94 Kansas Academy of Science. 



a linear arangement and other relations such that they are 

 regarded as having been deposited by the same glacial river. 

 These systems have nearly the same general directions as the 

 continuous osars. Their topographical relations are, also, 

 substantially the same, except that the gravel deposits of 

 which the system is composed are from a few feet up to a 

 mile or more in length and are separated by intervals vary- 

 ing within the same limits. 



Glacial Gravels of the Coastal Region. — The glacial 

 gravels of this type are found in three relations to marine 

 clays: (a) The gravels have the same level as the clays and 

 pass by degrees directly into them. This is the characteris- 

 tic relation of the glacial deltas and marks the coarser glacial 

 sediments as being laid down simultaneously with the clays. 

 (6) The clays overlie the glacial gravels, either wholly cover- 

 ing them or covering their base. The gravels were first de- 

 posited within ice-walls, and subsequently, after the ice 

 melted, the clays were deposited, (c) The sand and gravel 

 of the upper parts of the osar gravels overlie the fossiliferous 

 clays which cover the base of the same kames or osars. These 

 can be accounted for in two ways: (1) The ridges were first 

 deposited within the ice- walls; subsequently the ice melted 

 and sea-water covered them. Moraine clay, or in some cases 

 kame or osar boulder-clay, was laid down. (2) The sand and 

 gravel which overlie the clay on the flanks of the osars may 

 have been brought there by glacial streams. 



Simple Tracks or Patches of Drift Formed by Subgla- 

 cial Drainage. — Thin sheets and lenses of gravel and sand 

 in the midst of subglacial till are common phenomena in gla- 

 cial regions; and, while in many cases they may have been 

 produced by streams running in tunnels which afterwards 

 shifted their position and left no other mark than these patchy 

 deposits, it seems that many of these drift patches were pro- 

 duced by a diffuse and local drainage developed by one of sev- 

 eral combinations of conditions while the ice was still present 

 and continuing its deposit of till. 



SUBMARGINAL DEPOSITS. — Submarginal ridges of till paral- 

 lel with the ice border are often in evidence. These lie along 

 what was the immediate border of the ice at certain stages 

 of its retreat. They are thought to have been formed under 

 the edge of the ice, but it remains to be determined to what 

 extent they were accumulated under the immediate border of 



