THE GEOLOGY OF BERMUDA. dl 
FOSSILS. 
Fossils of recognizable character are found chiefly in the compara- 
tively scanty deposits of beach-rock. The drift-rock, however, contains 
in abundance shells of several species of land snails, the most common 
being Zonites bermudensis and the perhaps specifically distinct variety 
nelsonit, Helix microdonta, and Helix circumfirmata. Among these it is 
noteworthy that Zonites bermudensis var. nelsonit no longer exists in a 
living state. The other three forms are still abundant residents of the 
islands. Shells of Livona pica are also abundant in the drift-rock, hav- 
ing doubtless been carried up from the water by “soldier” or hermit 
crabs. I have also observed bones of birds and fragments of the shells 
of crabs. The remains of marine shells and corals in the drift-rock are 
usually so finely comminuted as to be unrecognizable. 
The beach-rock in several localities contains marine shells in great 
abundance and variety. Nelson appears to be not far out of the way in 
the statement that ‘‘almost every shell now known in the surrounding 
sea may be found in the rock.”* I made no endeavor to make a com- 
plete collection of the fossils of the beach-rock. I append, however, 
a list of the shells which have been recognized among the specimens of 
rock which I collected to illustrate the geology of the islands. The list 
may be of some interest as indicating:in general the most common spe- 
cies of fossils: 
Mytilus exustus, Linn., 
Pectunculus ; 
Barbatia domingensis, Lam., 
Incina pemmsylvanica, Linn., 
Chama macerophylla, Chem., 
Chama lingua-felis, Reeve, 
Bulla media, Linn., 
Fissurella barbadensis, Gmel., 
Fissurella graeca, Lam., 
Livona pica, Linn., 
Nerita peloronta, Linn., 
Truncatella 
y) 
Vermetus lumbricalis, Linn., 
Tectarius muricatus, Linn., 
Cerithium versicolor, C. B. Ad., 
Cyphoma gibbosa, Linn., 
* Op. cit., p. 114. 
