Coal Deposits. Q7 
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, &c. 
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 semi-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 cranberry swamp of several miles in extent. This 
swamp lies about one hundred and fifty feet above the general sur- 
face of the country north of it. 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 ean fracture, but when burnt in a grate it melts and runs 
