Coal Deposits. 27 



limestone, filled with various species of marine shells, and apparently 

 composed altogether from their broken down fragments. Correct 

 figures of the form and structure of this beautiful fossil, are given 

 in the 29th volume of this Journal, page 14 of the wood cuts, and 

 figure 27. — 4 inches. 



7. Blue, magnesian limestone, breaking into rhombic fragments ; 

 in two beds — upper bed eighteen inches thick; compact, and takes 

 a good polish, similar to bird's-eye marble. Lower bed six inches 

 thick; slaty structure, and filled with shells of the genera Producti, 

 Spiriferi, Ammonites, Encrini, &:c. generally contorted and broken ; 

 upper portion also filled with shells. — 2 feet. 



8. The lime-rock reposes on a deposit of blue, argillaceous shale. 

 When first exposed to the air, this deposit is of the consistence, color 

 and smell of marsh mud. When dry, it takes the structure of shale. 

 It is filled with larger and more numerous specimens of shells simi- 

 lar to those in the lime-rock above. — 6 inches. 



9. Bituminous coal and shale, three feet ; upper half of the de- 

 posit composed of shale, which, on exposure to the air, becomes 

 covered with a thick efflorescence of sulphate of iron and sulphate 

 of magnesia; lower half, tolerably good coal. — 3 feet. 



10. White or light gray sandstone rock, fine and compact, forming 

 here the bed of the creek. A few miles below, and deeper in the 

 bed, this deposit of sandstone contains a vast collection of fossil trop- 

 ical plants, of ferns, palms, fee. 



Coal Deposits. — The coal deposits begin to grow thin, as we ap- 

 proach the table lands between Lake Erie and the waters which run 

 into the Ohio. Over a large portion of this serai-tertiary or diluvian 

 tract, the upper deposit of coal has been torn up and washed away, 

 at the period, and by the same cataclysm which covered this portion 

 of the valley with primitive bowlders and tertiary deposits. It is " 

 found yet in place in several eminences, and especially at a spot, 

 two and a half miles S. W. of Poland, on the sides of an elevated 

 tract, where it crops out, and six miles further south passes under a 

 tamarack and cranberrf swamp of several miles in extent. This 

 swamp lies about one^undred and fifty feet above the general sur- 

 face of the country north of \t. On the sides of this ascent the coal 

 comes to the surface, and is worked, but not extensively. It is 

 about three feet in thickness, and of that quality peculiar to the up- 

 per bed all over the valley of the Ohio, being of a slaty structure 

 and glistening fracture, but when burnt in a grate it melts and runs 



