58 Kansas Academy of Science. 



THE CHERT GRAVELS OF EASTERN KANSAS. 



15.V L. ('. A\'()()sti:r. 



WHILE these chert gravels have been seen by the author 

 of this paper in several other counties of eastern Kan- 

 sas, they have been specially studied by him only in Green- 

 wood, Lyon and Morris counties. The general features of 

 this deposit are the same, however, wherever seen. 



These chert gravels are found capping the highest bluffs, 

 are less abundant on their slopes, and are plentiful again in 

 the river and creek channels and beneath the bordering bot- 

 tom lands. The thickness of the deposit varies from nothing 

 up to ten or more feet, and the gravel is usually less than five 

 inches in diameter. Its color varies from light buff, some- 

 times almost white, to a yellowish brown, the gravel longest 

 exposed to the atmosphere averaging darkest in color. Many 

 pieces contain fossils of the common Coal Measure and Lower 

 Permian types. Productus semireticnlatus, Athyris suhtilita, 

 Fusulina cylindrica, and various species o^ cup corals, crinoids 

 and lace corals are most common. 



The chert and the included fossils of the gravel are very 

 similar to the chert and included fossils of the Wreford lime- 

 stone of the "Flint Hills" in the adjacent north-and-south tier 

 of counties to the westward. All the strata in this part of 

 Kansas dip at a low angle to the westward, and the "Flint 

 Hills" are slowly receding in the same direction under the 

 eroding influence of atmospheric and aqueous agencies, and 

 the chert gravel undoubtedly represents the resistant debris 

 of the Wreford and Florence limestones left on the peneplain 

 to the eastward. These Lower Permian limestones stretch 

 across the state in a general north-and-south direction, and, 

 since they must have been receding westward during the 

 twelve million years that have elapsed since the close of the 

 Paleozoic era, when eastern Kansas was lifted out of the seas 

 for the last time, they have left a belt fifty or sixty miles wide 

 strewn more or less thickly with their chert. In the Kansas 

 river valley and north, the drift left by the Kansas glacier lies 

 next above the gravel or is mixed with it. 



Several interesting inferences to the student of geology 

 may be derived from a study of these gravel deposits. 



