents with the warm waters of the southern tropical oceans1 it is evident that the ice periods of the northern and southern hemispheres were concurrent2 although the culmination of the northern frigid period would be somewhat later than the perfected southern ice age1 on account of the northern seas requiring the assistance of the cold oceans of the southern hemisphere to perfect a northern ice age4 ,the small area of the northern seas1 compared with the southern oceans1 and the wide mingling of the ocean waters of the hemispheres1 make it evident that the comparatively scanty northern seas could not bring about or maintain either a frigid or mild period in opposition to the superior oceans of the southern hemisphere4 ,on the consummation of an ice period in the northern hemisphere heavy glaciers covered the larger portion of its continents and islands1 which added so much weight to the northern lands as to attract the waters of the southern oceans into the northern latitudes1 as ,i have before explained4 ,thus1 when the ice was mostly melted from the lands of the southern hemisphere1 the heavy ice-sheets that remained on the extensive northern lands would still continue to attract the warm waters of the southern seas into the northern oceans2 and in this way the ,japanese and ,gulf currents would gain a higher temperature and greater volume1 and thus add to their ability for melting the northern glaciers wherever they were able to flow1 and so hasten the growth of a mild era in the northern hemisphere4 ,and it seems reasonable to suppose that there was more water in the northern hemisphere on the ending of its ice period than at this age2 yet it appears that it was returned to the southern hemisphere during a short period by the prevailing winds in the manner which ,i have previously explained4 ,therefore1 there are but few traces of such flowage to be found in the glacial drift1 especially with the scarcity of marine life after the rigor of a frigid age4 ,an article in ,science1 ,july #e1 #ahie1 written by ,agnes ,crane1 states that ,professor ,joseph ,prestwich has recently contributed a suggestive memoir on this subject to the ,philosophical ,transactions of the ,royal ,society4 ,it treats of the evidence of a submergence of ,western ,europe and the ,mediterranean coasts at the close of the glacial period2 and in a previous paper communicated to the ,geological ,society of ,london1 in #ahib1 the author gave evidence1 deduced from personal observation1 of the submergence of the south of ,england not less than a thousand feet1 at the close of the glacial epoch4 ,since that time the flood of water which flowed all of the low lands of the high northern latitudes has been returned to the southern seas1 because of the force of the prevailing winds in connection with the great oceans which open so widely toward the south1 the force of the winds being assisted through the attraction caused by the difference of temperature in the surface waters of the vast southern temperate oceans and the antarctic seas1 and in this manner bringing about the geographical conditions of to-day which favor the return of another ice age4 ,it is said by those who attribute the great currents of the ocean to the rotation of the earth that the winds have little to do in causing such currents as the ,gulf ,stream4 ,but my impression is that the southern portion of the ,gulf ,stream waters1 after being drifted by westerly winds over abreast ,europe1 are attracted to the low sea-level in the vicinity of the ,canary ,islands1 to be moved by the trade winds toward the equatorial calm belt and the ,west ,india ,islands4 ,and during my many months' cruising over these seas ,i have had my attention directed to the singular action of the surface waters1 while being impelled by the trade winds toward the ,west ,india sea2 for during the first fifteen hundred miles of their passage they are moved by the prevailing easterly winds without much apparent resistance or unusual disturbance4 ,but on nearing the longitude of ,cape ,st4 ,roque1 and having acquired a high sea-level from which there is no easy or wide outlet1 the impelled surface waters begin to rebel against the forceful winds1 and cause a remarkable commotion in the shape of tide-rips and white-capped ripples1 which extend from the equator in a northerly direction to the latitude of about #ai north1 thus crossing the central portion of the north-east trade-wind belt1 with a breadth of over three hundred miles1 as shown on map ,no4 #b4 ,this disturbed region where the winds and waters conflict is the probable fountain-head of the ,gulf ,stream4 ,the reason why the surface waters of this disturbed portion of the ,atlantic do not flow peacefully along through the ,west ,india passages into the ,caribbean ,sea and ,gulf of ,mexico is because of their narrow outlet at the ,florida channel4 ,for it is mainly through this narrow channel that the vast waters of the tropical high sea-level are attracted to the low ocean-level of the ,western ,north ,atlantic4 ,thus it seems that the great fountain-head of the ,gulf ,stream is situated between the wide tide-rips and the ,caribbean ,islands4 ,the waters from this high ocean-level enter the ,caribbean ,sea mainly through the several passages south of ,guadeloupe2 while the northern portion of the raised waters set mostly toward the north-west1 and so unite with the eastern portion of the ,gulf currents after they enter the ,atlantic4 ,still1 the great high sea-level which presses against the ,windward ,islands1 being somewhat higher than the ,caribbean ,sea1 forces its waters through the island passages in quantities sufficient to supply the ,gulf ,stream2 and there are times when the winds are so strong and favorable that all of the passages east of ,cuba conduct water into the ,caribbean ,sea1 the cold under-waters entering the deeper channels as well as the warm surface waters4 ,yet the currents setting through these numerous channels are subject to fluctuations1 and so also is the ,gulf ,stream which they supply4 ,that portion of the high sea-level south of ,guadeloupe receives considerable assistance as a feeder for the ,gulf ,stream through being connected on the south by the great high sea-level abreast ,brazil and the great high sea-level of the equatorial calm belt4 ,the latter high level is caused by the trade winds1 which generally blow briskly down the coast of ,sahara1 and also further off shore1 and ending south of the ,cape ,verde ,islands somewhat abruptly in the equatorial calm belt4 ,the south-east trades which blow over the ,eastern and ,middle ,south ,atlantic terminate on the southern side of the calm region4 ,therefore1 the two trade winds impel the surface waters of the tropical ,atlantic from opposite directions directly toward the calm belt1 and so raise its waters above the common level of the sea4 ,this is the opinion of the writers of the ,south ,atlantic ,directory4 ,still1 it is probable that the high ocean-level of the calm belt is but slightly raised above the common level of the sea1 on account of the trade winds having to contend against the tendency of the warm tropical surface waters to move toward the polar latitudes4 ,the calm belt expanse which extends from ,africa1 where it attains its greatest width1 gradually narrows as it extends westward to the longitude of ,cape ,st4 ,roque1 where it attains its highest sea-level1 on account of the borders of its narrowing space being impelled westward by the trade winds4 ,the movement of the waters of this high ocean-level is mostly toward the west1 forming a portion of the equatorial current of the ,atlantic4 ,the reason of its western movement is on account of its raised waters being able to supply a portion of the ,gulf ,stream with water which is sent off in a westerly current along the ,south ,american coast1 west of ,cape ,st4 ,roque into the ,caribbean ,sea2 while1 on the other hand1 it joins with the great high sea-level abreast ,brazil1 and so unites with its great southern current4 ,the gradient of the high sea-level of the calm belt on its southern side probably extends south of the equator1 on account of the south-east trades being weak in latitudes near the equator2 while on the north side the north-east trades generally blow brisk and end more abruptly1 so producing a gradient of less width than that of the ,south ,atlantic side4 ,it does not appear that the seas of the high northern latitudes gain an undue proportion of the tropical ,atlantic waters1 because of the south-east trades extending north of the equator1 on account of such winds being weak1 and the waters of the high sea-level of the ,western ,north ,atlantic having narrow and otherwise obstructed passages leading to its northern seas4 ,yet the high sea-level of the equatorial calm belt is always ready1 whenever a favorable grade is formed by a monsoon or otherwise1 to run off its surplus water obtained by winds and rain2 and ,i have noticed1 while cruising in these seas1 that it happens at times during the northern winter months when the north-westerly gales drive the surface waters of the ,north-western ,atlantic toward the tropical zone1 and at the same time a strong north-east monsoon is prevailing along the southern coast of ,brazil1 the westerly currents setting past the ,amazon ,river are reversed1 and set to the south-east1 while such conditions last4 ,for1 when the summer solstice is in the south1 and the north-east monsoon moves southward along the coast of ,brazil1 much equatorial water moves off in that direction2 and during the same season the cooled ,sahara has an outward flow of air toward the south1 which moves more or less water from the coast of ,guinea1 which is easily accomplished1 because the warm surface waters of that coast are inclined to join with the south equatorial stream4 ,consequently1 the waters move from their high sea-level north of ,cape ,palmas1 and so form the ,guinea current4 ,the high sea-level of the equatorial calm belt of the ,atlantic contains a large portion of the conserved heat of the tropical ,atlantic1 which at this age sends off a somewhat limited supply of warm water to the ,gulf ,stream1 and also to the ,brazil current4 ,but1 whenever the ,cape ,horn channel is closed or much obstructed1 so causing a great low sea-level in the ,southern ,atlantic1 the tropical waters heaped against ,brazil1 and the raised waters of the great calm region being one continuous high sea-level1 would mostly be attracted to the vast low sea-level of the southern ocean4 ,hence it will be seen how large a portion of the conserved heat of the tropical ,atlantic would be used to warm the high southern latitudes during a warm period in the southern hemisphere1 and at the same time the head-waters of the ,gulf ,stream would obtain the same height as now4 ,for we now see much of the force of the north-east trade winds lost1 while maintaining so large a high sea-level to the windward of the ,west ,india ,islands1 which is probably capable of supplying a stream of double the capacity of the gulf current which passes through the ,florida channel4 ,and it appears1 while viewing the vast reservoirs of warm water apparently gathered by trade winds to subdue the cold of the high latitudes1 that much of the energy of such winds is now lost to the world1 while maintaining a vast and pent-up high sea-level which has a difficult outlet to the northern seas1 and no strongly attractive low sea-level to move its waters into the oceans of the high southern latitudes4 ,the wide waters which are banked up to the windward of the ,west ,india ,islands1 and cause the wide tide-rips1 set mostly to the westward into the ,caribbean ,sea through the passages south of ,guadeloupe1 while the northern portion of the raised waters set mostly toward the north1 and thus form the eastern boundary of the ,gulf ,stream1 and comprise the inner circle of the great current that encircles the ,sargasso ,sea4 ,i have been informed by an old ,barbuda fisherman that 8the weeds which float on the surface of the ,sargasso ,sea grow in large quantities on the bottom of the shoal waters to the north and eastward of that island and ,antigua40 ,consequently1 the currents of that region carry such weeds as become detached from their places of growth into the higher latitudes1 where the westerly winds in the winter season drift them eastward south of ,bermuda1 until finally the central area of their gathering1 where the most dense collection of weeds is found1 is situated near the tropic of ,cancer1 and about #ee west longitude1 as shown on map ,no4 #b4 ,this position is also the centre of the great circular currents which encompass the ,sargasso ,sea4 ,the comparatively few weeds which enter the ,gulf ,stream abreast ,florida are currented to the northward of the ,bermuda ,islands1 and from thence drifted by the westerly winds to the south-west of the ,azores before entering the trade-wind belt4 ,the weeds1 on their long drift from their native shoals1 hold their freshness1 and continue to grow while floating on the sea for a considerable time1 but at length lose their renovating properties1 and in certain areas of the sea acquire an appearance of age and decay4 ,the ,gulf ,stream1 and such other tropical waters as are attracted