REPORT ON FIELD WORK IN GEOLOGY. I 29 



shale. We must conclude, therefore, that there is not much evidence 

 favoring the general division of our Coal Measures into two great 

 classes, a marginal one and an interior one, for there is about as much 

 indication of one portion being marginal as another so far as the 

 vertical classifications are concerned. While the heaviest shale beds 

 are at the base of the series, the heaviest limestones are also con- 

 tained in the lower two-fifths, and sandstones are about as extensive 

 in the upper half as in the lower. 



Our work during the past summer was of such a nature that little 

 evidence was gathered regarding nonconformities between different 

 members of the Coal Measure series. One instance was noted near 

 Independence where a channel had been eroded in the upper surface 

 of the limestone and subsequently filled with shale. Quite possibly 

 when careful search is made nonconformities may be found in differ- 

 ent places sufficiently pronounced to justify a classification of the 

 Coal Measures into different groups. 



^he Topoo-raphy of Eastern Kansas. 



ERASMUS HAWQRTH. 



The topographic features of eastern Kansas are entirely free from the 

 modifying effect of the various deposits of glacial origin excepting in 

 the northeastern part of the state, and even here the general surface- 

 features are but slightly modified by them. The topography and 

 surface features are therefore the immediate result of erosion acting 

 upon the stratified rocks of the country, which, as already shown in 

 the i)receding pages, are limestones alternating with shales and sand- 

 stones. The limestones resist decay strongly, the shales yield with 

 remarkable readiness, while the sandstones have intermediate powers 

 of resistance. The vertical distance between the different formations 

 varies greatly, but in general the limestone beds are thin and the 

 shale beds are thick, some of them being over 200 feet. 



Let us now consider what would be the result of the action of the 

 ordinary agents of erosion upon such a system of rocks gently 

 inclined to the northwest, with the surface equally inclined in the 

 opposite direction. The softer materials on the surface would soon 

 be carried away, so that we may disregard them now. Sooner or 

 later fissures in various places would be made through the limestone 

 mantles, and admit the eroding agents to the tender shales beneath. 

 The causes of the fissures may have been various. Orographic move- 

 ments, gentle though they have been in Kansas, in many instances 



