The Mammalian Era on Urantia

61:7.1Through­out the glacial pe­riod other ac­tiv­i­ties were in prog­ress, but the ac­tion of the ice over­shad­ows all other phe­nom­ena in the north­ern lat­i­tudes. No other ter­res­trial ac­tiv­ity leaves such char­ac­ter­is­tic ev­i­dence on the to­pog­ra­phy. The dis­tinc­tive boul­ders and sur­face cleav­ages, such as pot­holes, lakes, dis­placed stone, and rock flour, are to be found in con­nec­tion with no other phe­nom­e­non in na­ture. The ice is also re­spon­si­ble for those gen­tle swells, or sur­face un­du­la­tions, known as drum­lins. And a glacier, as it ad­vances, dis­places rivers and changes the whole face of the earth. Glaciers alone leave be­hind them those tell­tale drifts—the ground, lat­eral, and ter­mi­nal moraines. These drifts, par­tic­u­larly the ground moraines, ex­tend from the east­ern seaboard north and west­ward in North Amer­ica and are found in Eu­rope and Siberia.

61:7.2750,000 years ago the fourth ice sheet, a union of the North Amer­i­can cen­tral and east­ern ice fields, was well on its way south; at its height it reached to south­ern Illi­nois, dis­plac­ing the Mis­sis­sippi River fifty miles to the west, and in the east it ex­tended as far south as the Ohio River and cen­tral Penn­syl­va­nia.

61:7.3In Asia the Siberian ice sheet made its south­ern­most in­va­sion, while in Eu­rope the ad­vanc­ing ice stopped just short of the moun­tain bar­rier of the Alps.

61:7.4500,000 years ago, dur­ing the fifth ad­vance of the ice, a new de­vel­op­ment ac­cel­er­ated the course of hu­man evo­lu­tion. Sud­denly and in one gen­er­a­tion the six col­ored races mu­tated from the abo­rig­i­nal hu­man stock. This is a dou­bly im­por­tant date since it also marks the ar­rival of the Plan­e­tary Prince.

61:7.5In North Amer­ica the ad­vanc­ing fifth glacier con­sisted of a com­bined in­va­sion by all three ice cen­ters. The east­ern lobe, how­ever, ex­tended only a short dis­tance be­low the St. Lawrence val­ley, and the west­ern ice sheet made lit­tle south­ern ad­vance. But the cen­tral lobe reached south to cover most of the state of Iowa. In Eu­rope this in­va­sion of the ice was not so ex­ten­sive as the pre­ced­ing one.

61:7.6250,000 years ago the sixth and last glacia­tion be­gan. And de­spite the fact that the north­ern high­lands had be­gun to sink slightly, this was the pe­riod of great­est snow de­po­si­tion on the north­ern ice fields.

61:7.7In this in­va­sion the three great ice sheets co­a­lesced into one vast ice mass, and all of the west­ern moun­tains par­tic­i­pated in this glacial ac­tiv­ity. This was the largest of all ice in­va­sions in North Amer­ica; the ice moved south over fif­teen hun­dred miles from its pres­sure cen­ters, and North Amer­ica ex­pe­ri­enced its low­est tem­per­a­tures.

61:7.8200,000 years ago, dur­ing the ad­vance of the last glacier, there oc­curred an episode which had much to do with the march of events on Uran­tia—the Lu­cifer re­bel­lion.

61:7.9150,000 years ago the sixth and last glacier reached its far­thest points of south­ern ex­ten­sion, the west­ern ice sheet cross­ing just over the Cana­dian bor­der; the cen­tral com­ing down into Kansas, Mis­souri, and Illi­nois; the east­ern sheet ad­vanc­ing south and cov­er­ing the greater por­tion of Penn­syl­va­nia and Ohio.

