160 A, FE. Verrill—The Bermuda Islands; Geology. 
hard, red, calcareous matrix, containing red clay. The shells in this 
cluster are all of the high, conical form, now named variety conoides. 
(See pl. xxvi, fig. 4.) Some of them show color markings, as 
described above. This species is common in the Walsingham dis- 
trict, all along the western and southwestern shores of Castle Har- 
bor, as stated above (see pp. 68-70), and at many other localities. 
Mr. Gulick found it in the ancient sandy strata at his station 818, 
near Tucker’s Town, but not in later deposits of the same kind. It 
was found in great abundance at Ireland Island by Lieut. Nelson 
(1840), who described its occurrence as follows: 
“In the centre of this rock was a cavern; and entangled amongst 
the stalagmitic lining (as well as in that of other caves and crevices), 
or else lying in heaps in the loose red earth within, we found abun- 
Figure 45.—Mass of breccia-like material, containing numerous shells of the 
extinct Nelson’s snail (P. Nelsoni, var. conoides), imbedded in stalagmite 
and indurated red clay from the Walsingham formation. About } natural 
‘size. 
dance of a large and delicate Helix [P. Nelsoni|. In another 
instance upwards of thirty bushels were recovered, without any 
earth among them: a circumstance easily accounted for by the com- 
mon habit of these animals to shelter in holes wherever they can 
find them. I have never seen these creatures alive, nor have I ever 
heard of their having been seen in that state ; but still they were 
found with a smaller Helix deep in the compact rock. This Helix 
