15 
served great numbers of Unios, of ony Hs 7 
liar to me, scattered over the cultivated fields, o 
at thedistance of amile or more from the Tennessee 
river, and not nearer to any other stream. It . 
usually supposed by the country pacnie that they 
were left in such situations by the Indians, who Oh 
lected them for the luxury afforded by the ane 
inhabitants; but they appear to be alluvial deposites, 
the result of ancient inundations, as the land on which 
they occur has not been overflowed since that por- 
tion of our country was first cultivated by a civilized 
people. Similar deposites of fresh water shells are 
extensively distributed on river lands in Georgia, 
and they appear to me analogous to those vast beds 
of Rangia cyrenoides, on which the city of Mobile is 
built, and which exist on all the alluvial coast of the 
Gulf of Mexico, between Pensacola and Franklin 
in Louisiana. 
In the southern rivers, great numbers of the 
Naiades are annually destroyed by the rapid subsi- 
dence of the waters, which leaves them exposed to an 
ardent sun. When they have travelled some dis- 
tance and fail to reach the water, they burrow deep 
into the moist gravel, and soon perish 
should not speedily rise. 
the attacks of herons and 
numbers of them. Hogs, 
if the river 
They are also exposed to 
crows, which devour great 
I have been informed, alsa 