northward to the low sea-level abreast the ,north ,american coast1 pass into the westerly wind-belt1 and so gradually become drift currents1 while being forced by the winds over to the ,european side of the ocean1 as we have previously shown4 ,the vast movement of the ,north ,atlantic waters encircling the great ,sargasso ,sea has often been pointed out by writers on the subject4 ,but the central and most dense portion of the vast sea of weeds has always been placed on the charts several degrees of longitude east of its true position4 ,it is fifteen years since ,i wrote of the ,gulf ,stream and arctic currents as being attracted to a low sea-level caused by the westerly winds4 ,but1 as far as ,i know1 writers on the ,atlantic currents have had nothing to say of the great low sea-level caused by the westerly winds blowing the surface waters of the ,north ,atlantic away from the eastern coast of ,north ,america1 from ,georgia to ,newfoundland1 and thus attracting the arctic and ,gulf ,stream waters in opposite directions1 fifteen hundred miles along the ,north ,american coast4 ,for1 were it not for this low sea-level1 the ,gulf ,stream would not be able to move so far northward as it now flows1 but would spread out1 were there no unevenness in the sea-level of the ,atlantic1 and become a drift current far south of its present northern limits4 ,the ,united ,states government has caused surveys to be made of the ,gulf ,stream1 and the interesting discoveries thus obtained have all been laid before the public4 ,still1 such surveys cover but a portion of the whole round of the vast movement of the ,gulf ,stream water1 and do not refer to the vast high sea-level of the calm belt as being one of its feeders1 or to the wide disturbance of the surface waters of the tropical ,north ,atlantic in their conflict with the trade winds1 while being forced to the vast high sea-level of the ,caribbean ,sea and ,gulf of ,mexico1 and so giving head to the ,gulf ,stream4 ,thus from the foregoing explanations it will be seen that the ability of the prevailing winds to move the surface waters of the ocean away from the weather shores of continents over against the opposite leeward shores in the different wind-belts of the globe1 and so cause both high and low sea-levels1 is the main reason why there is an interchange of surface water between the tropical and colder zones sufficient to carry heat from the tropics to the cooler regions1 and thus largely affect the temperature of the higher latitudes4 ,the unmistakable traces of cold periods having occurred in both hemispheres have given rise to an ingenious astronomical theory to account for their origin4 ,according to this theory the ice periods in the two hemispheres were consecutive2 and it is admitted by its supporters that1 should it be shown that the frigid periods in the northern and southern hemispheres were concurrent1 the astronomical doctrine would have to be abandoned4 ,it is impossible for a person who is acquainted with the great surface currents of the several oceans to conceive how a mild period could be maintained in the northern hemisphere with a frigid period existing in the southern hemisphere4 ,a frigid period in the latter hemisphere necessitates a cold temperature for the superior oceans of the globe south of the equator4 ,with this vast area of water reduced to a chilling temperature1 it seems impossible for the inferior waters of the northern latitudes to maintain sufficient warmth to favor a mild period in the northern hemisphere1 especially with both hemispheres receiving an equal annual amount of the sun's rays4 ,the great ,humboldt current1 having its rise in the southern ocean west of ,cape ,horn1 would during a southern frigid period greatly lower the temperature of the vast equatorial stream in the ,pacific ,ocean4 ,consequently1 the ,japanese stream1 which branches off from the equatorial current into the ,north ,pacific1 would be cooled to such a degree that it would be unable to maintain the mild climate on the shores of the ,north ,pacific which extensive lands now enjoy4 ,furthermore1 during a cold period in the southern hemisphere the temperature of the ,gulf ,stream would also be greatly lowered by the great ,south-eastern ,atlantic return current1 which is caused by the south-east trade winds impelling the surface waters of that region into the equatorial latitudes1 such waters being replenished from the common level of the southern ocean1 and so mingling the cool waters of that sea with the equatorial waters of the ,atlantic during a frigid period in the southern latitudes4 ,and it may be said that during such times the frigid ,antarctic ,ocean would send its cold under-currents to cool the inferior northern oceans4 ,even to-day the northern and southern hemispheres1 through the intermingling of the waters of the northern and southern oceans1 largely maintain a like temperature in their temperate zones4 ,therefore1 when we consider the certain traces of ice-sheets having formed on ,south ,africa and ,southern ,australia1 and to have overrun ,south ,america above the latitude of #dj south1 thus strewing the oceans of the southern temperate zone with ice that are now largely free from it1 it seems that the maintenance of warm oceans in the northern hemisphere during the time of a frigid period in the southern hemisphere would be impossible4 ,in order to make this statement more plain1 ,i will again refer to the importance of the great ,humboldt current for cooling the waters of the ,north ,pacific during the perfection of a southern ice age4 ,for during such times the ocean strewed with ice west of ,cape ,horn1 where the ,humboldt current takes its rise1 would impart its coldness to the ,humboldt stream1 while it was floating icebergs toward the equator4 ,the equatorial current of the ,pacific being a continuation of the ,humboldt stream1 its waters would partake of its coldness4 ,the ,japanese current1 being a large offshoot from the equatorial stream1 would also possess a lower temperature than it obtains at this age4 ,yet at this date1 with the southern ice-sheets confined to the antarctic lands1 it does not possess heat sufficient to prevent glaciers from flowing down to the tide-water from mountains in ,alaska4 ,consequently1 the ,japanese stream could not maintain a mild climate on the ,north ,pacific coasts while a cold period was being completed in the southern hemispheres4 ,therefore1 under the conditions above set forth the support of a mild period in the northern hemisphere during the existence of a frigid period in the southern hemisphere could not be carried out4 ,from what has been explained1 it will be seen that the growth of an ice period is necessarily slow1 especially in its early stage1 and also that the storage of ice is carried on in both hemispheres at the same time2 but ,i will call further attention to the southern hemisphere1 because it possesses greater resources than the northern for the production of an ice age4 ,the independent circulation of the southern ocean waters1 as before shown1 turns away the tropical currents1 and thus largely prevents their warm waters from entering the high southern latitudes4 ,consequently1 the heat from the sun's rays1 and all other sources of heat included1 are not sufficient to prevent ice from gathering on lands within the antarctic circle4 ,this increasing storage of ice is only another name for the accumulation and spreading of cold1 and so the increasing chillness goes on4 ,the snow falls1 and thus adds to the extension and thickness of the ice-sheets2 and at the same time the spreading snow-fields reflect the heat received from the sun's rays into space1 while the cold is retained and increased in the growing glaciers4 ,the spreading ice-sheets having covered the land are able to flow into the surrounding seas1 where their outer edges become detached and form icebergs1 which float out to sea1 and so scatter over the adjoining oceans4 ,thus their coldness is mingled with and largely preserved by the sea1 while the surface water1 which is carried into the southern latitudes from the northern oceans by the prevailing winds1 and also such surface waters as are attracted into the antarctic seas because of the difference of temperature of the antarctic waters and the more northern seas1 are on gaining the frigid latitudes made cool1 and returned to the more northern seas in cold under-currents1 and so chilling the vast under-waters of the great oceans of the globe1 and eventually their wide surface waters also2 and so the coldness increases until the ice-sheets which at first formed on polar lands are enabled to spread slowly toward the equatorial regions so long as the independent circulation of the southern ocean is maintained4 ,but at length the depth of the great southern ocean is diminished because of the water evaporated from its surface1 and precipitated in the shape of hail and snow over the vast continents and islands of the high northern latitudes1 thus adding sufficient weight to the northern lands to attract the waters of the southern seas and still further lessen their depth4 ,thus during such times the ,cape ,horn channel is so reduced as to be obstructed by the heavy glaciers and icebergs of an ice age4 ,consequently1 a great change is wrought in the circulation of the southern seas4 ,for1 when the ,cape ,horn channel is closed1 the westerly winds employ their strength to force the ocean's surface waters away from the glaciers which have filled the diminished channel4 ,this potent action of the winds necessarily creates a great low sea-level on the ,atlantic side of the obstructed strait1 sufficient to attract the tropical waters heaped against ,brazil by the trade winds1 and the waters of the high sea-level of the equatorial calm belt1 and also the equatorial waters which set along the east coast of ,africa1 well into the southern seas4 ,it will thus be seen that the conditions for the circulation of the tropical ocean waters have met with a great change4 ,but the temperature of the waters has been lowered by the coldness of a frigid period2 and1 consequently1 their capability for conveying heat to the high latitudes has largely diminished4 ,therefore1 their first inroads in the higher latitudes make small impression on the icy seas1 so the early process for melting ice is exceedingly slow4 ,but the icy southern ocean1 deprived of its independent circulation1 in the course of time yields to the warming invasion of the tropical waters1 whose wide and increasing spread is eventually able to bring about a mild period1 according to the natural methods which ,i have explained in the preceding pages4 ,and it may be said that a mild period succeeding a glacial age gained sufficient warmth to melt the ice-sheets from all lands excepting the highest mountains4 ,for it is probable that there are lands situated in the antarctic circle sufficiently elevated even during late ,tertiary times to have been above the snow-line4 ,therefore1 the glaciers on such lands could not have melted away during mild periods succeeding an ice age4 ,for1 as has been explained1 a portion of the waters of the southern seas had moved into the northern hemisphere4 ,consequently1 the antarctic lands were raised higher above the sea-level than at this age4 ,hence the area of lofty land was increased above the snow-line4 ,and1 according to ,dr4 ,james ,croll's estimate1 the ice-sheet at the south pole is at this age several miles in thickness4 ,therefore1 its upper surface is above the line of perpetual snow1 and could not be melted away during the warm eras succeeding glacial periods4 ,,chapter ,,iii4 ,,the ,,spread ,,of ,,glaciers ,,during ,,cold ,,epochs4 ,i have before explained that the conditions are such that the cold periods of the northern and southern hemispheres were concurrent4 ,through this cause1 while the glacial epoch was being perfected1 the ice followed down the mountain ranges of both hemispheres2 and1 while gathering on the lands of the temperate latitudes1 it also spread over a portion of the tropical zone4 ,it is reported that traces of ancient glaciers are found in ,india1 and also in ,central ,america and in tropical ,south ,america4 ,in fact1 the denudation caused by ancient glaciers on the elevated lands of the tropics are too well defined to be attributed to any process of weathering1 while ,alpine plants of the same species are found near the summits of mountains in the tropics as well as in the high latitudes of both hemispheres4 ,this fact goes to show that a portion of the lowlands of the tropical zone have experienced a temperature favorable for the growth of ,alpine plants4 ,and1 judging from the tropical islands ,i have visited1 situated in the cold currents which flow down the eastern sides of the oceans from the high latitudes1 ,i think they show strong traces of having during some remote period been subject to the action of glaciers4 ,the island of ,st4 ,helena1 situated in the southern tropical ,atlantic1 has the appearance of having been heavily iced during a frigid age4 ,its steep ravines1 which deepen as they approach the sea1 recall to the southern voyager the ice-worn islands of the high latitudes4 ,it seems improbable that these deep ravines which penetrate the hard