204 Wisconsin Academy of Sciences, Arts and Letters. 



in the unstratified Champlain deposits farther back. But to the 

 east of Beloit the wells even do not strike rock, so far as I know, 

 and so our deep preglacial valley must have had a width of three 

 to four miles at Beloit, and farther north still greater. This is 

 explicable from the fact that the soft St. Peters sandstone would 

 be easily and extensively undermined by the river, so that the 

 greatest depth of the channel may probably be only along a 

 narrow channel in the middle into which the river cut its way 

 and in which it lay until it was lifted out by the accumulating 

 deposits from the melting glacier, widening as it was lifted higher 

 and higher until it covered the present extensive bottoms. 



The successive levels through which the river sank from this 

 point are three in number, everywhere observable, besides some 

 other terraces intermediate and not so well marked. The present 

 river lies as a narrow stream, in general closely skirting the west- 

 ern blufts and in places running upon the rock itself. The cause 

 of this is detected by careful measurements with the aneroid barom- 

 eter, which shows that the general level of the bottoms is some- 

 what higher on the eastern side than on the western, from which we 

 infer that the rise of land to the north which set the river to cut- 

 ting its terraces, was also, to some extent, a rise to the east of us, 

 tipping the river over against its western bluff. 



These rambling notes are presented not so much in the hope of 

 enlightening as of interesting you in some of the geological ques- 

 tions which have interested us at Beloit. 



