Geological Papers. 109 



paraiso to Milford on the Big Blue, which it followed approximately 

 to the Kansas and the Kansas to the Missouri. 



This may have been the line when the ice was at the maximum; 

 but later lines, which may have been occupied longer when the ice 

 was pausing in its retreat, may be followed now by Logan creek to 

 the Elkhorn, by ancient valley along Sand creek and Wahoo creek 

 in Saunders county, by Salt creek, and over to the Big Blue, near 

 Crete. It is conceivable also that a lake basin may have occupied 

 portions of the route at different times, particularly between the 

 Elkhorn and Blue. 



After reaching the Blue the route is comparatively clear. It 

 followed down the course of that stream with an overflow, either in 

 earlier stage or in time of flood, across to the Little Blue at Fair- 

 bury, Neb., and then down that stream back to the main stream. 

 From the mouth of that stream it followed approximately the course 

 of the Kansas river to the Missouri, at Kansas City. We say ap- 

 proximately, for the stream was at first about 200 feet higher than 

 the present stream and there are numerous cases where channels 

 crossed the present divides between that stream and its southern 

 tributaries, for a distance of ten to fifteen miles in places, from the 

 present Kansas. 



Through Nebraska, stream deposits have not been traced over 

 much of the distance, doubtless partly because diligent search has 

 not yet been made. Along.the Blue and Kansas they are frequently 

 found at different levels. The most characteristic deposits of the 

 higher terraces and channels are strips of boulders mingled with 

 gravel and clay. The boulders are of local limestone mingled with 

 crystalline rocks from the north, particularly the red quartzite be- 

 fore mentioned. 



The highest level of drift terraces is about 1000 feet above sea, 

 at a point southwest of Lawrence; 1050 to 1100 southwest of To- 

 peka, and about 1200 south of Wabaunsee. At Fairbury, Neb., 

 gravel occurs about 1325. To pass over the divide between the 

 Blue and Salt creek an altitude of about 1425 is necessary at Berks, 

 and higher farther north. Probably somewhat greater altitude 

 would surmount the divide between the basin of Salt creek and 

 Platte river nt-ar the northwest corner of Sanders county. North- 

 west of Westpoint, Neb., stratified deposits containing drift occur 

 at less than 1450, but, as suggested before, the line may have fol- 

 lowed up Logan creek. To pass the divide from that stream to 

 the Missouri and mouth of James river would have required 1650 

 at least; and to reach the Missouri by way of Aoway creek, proba- 

 bly 1500 feet. 



