HAWORTH: the stratigraphy of the KANSAS COAI, MEASURES. 287 



abundance of fossils is generally found near the summit of the 

 several limestone systems. Further, it is well known that the fossils 

 rarely extend into the shales immediately overlying the limestone, 

 that when fossil bearing shales are found they usually are separated 

 from the fossiliferous limestone by a barren area of variable thick- 

 ness, although there are a few notable exceptions which have been 

 mentioned, such as the bituminous shales just above the Fort Scott 

 cement rock, and the exceedingly fossiliferous shales first above the 

 Cottonwood Falls limestone. It would seem that such conditions can 

 best be explained by considering that each limestone forming period 

 was brought to a close by a sufficient elevation of the ocean bottom 

 either to destroy the various existing forms of invertebrate life, or to 

 cause them to migrate to deeper waters beyond the limits of the Coal 

 Measure area as now exposed. Had the climatic conditions on the 

 existing dry-land area changed so as to produce greater erosion, and 

 the consequent greater sedimentation, thereby destroying the inver- 

 tebrate life, the most opportune conditions would then have obtained 

 for the preservation of the shells of the different animals whose lives 

 were thus destroyed. 



It would therefore seem that the conditions in Kansas reciuire many 

 gentle oscillations, both subsidence and elevation, with the greatest 

 movement to the west, and the least to the east. In this way we 

 would expect to find different systems of different kinds of rocks 

 possessing a wedge shai)ed outline with the edges to the east. Such is 

 almost universally the case. In two cases thin limestones have been 

 found which entirely disappear eastward without being cutoff by 

 erosion. One is a limestone covering considerable portions of the 

 surface from i to 2 miles east of Mound City. It completely disap- 

 pears before Pleasanton is reached, and does not appear in the walls 

 of the bluffs between the two towns. The other comes to a feather 

 edge in the bank by the side of the wagon road just south of Hillsdale. 



Winslow* has discussed this subject for Missouri, and coal fields in 

 general, and has shown how many features like those observed in 

 Kansas may be ex|:)Iained by assumptions similar to those above 

 made. The almost perfect continuity over such wide areas of our 

 limestone systems and great shale beds, as revealed by the drill, 

 teach, however, that the oscillations occurred in such a manner that 

 unconformities of any considerable extent were not produced. For 

 a full discussion of this phase of the subject the reader is referred to 

 the article above mentioned by Winslow, pages 23 to 32 inclusive, 

 and to a more elaborate article by the same author in the l^ulletin of 

 the American Geological Society, volume three. 



♦Preliminary Rep. on Coal: Mo. Geol. Surv. ]H • 