volcanic rock1 on their short course to the sea1 could have been caused by their scanty brooklets4 ,the bowlders scattered over the island are not in harmony with the weathering process1 while the obliteration of its craters seems to point to a more rapid process of erosion than could be attributed to weathering4 ,professor ,agassiz1 in his 8,general ,sketch of the ,expedition of the #8,albatross1'0 states that the ,galapagos ,islands are of volcanic origin1 and that their age does not reach beyond the earliest ,tertiary period2 and his report seems to favor the impression of their having undergone denudation sufficient to slough off large portions of the rims of the older craters1 and also the eastern face of ,wenman ,island4 ,on ,hood's ,island1 at the time of my visit1 its crater had entirely disappeared4 ,the highest portion of the island1 which was the probable site of its ancient crater1 showed no trace of its former existence2 yet at the foot of this low mountain1 on its southern side1 ,i saw a large collection of loose bowlders1 composed of hard volcanic rock1 which were mostly free from soil and other dbris1 and easily moved from their places1 while the spaces afforded by the loose piles of dark basaltic rocks afforded a secure retreat for numerous owls and lizards4 ,beyond the rocky piles to the southward a horizontal area of land was strewn with bowlders to the sea1 which was some two miles distant from the higher land4 ,the bowlders which covered the plain were somewhat smaller than those at the foot of the mountain1 as none of the former were more than three or four feet in their longest measurement4 ,they seem to have been formed from thin strata of lava1 which were broken in pieces from pressure1 such as the action of ice could perform4 ,in fact1 the crowded and angular and somewhat worn blocks of lava presented a different appearance from stones thrown from the crater of a volcano1 while no such bowlders are found among the recent volcanic eruptions on the islands4 ,the plain so thickly strewn with bowlders1 and partly shaded by a tall growth of shrubs1 fell off abruptly at the seaside1 forming a steep cliff some two hundred feet in height4 ,the rocky floor at the foot of the cliff received such dbris as fell from the sea-washed land2 yet it contained few bowlders1 they having been washed away by the waves soon after falling4 ,at one place a steep1 dry ravine penetrated the land from the seashore1 which was dangerous to cross on account of the loose stones resting on its sides4 ,two or three miles further west1 on the level land bordering the sea1 a large rookery of albatross were brooding their eggs and chicklings4 ,the land on the south side of ,albemarle1 near the sea1 consists of dbris from the eroded high lands2 and1 judging from the crumbling cliffs by the sea1 it seems that the land at one time extended further seaward4 ,besides the excessive denudation which appears to have taken place on portions of these bowlder-strewn lands1 we have other unmistakable testimony of their having formerly possessed a frigid temperature4 ,the characteristic ,alpine flora of these islands points to a time when they were exposed to a cold climate4 ,furthermore1 rookeries of seal and albatross1 which naturally belong to shores situated in cold latitudes1 still exist on these equatorial islands2 and1 when we consider the favorable position of the ,galapagos for the reception of cold during a frigid period1 we can well account for the lingering signs which point to their former cold climate4 ,during the perfection of an ice period the western shore of ,south ,america was covered with an ice-sheet from the summits of its mountain range to the sea1 extending northward as far as the latitude of #ch south4 ,this vast ice-sheet1 situated in a region of great snow-fall1 was constantly sending icebergs into the sea1 where they were borne northward by the cold ,humboldt current directly toward the ,galapagos ,islands2 while1 on the other hand1 in the northern latitudes1 in regions of great snow-fall1 such as ,alaska and ,british ,america1 numerous icebergs were launched into the ocean1 to be currented southward to the ,galapagos seas4 ,thus during the frigid epoch the equatorial waters surrounding the ,galapagos group was one of the greatest gathering places for floating ice to be found on the globe4 ,and here the frigidity stored up in the glaciers of the higher latitudes was set free1 thus chilling the waters as well as the atmosphere of that region4 ,the ,alpine flora of the ,american coast mountains was probably carried by floating ice to the ,galapagos1 while its rookeries of albatross and seal date back to a cold period4 ,and it seems that these cold-weather animals1 with the assistance of the cool ,humboldt current1 may be able to preserve their rookeries at the equator until the advent of another ice period4 ,in connection with the evidences of a cold climate having possessed the ,galapagos1 there are ample traces of ice-sheets having flowed over a large portion of the high lands of tropical ,america1 and in some places the ice may have flowed down to the sea1 especially where the large rivers now empty2 and it is said that masses of clay1 mixed with sub-angular stones1 have been found in ,brazil1 which goes to prove the glaciation of portions of that tropical land during a remote age4 ,professor ,louis ,j4 ,r4 ,agassiz1 during his research in the ,amazon valley1 found bowlders resting near the summits of the low hills of that region1 which he attributed to the action of ice4 ,the spread of glaciers on southern continents and islands is shown on map ,no4 #a4 ,in ,science1 ,nov4 #ag1 #ahic1 ,mr4 ,j4 ,crawford published a summary of his discoveries in ,nicaragua1 during ten months of nearly continuous exploration since ,august1 #ahib4 ,the author of this report says3 8,the numerous eroded mountain ridges and lateral terminal moraines of that tropical region give unquestionable evidences of the former existence of a glacial epoch1 which covered an area of several thousand square miles in ,nicaragua with glacial ice4 ,the ice-sheet covered a large part of the existing narrow divide of land 7containing about #dh1jjj square miles7 between the ,pacific and ,caribbean ,sea40 ,and it is likely that other large areas of tropical ,america were glaciated at the same time1 especially in regions of great precipitation4 ,the island of ,cuba1 during a portion of the ice age1 probably supported heavy glaciers1 and obtained an average temperature as low as ,south-western ,new ,zealand at this age4 ,according to the description given by ,j4 ,w4 ,spencer1 of the ,cuban land1 great valleys have been excavated1 the lower portion of which are now fiords1 reaching in one case at least to seven thousand feet in depth before gaining the sea beyond4 ,thus1 while keeping in view the glacial condition of ,central ,america during the frigid period1 it seems that the great ,cuban excavations were partly the work of glaciers of the same cold epoch499 ,judging from such reliable statements1 it is probable that the climate of tropical ,america during the frigid age was somewhat colder than obtained in the tropical regions of the eastern continent1 owing to the wide connection of the ,atlantic with the ,arctic ,ocean as well as with the antarctic seas1 and because of its shores possessing a larger area of glaciated lands in proportion to its size than the ,pacific and ,indian ,oceans1 and also owing to the tropical ,atlantic containing so small a portion of the world's waters which lie within the torrid zone1 and its equatorial current being separated by continental lands from the great equatorial stream of the ,pacific and ,indian ,oceans4 99,the meeting of the ,british ,association for the ,advancement of ,science1 ,september1 #ahie1 was reported in ,science of ,october #ah1 where mention is made of an interesting paper by ,mr4 ,r4 ,b4 ,white1 on 8,the ,glacial ,age of ,tropical ,america10 in which he described a number of apparently glacial deposits in the ,republic of ,colombia1 almost under the equator4 ,he spoke of moraines forming veritable mountains1 immense thicknesses of bowlder clay1 breccias1 cement beds1 sand1 gravels1 and clays1 beds of loess1 valleys scooped1 grooved1 and terraced1 monstrous erratics1 and traces of great avalanches4 ,therefore1 the tropical ,atlantic waters must have been reduced to a lower temperature during a frigid age than the tropical waters of the ,indian ,ocean or the western part of the tropical ,pacific1 as a large portion of the great equatorial current of the latter oceans1 during its western movement1 was exposed to the rays of a tropical sun for a much longer time1 after being replenished by the cold waters of the high latitudes1 than the tropical currents of the ,atlantic2 and it is probable that1 on account of tropical ,america possessing a colder climate than the tropical lands of the eastern continent during the frigid epoch1 the cold of the western continent was more destructive to its fauna and flora than was the case in the tropical regions of the eastern continent4 ,professor ,wright1 in his valuable work on 8,the ,ice ,age of ,north ,america10 gives a good description of the 8flight of plants and animals during the glacial epoch10 and also of the extermination of many superior species because of the frigid climate4 ,the high lands of tropical ,africa1 above the altitude of three thousand feet1 and situated in places of great precipitation1 were probably covered with snow and ice during the glacial age4 ,travellers have reported that islands composed partly of granite bowlders are found in the lakes at the head-waters of the ,nile4 ,but the glaciers that invaded the tropical latitudes were of short duration compared with the ice-sheets that burdened the lands of the temperate zones4 ,besides1 such tropical ice as flowed to the low lands was so near a melting condition that it made small impression on the rocks2 but on steep mountain slopes1 where the movement of the ice was comparatively rapid1 it possessed considerable eroding power4 ,the climate of the tropical zone on both continents during the perfection of an ice period was so cold that such animals as could not endure a low temperature retreated into the warmest regions of the equatorial latitudes1 while many species who failed to reach such places perished4 ,and especially was this the case with the pre-glacial fauna of the western continent4 ,mr4 ,w4 ,b4 ,m4 ,davidson1 in his treatise on ,florida phosphates1 says3 8,the great mammal hordes of the glacial epoch were driven into ,florida in their flight southward for life and warmth1 and there perished because of the deadly cold which ever moved southward4 ,the ,florida waters grew so icy cold1 fishes1 reptiles1 and mammoth animals died1 and added their frames and teeth to the valley of bones now found in that southern region40 ,such species of the tropical fauna of the ocean as survived the ice age could have existed only in torrid seas with small connection with the cold oceans during the frigid epochs4 ,for1 with the diminished oceans of a cold period1 it seems that the conditions were favorable for the maintenance of such seas in the region of the ,east ,india ,islands4 ,such parts of ,southern ,europe and ,northern ,africa as bordered on the ,mediterranean ,sea probably possessed a milder climate during the ice age than regions in the same latitudes on the ,atlantic coast1 for the reason that the ,north ,atlantic was proportionally a greater receptacle for icebergs which were launched into it from the numerous glaciers of ,north-eastern ,america1 ,greenland1 ,iceland1 and ,north-western ,europe than the great inland sea obtained from its less frigid shores4 ,and it may have happened that during such times the tropical waters of the ,indian ,ocean had some connection with the ,mediterranean through the ,red ,sea and ,suez1 and so during portions of the year the waters of the tropical ,indian ,ocean were forced by the periodical winds into the inland sea4 ,it is the opinion of several writers that man1 along with other species of animal life1 existed previous to the glacial period2 for1 since the seas and lands of the globe were chilled1 the conditions seem to have been less favorable for the spontaneous generation of animate bodies than during the previous warm ages4 ,therefore1 it appears that the generative ages should be ascribed to the long genial eras prior to the glacial epochs4 ,for it is probable that the lower parts of the ocean1 which now possess a low temperature even in the tropical latitudes1 were1 during the warm eras1 wholly composed of warm water1 because the surface waters of the antarctic seas of that age1 which supply the great under-currents of the ocean1 would possess a high temperature2 and it is probable that the temperature of a large portion of the seas of the torrid zone was for a long time maintained at blood heat4 ,for it should be considered that the waters which moved from the torrid seas1 after making their journey through the warm regions of the high latitudes1 would on their return to the tropics retain a large portion of the heat they acquired in the torrid zone before making their journey to the mild polar regions4 ,and1 when we reflect how the heat of