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extent. lis most soutlierly border is in Jackson county, and its extent 

 easterly and westerly, from Saginaw Bay to Grand Rapids. Assuming 

 the Saginaw and Maple Rivers as the line of its central axis, and 

 that it extends no further north from this line than its known south- 

 erly limit, the coal beds of Michigan may be considered as embraced 

 in an irregular basin, having a length in its longest axis of about 140 

 miles, and a breadth of 80 to 100 miles, and covering an area probably, 

 of not less than 9,000 square miles. The difficulty of conducting ex- 

 plorations over this large area, owing to the immense accumulation of 

 loose materials which everywhere cover the rocks, has been sufficiently 

 explained in the annual reports alluded to. 



I shall only further, and briefly, allude to the salt deposits of our 

 State. It is generally known that the State made an attempt to develop 

 the manufacture of salt, but the reason of the failure of this attempt, 

 and the fact of the existence of brine of sufficient strength and purity 

 for the profitable manufacture, may not be so well understood. 



The State Geologist early pointed out the fact of the existence of 

 lai'ge salt deposits, and indicated the points at which borings might be 

 most profitably conducted. These were commenced in 1839, at Grand 

 Rapids and Tittabawassa river. Owing to the great expense and difficulty 

 at that time, of obtaining the necessary ftiaterials for the undertaking, no 

 sufficient appropriations were made, and the woi-ks were abandoned 

 when the borings had proceeded to not more than half the depth indi- 

 cated, as that which would be found necessary, the latter being estima- 

 ted at from 600 to 700 feet. Even at the depth reached, on Grand 

 River, (about 300 feet,) the quantity and strength of the brine dis- 

 charged, exceeded that obtained at any of the salt works in the country, 

 except those of New York, being not less than 130 gallons per minute ; 

 of which about 100 gallons contained a bushel of salt. At the same 

 time, a private enterprise, undertaken at Grand Rapids, by the Hon. 

 Lucius Lyon, had conducted borings to a depth of 400 feet, yielding a 

 brine, when the upper fresh waters could be shut off, of which, 

 about 82 gallons contained a bushel of salt. None of these borings, 

 however, had extended into the lower salt rock a sufficient depth to 

 reach the strongest brine, and the great difficulties attending the work, 

 in connection with the small facilities for securing a market, and for 



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