GEOLOGICAL RELATIONS. 181 
Wabash River, in that State. It is a fine sandy marl 
of a yellowish-white color. It occurs on the upland, 
from twenty-five to fifty feet above the bottom land, and 
is reached at the distance of from six to ten feet from 
the surface, and has been penetrated to the depth of 
twenty-five feet without passing through it. It appears 
also on the opposite side of the AY abash in Illinois at 
about the same level, and near Shawneetown, forty miles 
distant, in descending into the bottom land, in a similar 
position. Dr. Owen has learned that a similar deposit 
in an analogous position exists opposite to St. Louis, 
above the American bottom on the Mississippi river, and 
there are said to be indications of a like formation at 
Big-Bone Licks, on the south side of the Ohio River, 
about twenty miles below Cincinnati. The Wabash 
deposit contains, in vast numbers, terrestrial and fluviatile 
shells of the same species as those now existing in the 
surrounding country ; they occur also, as we are informed, 
in strata of marl below the deposit in which the bones 
of the Mastodon are found. 1 Whether all these are 
parts of one continuous deposit, or whether they point 
out the location of several small basins in which a con- 
temporaneous deposition took place, is not yet ascer- 
tained. The fossils which they contain prove, accord- 
1 The number of land and fresh-water shells occurring in the Wabash 
deposit is very great. In a small parcel of the marl which we have exam- 
ined, the following species were noticed. Helix hirsuta, monodon, laby- 
rinthica, I'vneata, thyroidus, tlansa, inflecta. Pupa armifera, contractu. 
Iblii-ina occulta ; together with several species of Limnea, Planorbis, Am- 
nicola, Valvata. 
VOL. I. 47 
