112 Kansas Academy of Science. 



a year. The Missouri is estimated to discharge an annual average 

 of 24.41 cubic miles. Let the drainage from the west be counted 

 as somewhat more than at present, because of a moister climate then, 

 and we can readily believe that the Kansas of that time may have 

 averaged five times the present Missouri, with possibly ten times 

 in unusual years. 



2. The country rock of the region is mainly shale and shaly 

 sandstone. The limestone comprises less than one-tenth and is in 

 comparatively thin layers and small blocks. Such an arrangement 

 affords conditions very favorable for rapid erosion. 



3. It was probably a time of greater variation of volume in 

 streams and also of frequent freezing and thawing. Both tended 

 to increase the erosion. 



What corrasion such a stream would accomplish can scarcely be 

 conceived, but it may be believed to have been fully adequate to 

 the work supposed. 



Again, the length of time during which this line of drainage 

 was occupied was long. Students of glacial deposits tell us that 

 since the culmination of the Kansan ice the time has been from 

 330,000 to 1,000,000 years. A meager 1000 years might be allowed 

 for the life of the great stream which we have sketched, and, from 

 considerations we have entertained, it would seem much less time 

 might be sufficient to excavate the valleys as we now find them. 

 The chief delay was doubtless the cutting down of the heavy lime- 

 stones which lie athwart the course of the Missouri river in eastern 

 Missouri. 



This discussion is but a preliminary sketch of the problems in- 

 volved in Kansas Pleistocene geology. Our inferences are tenta- 

 tive only. Careful study may modify them in unexpected ways, 

 yet we believe we are on the right track in several particulars. 

 The cooperation of all interested in the subject is hopefully solic- 

 ited. 



