325 

 \ 



UPPER COAL. 



The out-crops of this coal, within that part of the State under con- 

 sideration, are of small extent. It is found at the surface, on and near 

 Gran*.! River, in the northern part of Eaton county, and with its associ- 

 ated shales and sandstones, occupies the central part of the coal basin, 

 probably including the whole of Chnton and Gratiot counties. Except 

 in the extreme south-west corner of the former county, it lies too deep 

 for examination. 



Most of this coal is inferior in quality and thickness to the lower 

 coal. It composes several layers, not exceeding in thickness from one 

 to two feet each, and is embraced in alternating strata of dark gray 

 shales, blue clay, sandstones, and thin beds of argillaceous iron ore, ex- 

 ceeding in the whole 20 feet. 



COAL OF EATON COUNTY. 



Sections of the alternating strata of coal and accompanying rocks, 

 taken on Coal and Grindstone Creeks, were given by Mr. Douglass in 

 his report of last year. As that report contained full local details of all 

 the coal-bearing rocks of Jackson, Ingham and Eaton counties, I shall 

 here allude to the rocks of that portion of the State, only in such a 

 general manner as will be necessary, in order to afford a comprehensive 

 view of the coal measures of our State. By reference to the document 

 alluded to, it will be seen that, though inferior in thickness to the lower 

 coal bed, the several strata of coal exposed on the creeks above men- 

 tioned, have an aggregate thickness of from two to three feet, and will, 

 no doubt, prove of importance under a more settled condition of that 

 portion of the State. 



INCLUDED SANDSTONES OF THE COAL MEASURES. GRAY AND YELLOW 



SANDSTONES. 



The sandrocks included between the upper and lower coal, are mostly 

 of a coai-se, quartzose cljiaracter, and of a light gray or yellow color. 

 Most of the strata are friable, but harden on exposure. They are dis- 

 tinguished from the quartzose sandstone below the lower coal, by con- 

 taining impressions of the coal plants. These are referable chietiy to 

 the genera Lepidodendron, Stigmaria, and Calamites. 



These rocks are found outcropping at numerous points through the 

 northern pait of Jackson county, the western part of Ingham, and east- 



