9830 £E. Wilkinson—Native Mercury in Louisiana. 
the same types still live. The types of the Bear River i 
lhis 
have thought was probably due to a failure of the outlet drain- 
age of the waters in which that fauna lived to become perpet- 
uated, in consequence of some subsequent geological changes, 
which necessarily destroyed its branchiferous fauna, with its 
peculiar types. 
f we accept such views as this and still admit the real gene- 
tic relationship of the American, European and African forms 
which have been referred to, it is difficult to understand how 
their wide geographical distribution has been effected, and how 
they have been perpetuated to the present time. An interesting 
question for paleontologists to consider also presents itself in 
this connection, which relates to the assumed equivalency of 
formations which bear similar faunas. There are other reasons 
than the similarity of faunas why we should regard the Amer!- 
can and Hungarian formations which contain Pyrgulifera as of 
coneerned, the living fauna of that lake has an interesting 
homotaxial relationship with those fossil faunas of Europe and 
America which contain the shells that have been referred to the 
genus Pyrgulifera. 
or XXXVII.— On the occurrence of Native Mercury in the 
Uuvium in Louisiana; by Ernest WILkrnson, Ensign 
U.S. Navy. 
1,200 feet. Beyond this distance, the limited time at my dis- 
posal did not allow me to investigate, but the appearance of 
the soil seems to indicate that the metal is gathered around a 
