412 PROCEEDINGS OF THE ACADEMY OF [April, 
Pecilozonites reinianus than are now living. The largest specimens 
even of Pecilozonites circumfirmatus and Succinea bermudensis are 
among the fossils. These snails must have found more food than there 
is now on the uncultivated ground. There is also geologic evidence 
that they belonged to a more prosperous epoch than the present. Prof. 
Heilprin reports that in excavations for one of the docks, specimens 
of Pecilozonites nelsoni were brought up from a peat deposit at a depth 
of forty feet below water. A rise of the land sufficient to put these 
shells ten feet above sea-level (see Map No. 1) would multiply the land 
area eight or ten times, changing it from a narrow ridge, hardly two 
miles wide at its widest, into an elliptical area, including, it is true, some 
large lagoons, but in all about ten miles across and more than twenty 
miles long. A large, protected interior valley would then receive the 
fertile soil that is now washed into the lagoon by every storm. It 
would not surprise me if the deposits at locality 807 should be shown 
to date from the period of this Greater Bermuda, but a person need 
hardly wait for this proof before supposing that the indigenous con- 
temporaries of Pecilozonites nelsoni were also characteristic of Greater 
Bermuda. 
In spite of their evident prosperity, I do not think it could be proved 
that these snails lived under any densely shading vegetation. The 
humidity at Bermuda makes such a shade less necessary for snails 
than it is in many places. I have often seen Succinea bermudensis 
clinging to grass and to trunks of trees in such situations that I imagine 
an American summer day would have desiccated them. The tract 
about Prospect Hill (No. 809) must have been desolate, unshaded land 
when the hills were growing dunes, yet the sand here (localities 808 
and 809) contains numerous well-developed specimens and quite a 
variety of species. These must either have lived where they are found, 
or else have been blown there from some place almost equally wind- 
swept. 
The extinction of species that were able to prosper on those barren 
parts of the island seems to me a strange occurrence. If, as I believe 
is probable, the sand for these dunes came from near the present north 
shore, then the island must have had very nearly its present shape 
and size when these snails were alive. Thus when the Greater Bermuda 
sank, the change seems to have set new dunes in motion across this 
section of the Lesser Bermuda; and Pecilozonites zonatus, Cary- 
chium bermudense and Euconulus turbinatus not merely survived the 
subsidence, but even formed a considerable population on the parts of 
the remaining island that were most damaged by the changing condi- 
