the Ohio river. Yet these streams all show vastly greater 

 depths for the ages before the glacial epoch, as they are all 

 silted up from one to several hundred feet. There must have 

 been broad and deep water ways through the central and 

 northern portions of Indiana. The uncovered portion of the 

 Wabash trough, shows the trunk drainage from the southern 

 and west central portions. The original surface of Indiana 

 was not a perfect level, but was raised into an arch, the crest 

 of the arch extending from Union county on the eastern border 

 of the state, a little south of the center, to the southern part of 

 Lake county on the western border. The crest of this arch 

 fcrms the limestone ledge over which the Kankakee flows as it 

 emerges from the state, and is most conspiciously shown at 

 Momence, just over the line in Illinois. If the surface of the 

 state were not heavily overlain by drift from glacial ice, this 

 linear arch dividing the state diagonally from southeast to 

 northwest, would probably show the ancient drainage different 

 from what it does today. The waters north of the crest would 

 be led through broad and deep channels northwesterly or 

 westerly out of the north or northwestern corner of the state 

 into the Mississippi valley, or into a great water course sup- 

 posed by geologists to have occupied the region of the great 

 lakes, flowing to the east through Georgian Bay and by the 

 way of the St. Lawrence trough to the sea; the St. Lawrence- 

 valley at that time being a great arm of the sea. 



Borings and excavations through the northern part of the 

 state show pre-glacial valleys at many places, but the miscel- 

 laneous borings heretofore made have not been sufficient to 

 trace their course and termination. In sinking our wells for 

 city water supply, we penetrate a bed of coarse river gravel 

 lying upon the shale or original country rock, which is unques- 

 tionably a pre-glacial river bed of large capacity, and undoubt- 

 edly the trunk stream which afforded drainage for all the terri- 

 tory lying north of the arch or elevation which at that time 

 divided the state into two drainage surfaces. 



These pre-glacial valleys having all been filled, and their 

 gravel bottoms hermetically sealed by clay laid down during 



