, COAL MEASURES. 1 35 



The deeper strata were alternations of sand rock and shales. 

 At 300 feet below the surface, a copious stream of sweet water was 

 struck, which rises in constant flow to the surface, proving very re- 

 freshing to the laborers of the quafry. 



West and north of Ionia, the coal formation disappears under the 

 drift, and no other borings have been made in these directions by 

 which we could ascertain the extent of its distribution as the surface 

 rock. To encounter the coal formation again, we have to return 

 eastward. In Ingham County, shale beds inclosing a coal seam come 

 to the surface on Cedar River, near Williamston ; not far off from 

 this exposure, a shaft has been sunk, and for several years past a 

 mine has been in operation which produces a good quality of 

 bituminous coal. The shaft commences in a drift-mass 15 feet 

 thick ; right under the drift a coal seam of 20 inches is found ; 

 next to this is fire-clay with seams of sand rock, 12 feet; black shale, 

 3 feet ; white, soft fire-clay, 3 feet ; kidney ore, 6 inches ; black, slate- 

 like shales containing Lingula, Discina, Productus, and compressed 

 Lamellibranches, 2 feet ; coal from 3 to 3^ feet ; fire-clay, 4 feet ; the 

 shaft extends about 12 feet below the coal seam, through gray 

 shales. A seam of pyrites is generally connected with the coal, but 

 can be easily separated ; otherwise the coal is tolerably clear of py- 

 rites. Specimens of Sigillaria and Lepidodedron are common in 

 the pyritous seam. Besides the vertical shaft, a sloping gallery is 

 driven to the bottom of the mine, in which the sequence of the rock 

 strata can be studied most commodiously. Mr, Rush, the agent of 

 the coal mine, has explored the vicinity of Williamston for coal, 

 and kindly gave me the results of his experiments, which I set 

 down here. In a boring 4 miles west of Williamston, close to the 

 river, were found, 



Drift 18 ft. 



Black slate 4 " 



Coal 2i " 



Fire-clay 6 " 



Black shale 12 " 



Shaly sandstone 10 " 



Half a mile south from the latter place a boring went 60 feet 

 through drift, without reaching the older rock beds. 

 A boring at the railroad depot of Williamston gave i 



