REPORT ON FIELD WORK IN GEOLOGY. 14I 



here to be seen in great abundance. They are uniformly filled with 

 seams which in position are entirely independent of the fissures in 

 the enclosing limestone. When they weather out of the limestone 

 they fall into many fragments corresponding in size very well with 

 the gravel near by. Farther to the west other beds of limestone are 

 particularly noted for the heavy amount of chert they carry. Num- 

 ber 15, in the Neosho river section, lying on the Neosho between 

 Council Grove and Parkerville, and along the Cottonwood river be- 

 tween Strong (;ity and Elmdale is one of these. Quite possibly it is the 

 equivalent of the Fort Riley limestone which is so rich in chert. 



In the second place it has been observed that the gravel usually is 

 most abundant in the vicinity of a limestone system rich in chert, 

 or in places over which such limestone probably has extended. The 

 gravels about Oswego occupy space undoubtedly covered at one 

 time by the Erie limestone; those so abundant about Cotton- 

 wood Falls lie under the earlier extension of system number 15 which 

 carries so much chert. On the other hand the large area occupied 

 by the Cherokee shales has but few places where the chert gravel can 

 be found. 



In the third place we found that many of the rounded surfaces 

 possessed by the gravel are the original curved forms the cherts pos- 

 sessed while in their limestone hosts. This is particularly noticeable 

 at Cottonwood Falls. Countless numbers of these have unmistakably 

 such rounded forms. Some were found with tiaces of the limestone 

 still adhering, others with the curved surfaces still possessing the 

 rough character the chert surfaces have while in the limestone, and 

 which in no particular resemble water-worn surfaces. The nnoinlar 

 parts of the chert often have been worn little more than one would 

 expect to observe on chert masses which had been subject to the 

 weathering agents for long geological periods with such slight move- 

 ments as might well be attributed to local causes. 



It seems very probable, therefore, that in most instances the sur- 

 face gravels of eastern Kansas have been derived from the native 

 limestone systems, and that they are the direct results of the weather- 

 ing of those limestones which, when dissolved and carried away 

 by solvents, have left behind the less soluble chert. The chert 

 boulders of such varied sizes and shapes fell into fragments on 

 account of the numerous fissures everywhere prevalent, and the gravel 

 was the result. As terrain after terrain yielded to the slow but sure 

 processes of disintegration and destruction the irksoluble gravels 

 formed residual products which gradually settled to the lowest 

 level possible, which may have been the summit of a hill, or the bed of 

 a river, or any intermediate position. Here and there the rolling 



