358 T.A. Conrad on American Fossiliferous Strata. 
Art. XXXIV.—Notes on American Fossiliferous Strata ; 
by T. A. Conran. 
from the latter locality, which was presented to me several years 
ago by Henry ©. Lamborne, is found to occur in the bank of 
the Potomac near Alexandria. 
Unio radiatoides Lea, N, Jersey, W. Virginia. 
U. saxulum Morton, do. Ohio. 
U. cariosoides Lea, 
U. nasutoides Lea, do, 
Anodon abyssina Morton, Ohio, 
A, grandinoides Lea, 
Alexandria, Va. 
do. 
discover traces of the rivers and their deposits of the Miocene 
period of this country. Only one species of fresh water Unl- 
valves, and an estuary shell living exclusively in brackish water 
had noted a trace of a river and estuary, before the fossil shells 
They, however, are all lying on their sides. whereas if the 
of the present river were elevated tho Unios would generally 
be found in a vertical position, as we find the Glycimeris in the 