61:7.10This is the glacier that sent forth the many tongues, or ice lobes, which carved out the pres­ent-day lakes, great and small. Dur­ing its re­treat the North Amer­i­can sys­tem of Great Lakes was pro­duced. And Uran­tian ge­ol­o­gists have very ac­cu­rately de­duced the var­i­ous stages of this de­vel­op­ment and have cor­rectly sur­mised that these bod­ies of wa­ter did, at dif­fer­ent times, empty first into the Mis­sis­sippi val­ley, then east­ward into the Hud­son val­ley, and fi­nally by a north­ern route into the St. Lawrence. It is thirty-seven thou­sand years since the con­nected Great Lakes sys­tem be­gan to empty out over the pres­ent Ni­a­gara route.

61:7.11100,000 years ago, dur­ing the re­treat of the last glacier, the vast po­lar ice sheets be­gan to form, and the cen­ter of ice ac­cu­mu­la­tion moved con­sid­er­ably north­ward. And as long as the po­lar re­gions con­tinue to be cov­ered with ice, it is hardly pos­si­ble for an­other glacial age to oc­cur, re­gard­less of fu­ture land el­e­va­tions or mod­i­fi­ca­tion of ocean cur­rents.

61:7.12This last glacier was one hun­dred thou­sand years ad­vanc­ing, and it re­quired a like span of time to com­plete its north­ern re­treat. The tem­per­ate re­gions have been free from the ice for a lit­tle over fifty thou­sand years.

61:7.13The rig­or­ous glacial pe­riod de­stroyed many species and rad­i­cally changed nu­mer­ous oth­ers. Many were sorely sifted by the to-and-fro mi­gra­tion which was made nec­es­sary by the ad­vanc­ing and re­treat­ing ice. Those an­i­mals which fol­lowed the glaciers back and forth over the land were the bear, bi­son, rein­deer, musk ox, mam­moth, and mastodon.

61:7.14The mam­moth sought the open prairies, but the mastodon pre­ferred the shel­tered fringes of the for­est re­gions. The mam­moth, un­til a late date, ranged from Mex­ico to Canada; the Siberian va­ri­ety be­came wool cov­ered. The mastodon per­sisted in North Amer­ica un­til ex­ter­mi­nated by the red man much as the white man later killed off the bi­son.

61:7.15In North Amer­ica, dur­ing the last glacia­tion, the horse, tapir, llama, and saber-toothed tiger be­came ex­tinct. In their places sloths, ar­madil­los, and wa­ter hogs came up from South Amer­ica.

61:7.16The en­forced mi­gra­tion of life be­fore the ad­vanc­ing ice led to an ex­traor­di­nary com­min­gling of plants and of an­i­mals, and with the re­treat of the fi­nal ice in­va­sion, many arc­tic species of both plants and an­i­mals were left stranded high upon cer­tain moun­tain peaks, whither they had jour­neyed to es­cape de­struc­tion by the glacier. And so, to­day, these dis­lo­cated plants and an­i­mals may be found high up on the Alps of Eu­rope and even on the Ap­palachian Moun­tains of North Amer­ica.

61:7.17The ice age is the last com­pleted ge­o­logic pe­riod, the so-called Pleis­tocene, over two mil­lion years in length.

61:7.1835,000 years ago marks the ter­mi­na­tion of the great ice age ex­cept­ing in the po­lar re­gions of the planet. This date is also sig­nif­i­cant in that it ap­prox­i­mates the ar­rival of a Ma­te­rial Son and Daugh­ter and the be­gin­ning of the Adamic dis­pen­sa­tion, roughly cor­re­spond­ing to the be­gin­ning of the Holocene or post­glacial pe­riod.

61:7.19This nar­ra­tive, ex­tend­ing from the rise of mam­malian life to the re­treat of the ice and on down to his­toric times, cov­ers a span of al­most fifty mil­lion years. This is the last—the cur­rent—ge­o­logic pe­riod and is known to your re­searchers as the Ceno­zoic or re­cent-times era.

61:7.20[Spon­sored by a Res­i­dent Life Car­rier.]