stone, and small amounts of limestone, together with inferior coal or lignite, and in many regions they contain oil. These layers vary in thickness from 200 feet in some places to 10,000 feet in western North America and numerous European localities. Along the eastern borders of the Rocky Mountains these deposits may be observed in the uptilted foothills.
All over the world these strata are permeated with chalk, and these layers of porous semirock pick up water at upturned outcrops and convey it downward to furnish the water supply of much of the earth's present arid regions.
80,000,000 years ago great disturbances occurred in the earth's crust. The
western advance of the continental drift was coming to a standstill, and the
enormous energy of the sluggish momentum of the hinter continental mass
upcrumpled the Pacific shore line of both North and South America and initiated
profound repercussional changes along the Pacific shores of Asia. This
circumpacific land elevation, which culminated in present-day mountain ranges, is
more than twenty-five thousand miles long. And the upheavals attendant upon
its birth were the greatest surface distortions to take place since life appeared on
Urantia. The lava flows, both above and below ground, were extensive and widespread.
75,000,000 years ago marks the end of the continental drift. From Alaska
to Cape Horn the long Pacific coast mountain ranges were completed, but there
were as yet few peaks.
The backthrust of the halted continental drift continued the elevation of the western plains of North America, while in the east the worn-down Appalachian Mountains of the Atlantic coast region were projected straight up, with little or no tilting.
70,000,000 years ago the crustal distortions connected with the maximum
elevation of the Rocky Mountain region took place. A large segment of rock
was overthrust fifteen miles at the surface in British Columbia; here the
Cambrian rocks are obliquely thrust out over the Cretaceous layers. On the eastern
slope of the Rocky Mountains, near the Canadian border, there was another
spectacular overthrust; here may be found the prelife stone layers shoved out
over the then recent Cretaceous deposits.
This was an age of volcanic activity all over the world, giving rise to numerous small isolated volcanic cones. Submarine volcanoes broke out in the submerged Himalayan region. Much of the rest of Asia, including Siberia, was also still under water.
65,000,000 years ago there occurred one of the greatest lava flows of all
time. The deposition layers of these and preceding lava flows are to be found
all over the Americas, North and South Africa, Australia, and parts of Europe.
The land animals were little changed, but because of greater continental emergence, especially in North America, they rapidly multiplied. North America was the great field of the land-animal evolution of these times, most of Europe being under water.
The climate was still warm and uniform. The arctic regions were enjoying weather much like that of the present climate in central and southern North America.
Great plant-life evolution was taking place. Among the land plants the angiosperms predominated, and many present-day trees first appeared, includ-