96 LOWER PENINSULA. 



Hard, calcareous sand rock lO in. 



Shales, dark 2 ft. 



White sand rock mixed with shale 8 '' 



Sand rock 99 " 



Salinometer, 94 degrees. 



Shales generally of bright red color 64 " 



These latter extended as far as the drilling was carried, which 

 was to a depth of over 800 feet. 



Since the time of this first boring, many more than a hun- 

 dred other salt wells have been sunk in Saginaw valley, in all of 

 which about the same general order of superposition of rock beds is 

 observed. The coal measures and the subcarboniferous limestone 

 formation are in all of them superimposed on the salt-bearing sand- 

 rock beds of the Waverly group. A weak brine is found even 

 within the coal measures, but the valuable brines are always found 

 lower, within the Waverly group, at a distance of from 600 to 

 1000 feet below the surface. Beneath the sand rock saturated 

 with the strongest brine there are found in nearly all the wells red- 

 colored shales, which are for the practical salt man a sure guide 

 in his boring that he has reached or nearly passed the salt-pro- 

 ducing level. North of Saginaw River, the same results are ob- 

 tained by deep borings. At Kawkalin, two salt wells have been 

 sunk, one to a depth of 810 feet, the other to 1133 feet. The 

 drift is there about 100 feet thick, then follow about 300 feet 

 of shale and sand rock, with seams^ of coal, then 100 feet of lime- 

 stones and gypsiferous shales. About 700 feet below the surface, 

 a sand rock from 90 to 100 feet in thickness is found, which is sat- 

 urated with a strong brine. In the deeper well, below the sand 

 rock, is a series of red shales. 



Southeast of Saginaw, 6 miles from Bridgeport, a very deep bor- 

 ing has been made lately by Mr. Blackmar. The boring pene- 

 trated 



Drift 90 ft. 



Shale 270 "■ 



Coarse sand rock 90 " 



Brine, 63 degrees. 



Blue shales 45 " 



Red shales 200 " 



Gray arenaceous shale 850 " 