the sun's rays was conserved by the ocean waters1 and that their circulation during such times was almost wholly performed by the winds1 as the difference of temperature between the polar latitudes and the equator was small1 it appears that during the eras previous to the glacial age the oceans must have obtained a higher temperature than possessed by the warmest seas of to-day4 ,according to the discoveries of ,professor ,wright and others1 ancient stone implements have been found beneath the glacial drift1 as well as the bones of animals whose descendants are now living1 which goes to prove that man1 with other species of fauna which now inhabit the earth1 existed anterior to the glacial epoch4 ,and on consideration it seems unreasonable to suppose that any of the superior species of animals could have been brought into existence since the waters and lands of the earth were chilled by the cold of a glacial age4 ,and it appears that many species of animals which are known to have survived the cold periods were indebted for such survivals to the slow process through which a frigid period is brought about1 thus affording time for evolutionary inurement to the slow increase of cold which at length perfects a glacial epoch4 ,the inurement to cold acquired by animals during the glacial age is still an attribute possessed by many species of fauna to-day4 ,for1 when a warm climate took possession of the tropical zone1 it was deserted by a large portion of the animals that found refuge there during the glacial age4 ,thus1 while the seas and shores of the cooler latitudes swarm with animate bodies1 the torrid latitudes seem comparatively lonely to the voyagers on the tropical oceans4 ,,chapter ,,iv4 ,,the ,,glaciers ,,of ,,the ,,temperate ,,zones4 ,having asserted that during the culmination of a frigid period the ice-sheets spread over a portion of the lands of the tropical zone1 ,i will give my views1 with those of several writers1 on the spread of ice-sheets within the now temperate latitudes2 and meanwhile ,i will repeat a portion of my former essays on the subject4 ,professor ,hitchcock1 in his lectures on the early history of ,north ,america1 says that 8the history opens with igneous agency in the ascendant1 aqueous and organic forces become conspicuous later on1 and ice has put on the finishing touches to the terrestrial contours40 ,but there appear to be various opinions held by geologists respecting the changes brought about on the earth's surface during the glacial period4 ,some think that glaciers have never been an important geological agent1 while others assert that during the glacial epoch heavy ice-sheets covered the elevated portions of ,western ,north ,america as far south as the thirty-sixth parallel of latitude1 and ,eastern ,north ,america was overspread with ice-sheets1 which attained a depth of five or six thousand feet1 and were able to move their dbris over wide lands of little declivity toward the sea1 their immense deposits forming the lands of ,cape ,cod1 and also the islands of ,nantucket and ,martha's ,vineyard4 ,but it is now said that this implied magnitude of the glacial deposits on the lands skirting the ,new ,england coast is without foundation1 since the larger bulk of these islands consists of upturned ,cretaceous and ,tertiary strata1 which are only thinly covered with glacial dbris1 such as bowlders1 gravel1 clay1 and sand1 from the eroded shores of the mainland of ,new ,england4 ,but it appears that the dislocated and folded cretaceous strata which underlie the glacial drift of ,nantucket and ,martha's ,vineyard were during an early period deposited on the bottom of a shallow sea1 which then covered the ,vineyard ,sound1 ,buzzard's ,bay1 and their surrounding lowlands4 ,thus the ice-sheets of the frigid age which moved over ,new ,england displaced the yielding stratified deposits of the shallow sea1 and forced them southward in a disturbed condition to the position which they now occupy4 ,still1 it is apparent that only a small portion of the glacial drift is found on these islands1 which1 according to appearances1 must have been eroded and moved southward from the rocky lands of ,new ,england during the ice age2 but there is sufficient to show that large quantities of such dbris were carried over the islands into the ,atlantic4 ,and1 judging from the eroded rocky ,new ,england lands1 there must have been sufficient glacial drift moved over ,nantucket and ,martha's ,vineyard into the ocean beyond to far exceed in bulk the deranged ,tertiary and ,cretaceous deposits which now form so large a portion of the islands4 ,for1 when we look over lands bearing traces of the ice age1 where the glaciers did not move their drift into the sea1 so the terminal moraines of such glaciers can be better estimated1 we can realize the great work that has been performed by the ice-sheet that overran ,new ,england during a frigid age4 ,professor ,james ,geikie states1 in his discussion on the glacial deposits of ,northern ,italy1 that the deposits from ,alpine glaciers of a frigid period 8rise out of the plains of ,piedmont as steep hills to a height of fifteen hundred feet1 and in one place to nearly two thousand feet4 ,measured along its outer circumference1 this great morainic mass is found to have a frontage of fifty miles1 while the plain which it encloses extends some fifteen miles from ,andrate southward40 ,and it is reported that there are found on the southern flank of the ,jura numerous scattered bowlders1 all of which have been carried from the ,alps across the intervening plains1 and left where they now rest4 ,many contain thousands of cubic feet1 and not a few are quite as large as cottages4 ,such blocks are found on the ,jura1 at a height of no less than two thousand feet above the ,lake of ,neuchtel4 ,the ,jura ,mountains being formed of limestone1 it is easy to distinguish the dbris deposited by ,alpine glaciers2 and1 from what ,i can learn of extensive glacial work1 it appears that intervening plains1 lakes1 and sounds are so often found separating the source of ancient glaciers from their deposits that their existence becomes almost necessary to represent the general outlines of disturbance performed during an ice period4 ,in consideration of such facts and the foregoing statements of reliable observers1 ,i am prompted to offer my views on glacial work performed on a portion of the ,pacific shores of ,north ,america1 which seems to me to be much more extensive than hitherto supposed4 ,professor ,whitney describes the coast mountains of ,california as being made up of great disturbances1 which have been brought about within geologically recent times2 and this statement ,i found to be so obvious in my travels over that region that it appears to me that the coast ranges originated in a different manner from the older ,sierras4 ,the western sides of the latter mountains everywhere show the great eroding power of ancient glaciers2 and1 when ,i considered their favorable position for the accumulation of snow during a glacial period1 ,i was led to seek for the glacial deposits adequate to represent the great gathering of ice which an age of frigid temperature would produce4 ,but it seemed to me that such deposits could not be found in the foot-hills of the ,sierras1 which contain the moraine of inferior ice-sheets that terminated at the base of the mountains4 ,under these conditions ,i came to the conclusion that during the earlier ice period the immense glaciers which must have formed on the western slopes of the ,sierra range moved their gigantic accumulation of dbris so far seaward as to form the range of hills now existing next the coast line1 and perhaps the islands abreast the ,santa ,barbara coast1 the ,contra ,costa1 or eastern range1 being formed during a subsequent ice period1 in the same manner as the hills next the coast line4 ,still1 it may be that neither of the coast ranges was the work of a single cold epoch2 but the western range must necessarily have been the earliest deposit4 ,although the coast ranges differ from the ,sierras in their make up1 yet it does not disagree with the glacial origin of the former inferior mountains1 from the fact that the ice-sheets1 while moving their bulk westward1 displaced the deposits of such bays1 lakes1 rivers1 and marshes as lay abreast of the ,sierra slopes4 ,the advancing ice-sheets1 thousands of feet in depth1 moving from a lofty and steep incline1 pressed and ploughed below the somewhat superficial cretaceous and alluvial strata which lay in their course4 ,the disturbed strata1 while forced along in confused heaps in front of the ice1 were amassed in ridges sufficient to form the hills of the coast ranges4 ,the bowlders found imbedded in several of the coast hills must have been moved by the ice from the ,sierras on account of the coast ranges not having a rocky core of sufficient firmness to give shape to such bowlders4 ,moreover1 the temperature of the ,pacific waters would not be favorable for glaciers to form on the coast ranges1 with the ice-sheets of the ,sierras terminating at the foot-hills4 ,the ,sacramento and ,san ,joaquin ,valleys are now covered by recent river deposits4 ,therefore1 the glacial drift which should be traced from the ,sierras to the coast ranges is concealed4 ,yet the abraded appearance of exposed solid rocks at the base of the foot-hills1 and also the scattered bowlders which gradually disappear beneath the diluvial deposits of the plains1 indicate that the ,sierra ice-sheets could not have ended at the foot-hills1 but must have moved further westward1 while gathering immense accumulations in their front1 sufficient to form the coast hills1 the dbris thus amassed being able to arrest the further movement of the ice seaward4 ,the coast ranges in several places have been subject to igneous action1 which may have been brought about through heat generated from pressure exerted on the interior masses after the ice had melted away1 the heat thus produced being sufficient to cause outbursts of lava1 where the nature of the material favored combustion4 ,the low plains1 lakes1 and bays which separate the ,sierras from the coast hills are in a position similar to the shallow sounds which separate ,nantucket1 ,martha's ,vineyard1 and ,long ,island from the inferior slopes of the mountains of ,new ,england4 ,therefore1 while agreeing with glacialists1 who believe that great geological changes have been wrought by ice-sheets in ,italy and ,new ,england1 it appears to me that the ancient glaciers of the ,sierra ,nevada have accomplished more extensive work1 owing to the ,sierras being situated in a more favorable position to receive the humidity of the ocean4 ,hence1 with a low temperature1 vast quantities of snow must have collected on their lofty sides2 and at the same time their great height and declivity would cause the ice to move down their steeps with greater force than the glaciers which passed over ,new ,england4 ,writers who have given the subject considerable study think that the deep valleys of the ,sierra ,nevada were produced by disruptive rather than erosive agencies4 ,this conclusion has been formed from the lack of large accumulations of dbris about their lower extremities1 which would not be the case if such valleys were the result of glacial erosion4 ,but1 should the coast ranges be attributed to glacial action1 as has been stated1 we can well account for the dbris that should accumulate from the erosion of the deep valleys4 ,the only thing that could prevent the ice from gathering on the ,sierra ,nevada range during an ice period in greater masses than on any mountains in the northern hemisphere would be the lack of cold2 for1 with a low temperature1 the fall of snow would be enormous4 ,this is shown by the great snow-fall during the short mild winters of to-day4 ,therefore1 with ice-sheets covering a large portion of the lands of the high northern latitudes1 and with the ,japanese current which tempers the north ,pacific waters made cold in the manner described in the foregoing pages1 and while the sea along the north-west coast of ,america was strewn with icebergs launched from ,alaska and ,british ,columbia1 it seems that ,california must also have obtained a frigid climate during the ice age4 ,therefore1 on account of its exposure to the ocean winds1 and the consequent heavy snow-fall1 the accumulation of ice on its lands must have been immense4 ,for1 when it is considered that the glaciers of ,north ,america extended southward even into the torrid zone sufficient to cover a large portion of ,central ,america1 it is unreasonable to suppose that any portion of ,california could escape being covered by heavy ice-sheets during the glacial epoch4 ,the comparatively scant fall of rain and snow over ,greenland is known to form ice-sheets hundreds of feet in thickness4 ,therefore1 what must have been the depth of ice over the high lands of the ,pacific coast north of ,california at the culmination of a frigid period8 ,the descriptions given by ,dr4 ,dawson and others1 of glacial phenomena along that coast1 favor the impression that an immense ice-sheet at one time deeply covered the whole region from the top of the mountain range to the ocean4 ,thus all the deep channels were filled and all the islands deeply