Fossil Ren f the Mastodon, §e. 321 
able bones of Mastodon, ele) and other extinct quadrupeds, which 
must have visited: these sp when the valley was in its present geo- 
graphical conditon in almost every particular, and which must have been 
mired in them as existing quadrupeds are at present. The Mastodon re- 
mains are most numerous and belong to individuals of all ages. The 
mud is very deep, black, and soft. In places it is seen to rest upon the 
limestone, and at some points it swells up to the height of several feet 
above the general level of the plain and of the river. It is occasionally 
covered by a deposit of yellow clay or loam, resembling the silt of the 
Ohio, which is from ten to twenty feet thick, rising to that height above 
the creek and often terminating abruptly at its edges. This loam has 
all the appearance of having been deposited tranquilly on the surface of 
the morass and of having afterwards suffered denudation. The Masto- 
don and other quadrupeds have been mired before the deposition of the 
incumbent silt, for a considerable number of fossil bones have been 
found by digging through it. . Accompanying the bones are fresh-water 
_and land shells, most of which have been identified by Mr. Anthony 
with species now existing in the same region. 
- Mr. Lyell observes that the surface of the bog is extremely uneven, 
and accounts for it partly by the unequal distribution of the incumbent 
alluvium, which presses with a heavy weight on certain parts of the mo- 
rass, from which other portions of the surface are entirely free. He 
also attributes it in part to the swelling of the bog where it is fully satu- 
tated with water near the springs. 
_ The author is of opinion that the fossil remains of Bigbone Lick are 
~ much more modern than the deposition of the drift, which is not present 
in this district. But although the date of the imbedding of these mam- 
malian fossil remains is so extremely modern, considered geologically, 
it is impossible to say how many thousand years may not have elapsed 
since the Mastodon and other lost species became extinct. They have 
been found at the depth of several feet from the surface, but we have 
no data for estimating the rate at which the boggy ground has increased 
in height, nor do we know how often during floods its upper portion has 
Nn swept away. 
Ohio.—The Ohio River immediately above and below Cincinnati is 
bounded on its right bank by two terraces consisting of sand, gravel and 
loam, the lower terrace consisting of beds supposed to be much newer 
than those of the upper. In the gravelly beds of the higher terrace, 
teeth both of the Mastodon and elephant have been met with. Mr. Lyell 
was assured that a boulder of gneiss, twelve feet in diameter, was found 
Testing on the upper terrace, about four miles north of Cincinnati, and 
that some fragments of granite had been found in a similar situation at 
Vol. xtv1, No. 2.—Jan.—March, 1844. 41 
