A. Winckell o 



the Saliferous Rocks of Michigan. 



onset; and within two years, twenty-three wells have been bored 

 along the valley of the Saginaw, and new ones are continually 



The following is an average section of the rocks passed through 

 1 the borings in the vicinity of east Saginaw : 



Alluvial and Drift materials, 



" Woodville sandstone," brown and coar 

 , consisting of shales with s 





" Parma sandstone" 



Carboniferous liinestome, often hip-hly arenaceous; ijenerally 



sobelow, .:... : YD" 



''Michigan Salt Group," 170 " 



"Napoleon sandstone," light buff, rather coarse and porous, 110 " 

 Total, 765 



The Napoleon sandstone is underlaid by a red shale which has 

 been pierced 64 feet. 



From East Saginaw the depth of the wells increases southward, 

 toward the center of the general basin ; and also northward, so 

 that in the vicinity of Bay City the bottom of the Napoleon 

 sandstone is found at the depth of 1000 feet. We seem there- 

 fore to have a local basin toward the mouth of the Saginaw 

 river, although the vicinity is ten or fifteen miles nearer the out- 

 cropping margin of the salt basin, which is found at the mouth 

 of the Pigeon river and in Tawas bay, on opposite shores of 

 Saginaw bay.* This local basin is filled by an extraordinary 

 thickening of the shales of the Coal measures, almost exclu- 

 sively. As the Parma sandstone, which furnishes the brine of the 

 first wells at Bay City, is probably the equivalent of the sahfer- 

 ous "Conglomerate" of Ohio, it seems that the supply of brme 

 at this horizon, bears a relation to the thickness of the overlying 

 shales of the Coal measures. It also suggests that in the deeper 

 portions of the general basin, the Coal measures must be found 

 similarly augmented in thickness, and the Parma sandstone sim- 

 ilarly charged with brine. This condition should be looked tor, 

 w-est and northwest into Gratiot and Midland counties. 



The following are analyses of Saginaw valley brines, [f 

 first is by Prof DuBois of the University of Michigan, from the 

 Napoleon sandstone ; the second by Jas. E. Chilton & Co., irom 

 the Parma sandstone. 



* On page 72, vol. i. Geolog. Rep. Wisconsin. Prof. Hall states, undoabt^r 

 through madvertence, that the " HamUton group is known upon Saginaw bay. J" 

 uamu ton group strikes the lake sbores in Thunder and Dttle Traverse bap ms"} 



