A. EF. Verril—The Bermuda Islunds; Geology. 81 
in Castle Harbor, or in the shallows off the south shore.* The other 
shells give equal proof of having been deposited in comparatively 
still water. On the southerly side of the old fort, an apparently 
complete physical break between the intermediate rock and the sand- 
stone is indicated by a horizontal line, vet the passage from the 
lower to the upper rock is extremely gradual, while above the line 
and within the felix zone, Arca and Chama were seen perfectly 
preserved, the open valves of 1vca, in one case, being still attached. 
The condition, for a time at least, must have been such as one sees 
at Tuckertown today, where the dune is encroaching upon the bay.” 
16. ‘Evidences of Subsidence. 
That these islands have undergone a considerable amount of sub- 
sidence, since the time of Greater Bermuda, is admitted by every 
geologist who has studied them, but they differ as to the probable 
amount. The evidence is partly derived from (A), the wolian lime- 
stones, peat bogs, red soil, land snails, ete., dug up from far beneath 
the sea at Ireland Island, and in dredging and blasting the ship 
channels; (B) from the fact that caverns, sinks, and peat bogs on the 
land now extend much below sea-level, although they must have 
been formed above it. Stalagmites and stalactites, formed in the air, 
are now found submerged in the sea water in the caves; (C) from the 
submarine sinks, sounds, and deep water channels, which give every 
evidence of having been formed by running water when the Jand 
was elevated above the sea. The latter are, no doubt, the more 
important evidences, but the former appeal more to those who are 
not geologists. 
A. KHvidences from submerged dolian limestones and Peat bogs. 
During the excavations made in 1870, at the dockyard on Ireland 
Island, to accommodate the great floating dock, series of solian 
limestones were penetrated to the depth of 52 feet below low tide. 
At the depth of 46 feet below sea-level, a stratum of peat and “red- 
earth,” 2 feet thick, was found, which contained vertical stumps of 
cedar trees. Below this were again strata of hard xolian limestones, 
at least 4 feet thick, containing fossil land-snails (said to have been 
P. Nelsoni by some; P. Bermudensis by others). I have not seen 
* Prof. Stevenson was probably misinformed as to its existence in these locali- 
ties. So far as I know it is extinct in Bermuda, 
