28 § Mounds.—Siliceous Conglomerate.—Fossil Plants. 
together, obstructing the free passage of the air. It is a good spe- 
cies for coaking, and contains a large portion of carbon for a bitu- 
minous coal, it being about sixty per cent. About one’ hundred 
feet below this, lies the coal bed noted in the foregoing section. 
Mounds.—Natural mounds of sand are common in this part of 
Ohio, evidently thrown up by water, and similar in structure to 
those noticed by Prof. Hitchcock, as common to the tertiary depos- 
its of the west. I observed one near the village of Poland, about 
fifteen feet in height, and from forty to fifty feet in diameter, so com- 
pletely isolated, and of a form so perfectly resembling the barrows 
of the ancient inhabitants, that many believe it to be artificial. It is 
found by the neighboring inhabitants to be a useful depository of 
sand for the manufacture of mortar, &c. 
Siliceous Conglomerate—-Amongst the numerous bowlders of 
this region, I observed several of siliceous, conglomerate, similar in 
structure to the rock found in the Laurel and Alleghany Mountains, 
and used in the manufacture of mill stones. In Geauga County, 
forty miles north, it is found in place, and continues on nearly to 
Lake Erie. It is associated with similar deposits, and is without 
doubt a continuation of the same rock with that found in the moun- 
tain ranges, on the south side of the valley of the Ohio. Some of 
the bowlders are very large, sufficient to make a pair or two of 
mill stones. 
Fossil Plants.—On examining the impressions and casts of fossil 
plants obtained at Mariner’s Mill, I found them to embrace several 
species of Palm, Calamites, Sigillaria, &c., several of them entirely 
new to me, and eminently beautiful. They are so perfect that Mr. 
Mariner, a plain farmer, kept them a number of years to show to his 
neighbors as curiosities. He found them in opening a quarry by the 
side of the stream, for the erection of a mill dam. A little lower 
down in the same rock, opened this spring, are found very perfect 
specimens of a new species of Carpolithus. They are very abun- 
dant, and are imbedded amidst fragments and impressions of various 
coal plants. We obtained about a dozen specimens, some of which 
are very fine, and will be described with a few other interesting gasts 
found here. The rock is a light gray sandstone, similar to that de- 
scribed as lying at the base of the foregoing section in the bed of 
Yellow Creek, and is a continuation of the same deposit. 
