STATE GEOLOGIST. 



ping. 15 000 cubic yards having beeD aires I 1. and 



I ,800 tons i f plaster taken out from a bed 12 feel thick. At 

 the p esent time from 80 to loo to is are qu irried per daj. 

 The amounts of gypsum i at Detroit during the past 



arc us t illoW 



Tons. 



In m Grand Rapids I 



" Sandusky, 4,001 



tal 10,091 



Unless gypsum should be disc tvered in Monroe* county, the 

 I i along the Southern railroad will continue to be supplied 



Dom Ohio; but th< r portion of the State will soon be 



supplied with gypsum of our own production. 



SALT. 



The manufacture of salt is rapidly assuming a great degree 

 of importance to our State. II the geological indications on 

 srhich I found my opinions are not fallacious, we have the most 

 i nt salit'erous basin upon the continent, east of the 



ssippi As might be expected, too, the strength of the 

 brine i- proportioned to the extent of the basin. 



1 omit any historical notices of the rise and development of 

 this interest fn m the time win n the Stale commenced legisla- 



| w n to the present. Many of the 



disappointments heretofore experienced, might have been avoid- 

 ed by an observance of such practical si qs as are sub- 

 j 



1. The occurrence of a salt spring is a fact of I 

 quen, pi in connection with all the other 



': 



2 B at the outcrops -of the coal measure*, 

 I all ( Iroup 

 I Onbnd up. In Ohio, it al m the 



Hamilton Group and the Hudson River 

 op. 

 3. Only two of tl ■] s will bo found, in ;?, to 



