Fluctuations in Level of the Quartzltes. 183 



ON FLUCTUATIONS IN LEVEL OF THE QUARTZ- 

 ITES OF SAUK AND COLUMBIA COUNTIES. 



BY T. C. CHAMBERLIN, M. A. 

 Professor of Natural History, Beloit College. 



In this paper, the level of the ocean will be assumed as a 

 fixed standard, and all changes will be supposed to take place 

 in the quartzite. This, though not a strictly accurate method, 

 is, I believe, tacitly assumed in the literature of geology. 



1. Their original position was submarine and essentially 

 horizontal. This is abundantly demonstrated by ripple marks, 

 lines of rounded, water-worn pebbles, and the phenomena of 

 bedding and lamination, and may be dismissed with the mere 

 statement. 



2. The position assumed was the result of the tilting and 

 metamorphosis of the strata. That this was one of consider- 

 able elevation above the ocean level is more than probable. 

 The sea was shallow during their deposition, as is shown by 

 the mere fact that they were sandstones, and by the evidence 

 quoted above. The sea was also shallow during the Primor- 

 dial period following, as is shown by precisely similar evi- 

 dence. So that, unless great depression accompanied the tilt- 

 ing and metamorphosis, an idea that has never, I think, found 

 a place in geology, a very considerable elevation above the 

 ocean must be supposed. This much at least is certain, a vast 

 amount of denudation took place before it assumed the posi- 

 tion next to be noticed. To understand this lully the two 

 ranges must not be considered as separate and distinct, but as 

 portions of one grand group of strata, by estimate, 15,000 or 

 20,000 feet in thickness. The disassociation of the two ranges 

 seems to have resulted from the fact that previous observa- 