overrun with ice1 while the immense bergs launched from the shore and carried by the winds and currents southward were probably not melted until they reached the tropical latitudes4 ,thus1 when the whole circulation of the ,pacific waters are taken into account1 it will be seen that their temperature during the ice age must have been considerably lowered4 ,the movement of ice-sheets on the ,pacific slope was probably local in character1 and not connected with the movement of ice on the eastern sides of the mountains4 ,from what ,i have seen of the vast territory lying between the ,sierra ,nevada and the ,rocky ,mountains it appears that it obtained much heavier ice-fields than generally supposed4 ,professor ,geikie in his lectures says of this region that during the glacial age1 8in the ,second ,colorado ,canyon1 the sides were completely glaciated from bottom to top4 ,these walls are from #hjj to #a1jjj feet high1 and at the thickest point the glacier was #a1gjj feet thick02 and he says that 8the country around ,salt ,lake was covered with ice1 for the rocks about there show the action of ice1 and that the bones of the musk-ox are found there40 ,this vast area of ancient ice1 although subject to little movement in its interior basin1 still1 in whatever movement it may have had1 must have found its main outlet through the ,grand ,canyon of the ,colorado4 ,for in no other way can we account for the erosive forces necessary to excavate that immense chasm4 ,not even the mighty torrent that carried off the waters of the melting ice-sheets that covered the interior portion of the continent could accomplish work of such magnitude4 ,according to ,professor ,geikie's observations the ,second ,colorado ,canyon was filled with glaciers during the ice age4 ,therefore1 it seems that these glaciers must have flowed down into the ,grand ,canyon1 and there united with glaciers flowing from more northern regions4 ,an account of a collecting expedition to ,lower ,california by ,g4 ,eison1 in #ahie1 describes ancient moraines at the extremity of the peninsula as being prominent1 large1 and steep4 ,this region lies under the tropic of ,cancer1 and #h south of the mouth of the ,colorado ,river where it empties into the ,gulf of ,california4 ,hence it appears that the temperature of that portion of ,north ,america during the ice age was favorable for the great glacier of the ,colorado ,canyon to have flowed into the ,gulf of ,california4 ,the wide1 shallow basins of ,utah and ,nevada were filled with the water from the melting ice-sheet on the breaking up of the ice period1 and the lakes so caused remained for a considerable time after the disappearance of the ice4 ,but1 owing to the great evaporation and light rain-fall of that region1 the lakes gradually shrank away1 the filling and emptying of the lake basins being governed by the cold and mild epochs4 ,the conglomerate deposits in the ,appalachian district of ,north ,america are known as occurring on a large scale4 ,professor ,shaler is inclined to attribute them to glacial action1 because he knows of no other force that could bring together such masses of pebbles from a wide-spread surface4 ,in ,eastern ,kentucky and ,east ,tennessee these deposits are found to be several hundred feet in thickness4 ,such accumulations of apparent glacial origin are to be found from ,new ,brunswick to ,alabama4 ,hence it seems that the ice during a frigid period followed down the ,alleghany range even so far south as ,georgia and ,alabama2 and for a time1 when the ice attained its greatest spread1 it flowed over the central portion of the ,gulf ,states4 ,for how else can we account for the clay mixed with gravel and pebbles and stony fragments being spread broadcast over that region8 ,i know that such statements do not agree with the views of glacialists who have written on the subject1 and have drawn the glacial boundary from seven to ten degrees further north1 where a line of bowlders with other glacial dbris is plainly traced4 ,still1 it appears to me that a line of bowlders deposited by an ice-sheet spreading over a continent and across many degrees of latitude cannot be compared to the moraines of inferior mountain glaciers of the temperate latitudes of the present age4 ,an ice-sheet moving from a high latitude to a lower would1 while in the colder latitude1 freeze firmly to the rocky ledges1 and hold them so strong in its frigid grasp as to break off the weaker portions of the rocks1 and drag them toward a milder region1 as far as the freezing grip of the ice-sheet would permit2 but1 on gaining lower and milder latitudes1 the holding and dragging power of the ice would be lost on account of the increased warmth of the earth over which the glacier must pass1 and also because of the ice-sheet having lost a portion of the low temperature acquired in the higher latitudes4 ,therefore1 on such lines the bowlders would be released1 while the ice-sheet would still move on1 although largely deprived of its eroding power4 ,this is the probable reason why a line of glacial dbris1 largely composed of bowlders1 is found to extend across the ,middle and ,western ,states1 and so generally supposed to be the glacial boundary of a frigid period4 ,but there is no reason to suppose that an ice-sheet1 although deprived of its eroding power1 was arrested in its southern movement on the line of its stony dbris1 because there could be no sudden change of temperature in a particular latitude on the eastern lands of ,north ,america to cause an abrupt ending of the ice-sheets4 ,and there appears to be nothing to hinder the ice from gathering and flowing over lands warm enough to loosen its implements of erosion2 for there is much to show that the ice-sheets flowed much further southward1 even into the middle portion of the ,gulf ,states1 and there spread the clay mixed with gravel and pebbles1 with now and then a bowlder1 over the land4 ,the scattered bowlders1 found in numerous instances many miles south of the bowlder line1 were so deeply imbedded in the ice-sheet that they could not be dropped on the usual releasing ground4 ,the ice-sheet1 when deprived of its rocky1 eroding implements1 would1 while flowing over the land1 leave few or no imprints on the rocks2 but it would probably move and spread a large amount of clay1 gravel1 pebbles1 and sand over its wide course1 especially if the ice moved from a region abounding with such material4 ,should we place the glacial boundary on the line of the rocky dbris1 how could we account for the glaciated stones found on the hills and plains situated far southward of the bowlder-strewn regions of the ,middle and ,western ,states8 ,the clay mixed with gravel and sand1 and spread so broadcast over a large portion of ,georgia and even into ,northern ,florida1 makes it appear that the ice of a cold period must have covered that southern region4 ,moreover1 it seems to have been through the great abrasion which only ice-sheets could perform that the sands of the ,florida peninsula were produced2 for on examination they seem to have resulted from the abrasion and weathering of crystalline rocks4 ,the worn remnants of such rocks are now found in the southern ,appalachian range4 ,in fact1 the hills and mountains of that region at the present time are supposed to be a small remnant of the ancient highlands4 ,thus1 on consideration1 it appears that the sands caused by the action of glaciers were1 on the disappearance of ice-sheets1 blown by the strong north-west winds toward the ,florida peninsula as fast as the receding waters of the ocean which flowed the lowlands on the breaking up of the ice age would permit2 and in this way the sand was spread over the lowland region1 which was largely composed of coral sea shells and other marine matter4 ,and it seems that the sand must have been blown over large areas in ,florida soon after the ending of the frigid period1 because the sand1 in order to be moved by the winds1 must have spread over a country nearly destitute of vegetation2 and such would be the condition of that region during times which succeeded the ice period and the subsequent brief flowage of the lowlands on the ending of the frigid age1 which would not be the case if such sands resulted entirely from water erosion and weathering1 because with such a state of things the country would be covered with forests and grasses1 which would prevent the sand from being moved by the winds to any great extent4 ,this goes to show that the region of the ,gulf ,states was so much affected by the cold of the glacial period1 together with the submergence of the lowlands at its close1 its flora and also its animals were exterminated2 for how else can we account for the abundant fossil remains of animals now found buried in the ,florida sands8 ,it appears also that1 when ,florida was being covered with drifting sands1 many of the lake basins now formed did not exist1 as the wind-blown sand could not have crossed a continuous chain of lakes like the ,st4 ,john's ,river2 and it is an easy matter to-day to trace the beds of the ancient lakes that prevented the sands from drifting over certain lands now nearly destitute of it4 ,and it is probable that the sea flowed the lowest lands during the period when the winds were drifting the greater portion of the sands over the peninsula4 ,therefore1 regions which embrace the ,everglades and portions of the ,indian ,river territory are quite free from heavy sand deposits1 and so also are the extensive flat woods of the peninsula4 ,since the sands blew over the ancient desert of ,florida1 many lake basins have been formed because of the sinking of the ground4 ,this sinking of the ground is a common occurrence in limestone regions1 where a great amount of material is moved in solution1 leaving caverns whose roofs often fall in4 ,the great amount of sand blown upon ,florida caused the marine strata to give way in the weaker places under its burden4 ,the sinks thus formed1 probably of frequent occurrence at one time1 have now nearly ceased4 ,still1 there are depressions to be seen to-day where the tops of large pine-trees1 which grew on dry1 sandy land1 are barely above the surface of the water which partly fills the basins so recently formed4 ,yet ,i would not assert that all of the depressions where ,florida lakes exist were caused by the sinking of the ground2 for the winds may have caused shallow basins in the sand1 where the decayed vegetation has formed mud sufficient to hold the water which now partly fills such basins4 ,the mobility of ,florida sands can be seen to good advantage when exposed to a strong1 dry north-west wind1 where the ground happens to be destitute of vegetation4 ,an observer can then realize what the result would be1 should the whole land be deprived of vegetation and laid bare to the action of the winds4 ,under such conditions1 not only would the winds be much stronger than now1 but the air near the ground would be filled with sand1 moving like drifting snow in a ,dakota blizzard4 ,and1 furthermore1 it is probable that the rainfall was very light while ,florida was void of vegetation2 and1 even if shallow basins were formed1 there would be a lack of rain to supply them with water4 ,the wide plains west of the ,mississippi ,river1 extending southward into ,texas1 during the frigid period must have been covered with a sheet of ice and snow4 ,and it is probable that it was not wholly a product of more northern latitudes1 but was mostly produced by the snow which fell on the plains during the long winters of that period1 which could not be melted away during the cold summers of an ice age1 when it is considered that an ice-sheet1 with a temperature sufficiently low as to carry glacial drift1 covered the lands of ,missouri as far as latitude #ch south2 and it may have been through the pressure from an ice-sheet in its south-eastern movement that we are to account for the numerous ore-bearing faulting fissures traversing the limestone strata4 ,the ice-sheet was also the probable cause of the erosion of the horizontal bedded stones1 yet it appears that the ice did not greatly change the contour of the ground2 for it is well known that glaciers do move over lands that are not frozen to the ice without causing much disturbance1 especially where the gradient is small1 and this was the probable condition of the ,western plains during the ice age4 ,thus it seems that whatever disturbance this region has undergone could be partly attributed to ice-sheets without the presence of bowlder drift1 because the temperature and texture of the ground in the limestone region were unfavorable for such accumulations2 yet it may be owing to the action of ice that minerals once diffused are now found collected in fissures4 ,the deep valleys through which the large rivers now pass on their way toward the sea were once filled with glaciers which flowed into them from their tributaries4 ,thus the deep trenches of the plains are largely the work of glaciers4 ,it is generally supposed that the driftless region of ,wisconsin was free from ice during the frigid period4 ,but it seems impossible for this region to have escaped being covered by ice and snow1 with the great lakes filled with glaciers1 and the regions on all sides of the driftless area covered with