56 Kansas Academy of Science. 



Most of the heated gases on escaping from the earth's in- 

 terior made various chemical unions on reaching the cooler 

 crust and served various uses in nature's laboratory. It has 

 recently been learned that the water of tropical Atlantic ocean 

 is twice as rich in oxygen at a depth of 4000 feet as at 400 

 feet.* This may be partly explained by regarding the crust 

 of the earth beneath the ocean as a storehouse of oxygen. 



The earth's nucleus and the planetesimals in the spiral 

 nebula were probably cold, according to Chamberlin, but the 

 force pulling the tiny solids towards the center of the mass 

 became in time so great that the nucleus with the inner plan- 

 etesimals became very hot under the compressing force. The 

 surface of the earth, however, remained cold and solid, except 

 where the molten interior poured forth through fissures and 

 buried the crust beneath great sheets of molten lava. In the 

 earlier history of the earth this happened so frequently and 

 at so many places that little, if any, of the primitive crust 

 remains at the surface. 



AND HIGH LAND APPEARED. 



So far as the geologist now knows, the first permanent high 

 land to appear above the general level of the earth's crust in 

 what is now North America arose as great mountain ranges, 

 which (1) stretched along our Atlantic border; (2) bounded 

 Hudson Bay on the east, south and west; (3) followed the 

 general course of what are now the Rocky Mountains; and (4) 

 reared aloft granite summits a little east of where are now 

 the Sierras. 



The winds and rains of a moisture-laden atmosphere and the 

 waves of mighty seas and oceans beat upon these great moun- 

 tains for fifteen or twenty million years, wearing them down 

 and sorting and scattering debris in the seas and oceans till 

 low-lying mountains, bordered by shallow-water sand flats and 

 mud flats, were all that remained of the mighty ranges of 

 granite and lava. Before these mountains were formed, life 

 may have established itself in the seas and oceans. No one 

 knows whence it came, but the geologist finds evidence that the 

 waters teemed with life in the Archeozoic era ; first plants, and 

 then animals of simple organization. 



While the mountains were being denuded in the Proterozoic 

 era, worms and primitive crustaceans had their habitats on 



* Science, October 17, 1913, p. 546. 



