Pliocene

61:4.1This is the pe­riod of preglacial land el­e­va­tion in North Amer­ica, Eu­rope, and Asia. The land was greatly al­tered in to­pog­ra­phy. Moun­tain ranges were born, streams changed their courses, and iso­lated vol­ca­noes broke out all over the world.

61:4.210,000,000 years ago be­gan an age of wide­spread lo­cal land de­posits on the low­lands of the con­ti­nents, but most of these sed­i­men­ta­tions were later re­moved. Much of Eu­rope, at this time, was still un­der wa­ter, in­clud­ing parts of Eng­land, Bel­gium, and France, and the Med­i­ter­ra­nean Sea cov­ered much of north­ern Africa. In North Amer­ica ex­ten­sive de­po­si­tions were made at the moun­tain bases, in lakes, and in the great land basins. These de­posits av­er­age only about two hun­dred feet, are more or less col­ored, and fos­sils are rare. Two great fresh-wa­ter lakes ex­isted in west­ern North Amer­ica. The Sier­ras were el­e­vat­ing; Shasta, Hood, and Rainier were be­gin­ning their moun­tain ca­reers. But it was not un­til the sub­se­quent ice age that North Amer­ica be­gan its creep to­ward the At­lantic de­pres­sion.

61:4.3For a short time all the land of the world was again joined ex­cept­ing Aus­tralia, and the last great world-wide an­i­mal mi­gra­tion took place. North Amer­ica was con­nected with both South Amer­ica and Asia, and there was a free ex­change of an­i­mal life. Asi­atic sloths, ar­madil­los, an­telopes, and bears en­tered North Amer­ica, while North Amer­i­can camels went to China. Rhinoceroses mi­grated over the whole world ex­cept Aus­tralia and South Amer­ica, but they were ex­tinct in the West­ern Hemi­sphere by the close of this pe­riod.

61:4.4In gen­eral, the life of the pre­ced­ing pe­riod con­tin­ued to evolve and spread. The cat fam­ily dom­i­nated the an­i­mal life, and ma­rine life was al­most at a stand­still. Many of the horses were still three-toed, but the mod­ern types were ar­riv­ing; lla­mas and gi­raf­fe­like camels min­gled with the horses on the graz­ing plains. The gi­raffe ap­peared in Africa, hav­ing just as long a neck then as now. In South Amer­ica sloths, ar­madil­los, anteaters, and the South Amer­i­can type of prim­i­tive mon­keys evolved. Be­fore the con­ti­nents were fi­nally iso­lated, those mas­sive an­i­mals, the mastodons, mi­grated ev­ery­where ex­cept to Aus­tralia.

61:4.55,000,000 years ago the horse evolved as it now is and from North Amer­ica mi­grated to all the world. But the horse had be­come ex­tinct on the con­ti­nent of its ori­gin long be­fore the red man ar­rived.

61:4.6The cli­mate was grad­u­ally get­ting cooler; the land plants were slowly mov­ing south­ward. At first it was the in­creas­ing cold in the north that stopped an­i­mal mi­gra­tions over the north­ern isth­muses; sub­se­quently these North Amer­i­can land bridges went down. Soon af­ter­wards the land con­nec­tion be­tween Africa and South Amer­ica fi­nally sub­merged, and the West­ern Hemi­sphere was iso­lated much as it is to­day. From this time for­ward dis­tinct types of life be­gan to de­velop in the East­ern and West­ern Hemi­spheres.

61:4.7And thus does this pe­riod of al­most ten mil­lion years’ du­ra­tion draw to a close, and not yet has the an­ces­tor of man ap­peared. This is the time usu­ally des­ig­nated as the Pliocene.