62 Kansas Academy of Science. 



some thousands of years. The downward movement was slow- 

 enough for the mountains to yield enough clay and sand, 

 mostly clay, to fill the basin nearly as fast as the bottom sank. 

 This deposit became the Cherokee shales and sandstone. Long- 

 before the Cherokee shales were all laid down, swampy places 

 existed here and there in eastern Kansas and in eastern Okla- 

 homa, which continued to grow swamp vegetation long enough 

 to make all the peat for all the coal now mined at McAlester, 

 Weir City and Lansing. Nor is this all, for in the sandy places, 

 in the shale, enormous quantities of petroleum and natural 

 gas accumulated, which either originated in the decaying bodies 

 of plants and animals under the sand beds, or poured up 

 through fissures in the bottom of the trough from deep in the 

 interior of the earth, no one is certain which. This great 

 synclinal trough must be still sinking, at least the stress on the 

 strata of shale which filled the syncline is not fully relieved, 

 for bottom shale in the McAlister coal mine buckles up here 

 and there to the great alarm of the miners. 



For four million years after the deposition of the Cherokee 

 shales the eastern third of Kansas changed its physical geog- 

 raphy scores of times, with the shore line much of the time in 

 Missouri and Oklahoma. Scores of times the ocean would be 

 free from clay, and layers of limestone would be laid down, 

 made from the skeletons of plants and animals; then the seas 

 would be deep and muddy and shales would accumulate, or the 

 shore line would advance westward and sand for sandstone 

 would spread over the southern and eastern portions of the 

 state. At times sweet water swamps would exist long enough 

 for peat to form, later to be buried, and finally to become beds 

 of coal such as the Osage bed in Osage county and many others 

 in eastern Kansas. These alternations were repeated so many 

 times that a list of the more important strata would comprise 

 more than fifty names, but every millennium saw some sub- 

 stantial gain, for the shore line was pushed westward nearly 

 one-third across the state when the fourth great time of moun- 

 tain-making came which drove the ocean permanently from the 

 eastern half of the continent. 



WHEN THE APPALACHIAN MOUNTAINS WERE MADE. 



The fourth great period of mountain-making, the Appa- 

 lachian revolution, completed the Appalachian system of moun- 

 tains, elevated somewhat and permanently established the 



