WAVERLY GROUP. 9 1. 



paid any attention to the collection of fossils from the shales ; but 

 if so, he had no grounds upon which to attempt a demonstration 

 of their Devonian age. The surface configuration of Ohio is 

 very favorable for the study of the Waverly group ; it forms a 

 chain of hills extending from the north end to the south end of the 

 State, which are deeply intersected by valleys of erosion, presenting 

 on their slopes sections through the whole series in direct, uninter- 

 rupted superposition, and laid open sometimes for miles in extent. 

 Such advantages we do not enjoy in Michigan. The Waverly 

 series was evidently at an earlier period likewise intersected by 

 deep erosions, but during the drift period these valleys became 

 completely filled up again with the rubbish of the drift. Subse- 

 quent erosions denuded some rock beds superficially, in limited 

 spots, but no deep cuts through them are laid open ; our 

 deepest natural sections do not comprise in any one place more 

 than 50 feet of strata, and of a portion of the lower beds of the 

 Waverly series, which is nearly a thousand feet in thickness, we 

 have little more information than what we get from artesian 

 borings by means of the material pumped up in pulverized con- 

 dition, a very imperfect mode of studying a formation, the value 

 of which is even lessened by the negligence with which the 

 r ecords of such borings are generally kept. The lower division of 

 the Waverly group is not a shale formation throughout ; it incloses 

 in several horizons thick masses of porous sandstones, which are of 

 the highest economical value for us, as the repositories of a 

 concentrated salt brine. The brine, however, does not seem to be 

 confined to this lower horizon, but pervades the whole rock 

 series, in which the sand_:rock acts as a sponge, absorbing into its 

 pores the saline liquid and retaining it, if the conditions for its re- 

 tention are otherwise favorable. 



In search of this brine, boring experiments have been made in 

 all parts of the State, while in other deep borings, made for a 

 different purpose, brine has been found accidentally. It has been 

 ascertained by these borings that salt brine is not confined to cer- 

 tain localities or to a certain limited geological horizon, but can 

 be found in all parts of the peninsula which are underlaid by 

 the Waverly group, and at the same spot in higher and lower 

 horizons. 



Incidentally, I have recorded several deep borings, while giving 