ice4 ,the reason why this territory escaped the drift from the north was on account of the hindrance which the drift-bearing ice-sheet encountered in the deep basin of ,lake ,superior4 ,in this great depression the ice-sheet from the north was relieved of bowlders and other glacial drift1 as well as obstructed in its southern movement4 ,therefore1 the snow and ice which gathered on the driftless region had little movement in any direction1 while the temperature and consistency of the ground under the ice were not favorable for the production of bowlder drift2 and1 when we consider that the ,mississippi valley was deprived of great sources of warmth during the culmination of a glacial period1 we are forced to the conclusion that its wide lands were also covered with snow and ice4 ,the tropical waters of the ,north ,atlantic were so much chilled by the floating icebergs of ,north-eastern ,america1 ,greenland1 ,iceland1 and ,northern ,europe that the ,caribbean ,sea1 its warmest reservoir1 was reduced to a temperature so low that the easterly winds which blew over its waters were unable to prevent ice-sheets from gathering on ,eastern ,nicaragua4 ,therefore1 during such frigid times it appears that1 with the waters of the ,caribbean ,sea and ,gulf of ,mexico reduced to a low temperature1 it was impossible for the great ,mississippi valley to escape glaciation1 while being surrounded by cold seas and glaciated lands which extended even into the tropical latitudes4 ,the broad1 level lands of ,british ,america and ,siberia during the ice age must have been thickly covered by the snow which fell on the deeply frozen plains1 besides the large amount of snow that the cold westerly winds must have drifted over their icy surface from lands of greater snow-fall on their western borders4 ,this snow during such freezing times could not be melted away4 ,the great ice-sheets thus formed over wide1 level lands could have but little motion in any direction1 certainly not sufficient to cause glacial drift of much magnitude2 yet the ice-sheet1 at one stage of its existence1 probably served to widen and deepen the channels of the great rivers which empty into the ,arctic ,ocean from these vast regions1 and the glacial dbris from such erosion was deposited in the arctic seas4 ,,chapter ,v4 ,,remarks ,,on ,,theories ,,advanced ,,for ,,explaining ,,ice ,,periods4 ,on ,nov4 #ab1 #ahia1 ,professor ,geikie made his presidential address before the ,edinburgh ,geological ,society1 the subject being 8,supposed ,causes of the ,glacial ,period40 ,many of his views advanced in this lecture were so much in accordance with my own that ,i am induced to repeat them4 ,he said that the glacial period was a general phenomenon due to some widely acting cause1 and that where we now have the greatest rain-fall the greatest snow-fall took place1 and that the ,pleistocene period was characterized by great oscillations of climate1 extremely cold and very genial conditions alternating4 ,he also said that in glacial and post-glacial times changes in the relative level of the land and sea had taken place1 and any suggested explanation which did not fully account for these various climatic and geographical conditions could not be satisfactory4 ,and1 while examining the earth-movement hypothesis1 he pointed out that in the first place there was not the least evidence of great continental elevations and depressions in the northern hemisphere1 such as the hypothesis postulated4 ,next he showed that1 even if the diserrated earth-movements were admitted1 they would not account for the phenomena4 ,such changes1 no doubt1 would profoundly affect the maritime regions of ,north ,america and ,europe2 but they would not bring about the conditions that obtained at the climax of the ice age4 ,another objection to the earth-movement hypothesis was this3 it did not account for interglacial conditions4 ,the advocates of that hypothesis imagined that these conditions would supervene when the highly elevated northern regions were depressed to their present level4 ,but these were the conditions that obtained at the present time2 and yet in spite of them the climate was neither so equable nor so genial as that which obtained in interglacial times and during the mild stage of the necessary post-glacial period4 ,therefore1 he said that the earth-movement hypothesis should be rejected1 not only because it was highly improbable that such wonderfully rhythmic elevations and depressions of northern lands could have taken place1 but chiefly because it did not explain the conditions of the glacial periods and interglacial times4 ,still1 ,professor ,geikie says that in glacial and in post-glacial times changes in the relative level of the land and sea had taken place2 and it is reasonable to suppose that such changes were obtained in the high latitudes of both hemispheres during the breaking up of the last ice age4 ,we have previously pointed out that much of the ice of the glacial period in the southern hemisphere was melted away1 and its waters warmed sufficiently to assist the ,gulf ,stream and ,japanese current to bring about a mild period in the northern hemisphere2 for without such assistance they would be unable to disperse the vast ice-sheets of the northern latitudes4 ,still1 the attraction of the southern ocean waters into the northern seas must have commenced as soon as the growing ice-sheets of the large continents and islands of the high northern latitudes surpassed the growth and weight of the glaciers on the smaller lands of the southern hemisphere4 ,hence the attraction of the ocean waters northward overcomes the force of the prevailing winds from moving an undue portion of the ocean's surface waters southward4 ,consequently1 the movement of water from the southern seas into the northern latitudes continued so long as the vast northern ice-sheets increased in weight greater than the glaciers of the southern hemisphere4 ,therefore1 at the perfection of a frigid age straits and channels situated so far southward as the ,magellan and ,cape ,horn channels were much diminished in width and depth or entirely deprived of their waters4 ,through this cause such reduced channels were readily filled with glaciers in a region of great snow-fall4 ,the depth of water on the submerged northern lands at the close of the glacial period is not known4 ,according to ,professor ,dawson1 in the township of ,montague in ,ontario the skeleton of a whale was found in post-glacial deposits #ddj feet above tide-water1 and marine shells are known to occur on ,montreal mountain at an elevation of #ebj feet above the ocean2 and it is said that there are traces of submergence of over one thousand feet in the higher latitudes1 including the islands of ,great ,britain4 ,according to the researches of ,dr4 ,j4 ,w4 ,spencer1 one great sheet of water covered most of the great lake region about the close of the ice age2 and the lower strands of these inland seas are known to be connected with old marine shore lines4 ,the probable reason why so few sea-shells collected on the glacial drift during such times was because of so much marine life having been exterminated in the high northern latitudes during the frigid age4 ,therefore1 the sea1 in the short period of northern submergence1 left but few traces on the glacial drift it once flowed4 ,thus it will be seen that1 if the ocean waters were attracted northward through the preponderance of northern ice-sheets1 they not only assisted in melting the northern ice1 but also served to greatly reduce the waters in the ,cape ,horn channel1 and so largely prevented the independent circulation of the southern ocean1 thus furthering a mild climate in the southern hemisphere until the prevailing winds1 after the northern ice-sheets were melted1 were able to move more of the ocean waters southward than they could move northward1 owing to the ocean currents setting southward being less obstructed than the lesser currents setting northward4 ,this tendency of the ocean waters to move southward ,i have before explained in the preceding pages4 ,but ,i will say in addition that1 on further consideration1 it seems that one of the main causes of the waters of the augmented northern oceans moving southward so soon after the melting of the ice from the northern lands was on account of so much water being attracted southward to the great low sea-level east of ,cape ,horn4 ,this vast low sea-level remained a great area of attraction for the northern seas until so much northern water was moved into the southern ocean as to reduce the seas of the northern hemisphere and augment the southern ocean sufficiently to enlarge the ,cape ,horn channel1 thus causing the extinction of the vast low sea-level that furnished such great attraction for the waters of the more northern latitudes4 ,if the earth-movement hypothesis1 so wholly rejected by ,professor ,geikie1 fails to explain the cause or causes of a northern ice age1 it seems to be still more inadequate for explaining the occurrence of ice periods extending over both hemispheres4 ,for it is not probable that portions of continents and large islands rose above the snow-line in both temperate zones during the same period of time1 and then again obtained their present level with the occurrence of a mild era4 ,those who maintain that the continents of ,north ,america and ,europe rose to great elevations during the ice age1 in order to prove their assertions1 point to the fiords which indent the eastern and western coasts of ,north ,america1 and also to the fiords of ,norway1 as having been eroded by streams of ice that flowed along the bottom of such gorges when they were above the sea4 ,but it appears that such erosion could be performed by heavy glaciers with the lands at their present level4 ,a glacier three thousand feet thick would fill and press heavily on the bottom of a gorge fifteen hundred feet in depth4 ,therefore1 should the bottom of a fiord sink hundreds of feet below the sea-level1 a glacier several thousand feet thick flowing through and over it into a sea of much greater depth1 the erosion at the bottom of the sunken channel would be greater than on the land above the sea1 where the ice possessed less weight4 ,therefore1 it is not necessary that lands pierced by deep fiords should have acquired a higher level during the ice age than they now maintain4 ,and it is probable that on the antarctic continent ice erosion may be going on at much greater depths below the sea-level than the deepest channels in the high northern latitudes4 ,for it is likely that the temperature of a glacier is so low in such frigid regions that it holds firmly in its freezing grasp such bowlders as may become detached from the rocks1 thus giving it great erosive power4 ,but this great eroding ability could not be maintained by glaciers in the lower latitudes1 where a higher temperature would largely deprive the ice of its abrading properties except on the steep slopes of mountainous lands4 ,there are deposits of ice on the ,north ,american coast bordering the arctic shores1 and also on ,northern ,siberia1 that are supposed to have existed since the last frigid period1 and are likely to be preserved into a future cold age1 which now appears to have made considerable progress on ,greenland and other ice-clad arctic shores on account of the independent circulation of the ,arctic ,ocean waters1 which largely excludes the ,gulf ,stream from the polar seas2 and it is for this reason that the glaciers on the elevated lands of ,iceland are being enlarged and rapidly advancing4 ,yet1 notwithstanding the gathering of ice and increasing coldness of lands largely removed from the warm ,gulf currents1 there are still mountain regions where glaciers may have been preserved through post-glacial times1 although directly to the leeward and under the influence of the ,gulf ,stream and ,japanese currents4 ,these glaciers are situated in the ,alpine districts of ,europe and on the mountain ranges of ,alaska4 ,it would appear that1 were the climate growing gradually colder in the northern temperate zones1 such glaciers should be increasing in size4 ,yet it is said that such is not always the case4 ,this is probably owing to their being subject to the genial influence of the tropical currents4 ,for1 although the climate of ,europe and ,alaska may have been slowly growing colder for centuries1 still the slow shrinkage of these once immense glaciers may still be going on1 although at a much slower rate than formerly1 even if the tender plants of these latitudes1 because of the growing coldness1 have gradually moved southward4 ,as to the ,alpine glaciers1 ,m4 ,forel reports from data he has collected that there have been several enlargements and diminutions during the last century4 ,and since #ahge enlargements have taken place1 their shrinkage being caused by warm and dry weather1 while their enlargement was brought about during cold and rainy seasons4 ,the glaciers of ,alaska cannot attain much extension until the waters of the great ,japanese stream acquire a lower temperature4 ,there is at this date a small current setting down through the eastern side of ,bering ,strait1 bearing field-ice in the spring season down to ,anadyr ,gulf4 ,the ,okhotsk ,sea in the spring season