326 



era part of Eaton counties, and portions of Calhoun, Clinton, Shiawas- 

 see, and Genesee. In all of the above named counties they occur in sit. 

 uations which admit of being economically quarried, and may often be 

 obtained in firm blocks of any dimensions required. From this series 

 of sandrocks was furnished the material for the construction of the State 

 Penitentiary at Jackson, and at several places, as at Napoleon, excellent 

 grindstones are manufactured from it. 



' RED OR VARIEGATED SANDSTONE. 



This rock immediately underlies the upper coal and shales. Its out- 

 cropping edge is found in the valley of Grand River, in the northern 

 part of Eaton county, and in the banks of the Lookingglass River, in the 

 adjoining towns of Clinton county, and in township seven north, six 

 west, Ionia county. No fossil plants were discovered in this rock. It 

 Las been employed with advantage as a building material. The entire 

 thickness of the included sandstones must be several hundred feet. 



The following general section will exhibit at one view, the relative 

 order and thickness of all the rocks of our coal measures, above descri- 

 bed, so far as a sub-division of them has been found practicable : 



General Section^ applicable to the Coal Basin of Michigan, 



•Counties of Clintou and Eaton. 



