434 TH MEDALS OF CREATION. Cuap. XI. 
of Trigonice and Terebratule, which were filled with mol- 
luskite, and large slabs of the sandstone, full of concre- 
tionary and amorphous masses of the same. The latter, 
Mr. Bensted suggested, may have been derived from the soft 
bodiesof the dead Mollusks, which, having become disengaged 
from their shells and aggregated together, had floated in 
the sea, until they became enveloped in the sand and mud, 
which have gradually consolidated into the arenaceous stone 
termed Kentish Rag. In illustration of this opinion, Mr. 
Bensted directed my attention to the following remarkable 
fact, related in the American Journal of Science :—In the 
year 1836, a fatal epidemic prevailed among the shell-fish of 
the Muskingum River, in the state of Ohio. It commenced 
in April, and continued until June, destroying millions of 
the mollusca that inhabited the beds of the tributary streams, 
and the river. As the animals died, the valves of the shells 
opened, and, decomposition commencing, the muscular ad- 
hesions gave way, and the fleshy portions rose to the surface 
of the water, leaving the shells in the bed of the river. As 
masses of the dead bodies floated down the current, the 
headlands of islands, piles of drifted wood, and the shores 
of the river, in many places, were covered with them ; and 
the air in the vicinity was tainted with the putrid effuvium 
exhaling from these accumulations of decomposing animal 
matter. The cause of the epidemic was unknown. 
“ Now nearly the whole of the shells in the beds of 
Kentish Rag,” Mr. Bensted remarks, “have their shells open, 
as if they were dead before their envelopment in the depo- 
sit. And, from the large quantity of water-worn fragments 
of wood perforated by Pholades imbedded with them, it seems 
probable that this stratum had originally been a sand-bank ~ 
covered with drifted wood and shells, thus presenting a very 
analogous condition to the phenomenon above described.” 
The gelatinous bodies of the 7rigonice, Ostree, Rostellarie, 
Terebratule, &c.; detached from their shells, may have been 