furnishes considerable field-ice to cool the north ,pacific waters1 and the wintry winds which sweep down from the high lands of ,northern ,asia also serve to chill the ,pacific seas2 but all such sources of cold combined at this age have but little general effect on the vast ,japanese current1 which still has warmth sufficient to prevent the increase of glaciers on ,alaska4 ,this great ocean stream in its impact against the shores of ,oregon causes a high sea-level1 which is mostly turned southward by the prevailing north-west winds4 ,still1 a comparatively small stream sets along the shore of the ,alaska ,gulf1 and also through the island passages toward a slight low sea-level1 to the leeward of the ,alaska peninsula2 and it is probable that this current which warms these in-shore waters is favored by the difference of temperature and density between the waters abreast ,oregon and the ,gulf of ,alaska1 and it may be owing to the same cause that a small stream is sent along the eastern shore of ,bering ,strait into the deep portions of the ,arctic ,ocean4 ,thus because of the warm waters that proceed from the great ,japanese current the glaciers of ,alaska are prevented from increasing their bulk4 ,the only way to furnish the ,japanese stream with colder water1 and so cause glaciers to increase on the north-west coast of ,america1 is through the great ,humboldt current1 which has its rise in the southern ocean west of ,patagonia and the ,cape ,horn channel1 where a moderate but vast high sea-level is formed on account of the great drift current of the southern ocean being somewhat obstructed on its passage through the ,cape ,horn channel1 which is about one-third the breadth of the westerly wind-belt4 ,therefore1 the northern portion of the waters of the high sea-level so caused are attracted northward to the low sea-level abreast ,peru1 from whence they are moved by the south-east trade winds as a drift current to the equatorial latitudes1 thus meeting and mingling with the returning ,japanese current abreast ,central ,america1 and so giving head to the great equatorial stream which moves westward over the ,pacific ,ocean1 partly impelled by the trade winds1 and1 on gaining the western side of the ocean1 sends off from a moderate high sea-level a large stream to the low sea-level caused by the westerly winds abreast ,japan1 from whence it is drifted by the same winds over to the north-west coast of ,america1 thus forming the great ,japanese current4 ,meanwhile the temperature of the ,humboldt current1 being governed by the temperature of the southern ocean from which it takes its rise1 is cooling at a slow rate through the enlargement of ice-sheets in the antarctic regions1 while the increase of glaciers on ,patagonia will in time greatly add to its coolness1 and so lower the temperature of the equatorial current from which the ,japanese current branches1 the latter current being made cooler through the increase of coldness of the former streams4 ,therefore1 the temperature of ,alaska1 which is governed by the ,japanese current1 will slowly acquire a colder climate2 and1 consequently1 its glaciers will increase in size sufficient to launch icebergs into the ,pacific to be currented southward1 and so still further lower the temperature of the ,eastern ,pacific waters1 and consequently the equatorial current from which the ,japanese stream branches1 and so eventually1 under the above conditions1 cause heavy ice-sheets to spread widely over the north-west coast of ,north ,america4 ,it will be seen from the above explanations how an increase of cold in the southern hemisphere is necessary to cause a wider spread of ice-sheets on lands in the northern hemisphere4 ,especially is this the case to promote the gathering of glaciers on the west coast of ,north ,america4 ,the great equatorial current while on its way to the ,indian ,ocean not only sends off the ,japanese stream1 but also the ,east ,australian current1 which is like the ,japanese current1 having its temperature lowered in proportion as the equatorial stream is cooled4 ,therefore1 the southern ocean is slowly being deprived of equatorial heat from this source4 ,i have explained how the increasing coldness of the superior oceans of the southern hemisphere affects more or less the temperature of the ,gulf ,stream1 which meanwhile is only able to enter a small portion of its waters into the ,arctic ,ocean after undergoing a long cooling process as a drift current2 and1 while thus mingling with the arctic waters1 it is not able to prevent the gathering of ice-sheets on ,greenland1 where glaciers are launching bergs to float southward as far as the latitude of #dj north4 ,consequently1 the northern seas are now being cooled as well as the seas of the southern hemisphere4 ,yet this cooling process is so slow there is a lack of data to show that the temperature of the high latitudes is lowering4 ,our thermometrical observations are of such recent date they cannot be used to determine climatic changes which requires centuries to bring about4 ,still1 it is generally known that the climate of ,northern ,europe has been accused of growing colder4 ,the vine no longer flourishes on the shores of ,bristol ,channel or in ,flanders or ,brittany2 and vineyards are no longer planted on the elevated shores of ,france where they flourished three hundred years ago4 ,arago did not refuse to believe that the laws regulating the temperature of ,western ,europe had notably altered4 ,this is proved1 he said1 by the general retrogradation of the vineyards southward4 ,the recent deadly freezing of the orange groves of ,florida makes it uncertain whether the cultivation of the orange can again be successful in the counties where during this generation it has been very profitable4 ,travellers visiting ,iceland say that the old accounts of its prosperity seem strange to those who now visit its shores2 and it is narrated in the ,sagas that in early times sheep could shift for themselves during winter1 and that there were large forests and that corn ripened4 ,several years ago a correspondent of the ,spectator1 writing from ,northern ,russia where the ,volga is locked with ice for six months in the year1 stated that 8the people were beginning to show increased resentment at the climate1 and that there was reason to believe that the northern government of ,russia would be abandoned to the desert4 ,the people silently glide south by the tens of thousands every year1 so the life of ,russia was concentrating in the south40 ,it is now the opinion of travellers in arctic lands that the inhabitants of the ,esquimaux regions are decreasing1 as are also the inhabitants of ,northern ,siberia4 ,a writer in the ,north ,china ,herald1 of ,shanghai1 says that 8the climate of ,asia is becoming colder than it formerly was1 and its tropical animals and plants are retreating southward at a slow rate4 ,in the time of ,confucius elephants were in use on the ,yangtse ,river4 ,a hundred and fifty years after this ,mencius speaks of the tiger1 the leopard1 the rhinoceros1 and the elephant as being in many parts of ,china4 8,it is also said that the ferocious alligator1 that formerly infested the rivers of ,south ,china1 has retreated southward4 8,the flora of the country is also affected by the increasing coldness of the climate4 ,the bamboo is not found in the forests of ,north ,china1 where it grew naturally two thousand years ago1 but is still grown in ,pekin1 with the aid of good shelter1 as a sort of garden plant only40 ,a letter from ,hong ,kong1 published in the ,london ,standard1 reports that on the #aeth of ,january1 #ahic1 the temperature of ,hong ,kong1 a tropical seaport of ,china1 was below freezing for three days1 and was colder than ever before known4 ,the rocks and also vegetation were covered with a coating of ice4 ,the thermometer at times stood at #bc and #bf ,fahrenheit4 ,i have previously explained how the slow increasing coldness of the northern temperate zone is also being carried out in the southern hemisphere4 ,the meteorological records for the lofty table lands of ,ecuador1 although very incomplete1 furnish strong evidence to show that the mean temperature of that region is gradually lowering4 ,observations made by ,boussingault at ,quito in #ahca1 compared with those from #ahgh to #ahha1 showed a decrease from #ae4b ,centigrade to #ac4bg ,centigrade4 ,records made by ,hall from #ahbe to #ahbg give averages of #af4a ,centigrade1 #ae4eb ,centigrade1 and #ae4f ,centigrade4 ,this decrease holds good for all points in the inter-,andean region where records have been kept4 ,yet we know that the falling temperature in the northern temperate latitudes is not brought about by a yearly increase of cold1 because1 when the arctic channels are somewhat obstructed with icebergs1 the movement of arctic waters through them is lessened2 and1 therefore1 during such times the ,gulf ,stream1 meeting with less opposition from arctic currents while flowing northward1 is able to move a larger volume of its waters into the arctic seas1 thus warming their waters sufficiently in a few seasons to clear the obstructed channels1 and also somewhat soften for several successive years the temperature of such lands as border on the seas of that region4 ,and in this way we account for the mild seasons which at times follow those of lower temperature in high northern latitudes4 ,but1 when the detained icebergs are set adrift1 and currented into the temperate ,north ,atlantic1 the heat consumed while melting such numerous bodies of ice is able to more than overcome the warmth gained during the temporary detention of ice in the northern seas4 ,thus1 under such considerations1 it appears that the conditions are favorable for the growth of glaciers in the high northern latitudes4 ,i have pointed out the manner in which the superior oceans in the southern hemisphere are obtaining a lower temperature1 and how they impart their coldness to the tropical currents1 and in this way slowly cool the waters of all oceans4 ,thus it appears that the northern temperate zone1 with all other parts of the earth1 is slowly approaching a cold epoch4 ,several writers on climatic changes have expressed their views as to the number of glacial and mild periods that have been perfected since the conditions have been favorable for their appearance on the globe4 ,according to my views1 while considering the reasons for the occurrence of the great glacial periods which have left such extensive traces on the land1 it seems certain that two very cold epochs have possessed the earth1 separated by a warm period2 and1 possibly1 other preceding cold epochs of less intensity have possessed the high latitudes1 with intervening periods of mildness4 ,but the earlier cold periods1 if they ever existed1 were comparatively short1 because the ,cape ,horn channel during such times possessed less capacity than in the later periods1 and1 therefore1 was more easily and quickly obstructed by the natural methods previously explained4 ,consequently1 the independent circulation of the southern ocean was sooner arrested than during the later epoch1 when the channel had become enlarged by erosion from heavy glaciers and icebergs2 and meanwhile the same conditions may have governed the arctic channels which give an independent circulation to the arctic waters which surround ,greenland1 and thus1 in connection with cold epochs in the southern hemisphere1 have caused periods of cold of small intensity to occur in the high northern latitudes1 and it may happen in the future that more ice periods will be perfected than the one now progressing4 ,still1 it is well to bear in mind that the ,cape ,horn channel1 which is the real cause of glacial periods having occurred in both the northern and southern hemispheres1 in the manner previously explained1 is being made wider and deeper during each succeeding ice age4 ,for this reason the latest cold epoch will require a longer continuance of cold to obstruct the channel than the cold period preceding4 ,therefore1 it appears that the time will come when there will be such great accumulations of ice stored on the land and in the sea before the enlarged ,cape ,horn channel can be closed that1 when it is closed1 there will not be sufficient warmth remaining in the tropical seas to unite with the sun's rays to subdue the intense cold stored in the immense gatherings of ice4 ,and thus the earth1 which began its career with a warm temperature1 and so continued for long ages1 will finally terminate in an endless glacial age4 ,the statements made by ,general ,cowell in ,science of ,nov4 #be1 #ahib1 in reference to the alleged discovery of the second rotation of the earth by ,major-general ,drayson1 represents the discovery as affording a new solution for the cause or causes of an ice age4 ,the second rotation as defined consists in the pole of the heavens describing a circle around a point which is ascertained to be situated six degrees distant from the pole of the ecliptic4 ,and it is asserted that by a knowledge of the second rotation it is proved that a variation of twelve degrees in the extent of the arctic circle and the tropics occurred not later than #ac1ejj ,b4,c41 8the tropics varying in distance from the equator from the minimum of #bc #be #dg to the maximum of #ce #be #dg1 thus extending the torrid zone during its widest expansion from ,cape ,hatteras to the river ,plate4444 ,it is calculated that at this date we are about #djc years distant from the time when the pole of the heavens in its revolution1 the pole of the ecliptic and that of the second rotation1 will be in the same colure1--that is1 in the year #b1bie ,a4,d42 and then the least differences in temperature between summer and winter will be experienced4 ,from that time forward this difference will increase1 and about #f1jjj years later1 or about the year #h1cjj ,a4,d41 the earth will enter the next glacial period1 and attain its greatest severity about the year #ah1acf of our era40 ,general ,cowell does not state how the widening of the tropical zone1 as above set forth1 would bring about a glacial period4 ,the winters of the temperate zones would evidently be colder than now2 but1 on the other hand1 the summers would be proportionally warmer1 while the westerly winds above the latitudes of #dj would prevail the same as now4 ,therefore1 their general effect on the surface waters of the ocean in the high latitudes would not be changed with such an extension of the tropical zone1 neither would the trade winds change their general direction with a wider torrid zone2 yet the boundaries of the trade winds and also the westerly winds would be more shifting according to the declination of the sun1 such winds being governed as now by the position of the sun during the summer and winter solstice4 ,yet the natural process for moving tropical water into the high latitudes1 or excluding it therefrom1 would not be greatly changed4 ,consequently1 the expansion of the torrid zone to the latitudes named by ,general ,drayson would not affect the climate of the hemispheres sufficiently to cause a frigid epoch4 ,on the contrary1 the summer monsoons1 which now blow from the north-east1 along the shores of ,eastern ,africa1 and also along the coast of ,southern ,brazil1 would be much stronger with a vertical sun in midsummer as far south as river ,plate1 thus forcing the surface waters of the tropical oceans into the higher latitudes with greater facility than at this age4 ,moreover1 according to the statements of ,general ,cowell1 the present period of mildness should be on the increase1 and obtain perfection in the year #b1bie1 or about #djj years hence2 while1 on the contrary1 according to the explanations we have given in the preceding pages1 there is much to show that an ice age is advancing1 and has made considerable progress in the high latitudes of both hemispheres4 ,furthermore1 if the second rotation1 as claimed by ,general ,cowell1 is able to perfect a glacial period at regular intervals of #ca1fjj years1 it seems that traces of frigid epochs should not be confined to late geological records1 as there appear to be little or no traces of glacial work prior to the ,quaternary or ,post-tertiary periods4 ,it appears that explanations so far given1 which depend on the astronomical theory to account for the ice age1 are not in harmony with well-known geographical facts4 ,the explainers neglect the attention due to the great prevailing winds which since the earlier geological ages have1 in connection with continents1 moved the surface waters of the ocean from torrid latitudes to colder zones1 and from the colder zones to the warmer latitudes4 ,this exchange of ocean waters between the zones is as old as the continents which shape their courses4 ,the important change wrought in the ocean currents sufficient to have caused the glacial age which ended the early warm epochs was brought about through the action of the prevailing winds1 which1 in connection with the form of continents1 became able to move the ocean waters from the northern hemisphere into the southern sufficient to submerge the low lands of the southern hemisphere1 causing a great diversion of the tropical currents from the high southern latitudes1 such as ,i have pointed out in preceding chapters4 ,those writers who believe that ocean currents have been the cause of great climatic changes have suggested that the existence of an ancient channel through the isthmus of ,panama would have caused a frigid period on lands bordering on the northern shores of the ,atlantic by turning the head-waters of the ,gulf ,stream into the ,pacific ,ocean4 ,professor ,agassiz thinks that such a channel existed during some remote geological age1 judging from the semblance of the fauna pertaining to the ,caribbean ,sea and ,pacific ,ocean4 ,yet it may be said that an open channel through ,central ,america would have connected two high sea-levels4 ,for this reason there would be little or no exchange of water between the ,caribbean ,sea and the ,pacific ,ocean4 ,the high sea-level on the ,pacific side is caused by the prevailing north-west winds which blow down the ,north ,american coast past ,california as far south as ,central ,america2 while1 on the other hand1 the south-east trade winds impel the surface waters of the ,south ,pacific along the coast of ,peru down to the equator1 and so onward #e to #h north latitude4 ,thus the space between the ending of the two ocean winds obtains a high sea-level1 corresponding to the high level of the ,caribbean ,sea4 ,this has been proved from levellings for the ,nicaragua ship canal4 ,consequently1 the ,atlantic waters would not run into the ,pacific ,ocean1 even if a channel opened through ,central ,america4 ,therefore1 the ,gulf ,stream has never been turned away from the ,north ,atlantic4 ,writers1 while seeking a cause for the mild climate of ages preceding the glacial epochs1 have thought that during such times channels opening through ,asia from the ,indian ,ocean by the way of the ,persian ,gulf into the arctic seas would be the means of furnishing the ,arctic ,ocean with warm water4 ,but it is evident that such a movement of water could not be brought about1 because the winds would not be favorable for it4 ,for1 when we reflect that the prevailing winds would blow in the same direction as now1 and that the seas of ,eastern ,europe and ,western ,asia were enlarged during the warm epochs1 it seems that they would obtain high levels superior to the high level seas of the ,indian ,ocean4 ,besides1 we should consider that there is a continuous range of high land separating the ,persian ,gulf from the northern seas1 which probably existed anterior to the ice age4 ,still1 during later periods1 while the ice-sheets were being melted from the northern hemisphere and also on the ending of the last ice age1 the ,isthmus of ,suez was submerged1 as were all other low lands in that latitude2 but it is probable that the waters of the high sea-level of the ,indian ,ocean abreast tropical ,africa did not flow largely into the ,mediterranean ,sea for the reason that the enlarged ,european seas1 being within the westerly wind-belt1 maintained a high sea-level1 while at the same time the high level tropical ,indian ,ocean waters were strongly attracted into the southern oceans through the ,mozambique and ,agulhas currents in the manner ,i have previously explained4 ,yet the waters of the high sea-level of the southern ,european seas must have been strongly attracted to the low sea-level abreast the ,canary ,islands4 ,while considering the causes which brought about the glacial periods1 it is well to reflect that the natural mode of action which could have produced a frigid age was as extensive as the surface of the globe2 and1 therefore1 any geographical change that would affect only a comparatively small portion of the earth cannot serve to account for ages of warmth which extended over the globe1 or for glacial epochs which were separated by warm periods of time1 which seem to have affected all lands and seas4 ,and it appears from the geographical explanations given in preceding pages of the general movements of the winds and currents of the sea how impossible it is for heat to be conveyed to the antarctic latitudes sufficient to prevent the growth of glaciers on their lands while the ,cape ,horn channel is in possession of its present capacity4 ,for1 as has been shown1 this channel furnishes opportunity for the westerly winds to impel the surface waters of the great southern ocean constantly around the globe1 and so largely turns away the tropical currents from the high southern latitudes4 ,consequently1 there seems to be no method yet devised through nature's mode of action that can carry sufficient heat into the antarctic latitudes to melt the ice-sheets from the southern continent1 or even arrest their growth1 while the ,cape ,horn channel maintains its present width and depth4 ,therefore1 the increase of glaciers and icebergs will slowly continue until a glacial epoch is perfected4 ,and it seems that this arrangement for bringing about a frigid age made slower progress in its early stage than at this date1 owing to there having been a lack of glacial ice in the polar regions to produce icebergs for cooling the ocean waters4 ,but the independent circulation of the great southern ocean1 after turning away the tropical currents from the high southern latitudes for thousands of years1 did at length cause glaciers to form on the antarctic lands1 which have been slowly1 but constantly increasing2 and1 consequently1 the cooling of the ocean has been accelerated proportionate to the increase of ice-sheets4 ,therefore1 with the cooling process so well advanced as it now appears to be1 it seems that more than half of the time required to bring a frigid age to perfection has been expended since ice-sheets began to gather on the antarctic shores4 ,for1 when we realise how the facilities for making ice have advanced through the increase of glaciers in both hemispheres1 and how large a portion of the ocean waters have been cooled below a temperate or tropical temperature even in the torrid latitudes where the warm upper waters of the ocean have been reduced to a comparatively thin stratum when compared to the vast bulk of the cooled under-waters1 it appears that the cold will increase at a faster rate for the next thousand years than was the case during the last ten centuries4 ,therefore1 the climate will be less favorable for plants and animals existing on lands in the high latitudes for the next thousand years than during the ten centuries preceding2 and1 when we take into consideration the accelerative growth of a frigid epoch1 it seems that the increasing cold will in a few thousand years drive the greater portion of both plants and animals from the now temperate latitudes to maintain an existence in the tropical zone1 where a large part of the existing species of such life must have taken refuge during the last ice period4 ,and1 from what can be learned from the relics of man's prehistoric life1 it seems to point to the lands of the tropical latitudes as having been his home during the frigid ages2 and1 because of his long undisturbed residence in favored portions of the tropics1 he there attained his earliest civilization4 ,for it appears that the tropical zone was not only less burdened with ice in glacial times than the higher latitudes of the globe1 but was also more exempt from the great flooding of lands which obtained in the more northern latitudes through the shifting of the ocean waters1 from causes set forth in the preceding pages4 ,yet it may be said that the low lands of the tropical zone south of the equator during cold epochs were much more extensive than at this age1 on account of the shrinkage of the sea1 because of the great amount of water evaporated from its surface1 and stored in ice-sheets on the great continents and islands4 ,hence the reefs and shallows which surround such tropical islands as include the ,seychelles ,archipelago1 and also the extensive banks covered with shoal water in that portion of the ,indian ,ocean1 were during the glacial period elevated above the surface of the sea1 possessing a climate favorable for vegetable and animal life4 ,but1 owing to the great rain-fall of that region1 it is probable that the highest lands were glaciated1 as it is reported that granite bowlders still rest on the mountain slopes of the highest island4 ,the numerous islands and shoals of the south-western tropical ,pacific must also have afforded wide land areas1 with a temperate climate1 owing to their having been situated on one of the warmest regions of the earth during the ice age4 ,moreover1 it is probable that these tropical lands afforded space for numerous lagoons which had little connection with the surrounding oceans1 and consequently were able to maintain1 in their secluded shallow basins1 a warmer temperature than obtained in the open seas2 and at the same time1 owing to the great rainfall in such tropical portions of the ,indian and ,pacific regions1 the waters of the lagoons were rendered less salt than the briny depths of the shrunken oceans of a cold period4 ,hence because of such conditions the fauna of the tropical seas were preserved from the destructive rigor which beset the earth during the frigid epochs4 ,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 typographical errors were corrected2 unbalanced quotation marks were remedied when the change was obvious1 and otherwise left unbalanced4