A, E. Verrill—The Bermuda Islands; Geology. 161 
[P. bermudensis|, which is the common living snail of the island, 
I obtained in the hardest stone and in the loosest sand; sometimes 
lined with druses of carbonate of lime, sometimes filled with a solid 
cast, at other times slightly cemented together, and frequently 
retaining some colour; in which condition they are generally found, 
as before mentioned, in every part of the colony.” 
This rock was a mass of marine or beach limestone, containing 
fossil corals (see under Devonshire formation below). The fossil 
snails in the cavern with red soil indicate that a mass of soil and 
calcareous sands of earlier origin, and containing these fossil shells, 
was imbedded beneath this mass of beach rock, and by its subsequent 
decomposition, the shells and red clay contained in it were left in 
the space it had occupied. 
This large species appears to have become extinct at the time of 
the great subsidence at the close of the Walsingham period, when 
great changes in the climate and vegetation must have occurred. 
It occurs at almost all the quarries opened in the limestones of 
this formation, especially on the west and southwest sides of Castle 
Harbor, both in the hard limestone and the red-clay breccia filling 
cavities. Also at Bailey Bay, Knapton Hill, etc. 
Poecilozonites Nelsoni Bland, var. Nelsoni Verrill. 
Pecilozonites Nelsoni, var. discoides Gulick, op. cit., p. 416, pl. xxxvi, fig. 
4, 1904. 
P. Nelsoni Pilsbry in Heilprin, ‘‘ The Bermuda Islands,” p. 197, 1889, pl. 16. 
Figure 46. Pirate XXVI, Fiaures 7, 8. 
This variety, in its extreme form, has a low flattened spire, but in 
most other respects differs very little from the more elevated forms 
of the species. Intermediate states frequently occur. It is found 
associated with the high-spired variety, but more often alone, at 
several localities in the vicinity of Castle Harbor and Bailey Bay. 
The last whorls are often distorted. 
Bland’s original description applied strictly to this form, named 
discoides by Gulick. He gave the height as 19™"; diameters 
37 X34™™", which are almost exactly the proportions that Mr. Gulick 
gives for his variety discoides. He gives for one: height, 19™™; 
diameter, 37"; for another, height, 19.5™™; diameter, 39™™. (See 
our fig. 46.) 
