Changes of Level in the Bermuda Islands. — Tarr. 301 
chief advocate of this being Dr. Fewkes.* It is true that in 
places there has been much destruction of the land by wave 
action, and it is also true that the porous rocks are easily hol- 
lowed by the action of underground water; but there are such 
strong objections to this exphmation, and so little in its 
support, that it seems hardly tenable even as a theory. 
This phase of the Bermuda problem has been fully discussed 
by others, and I shall simply state the evidence that appeared 
to me to prove beyond dispute that the irregular outline of 
the Bermudas is the direct result of subsidence of an irregular 
land. 
First among these evidences I siiould offer the very outline 
and topography of the islands as proof of submergence. It is 
as typical an instance of a partly drowned land as can be 
found. The dune hills are in places partly surrounded by salt 
water, in others entirely encomi>assed by it, and in some cases 
entirely submerged. Between the submerged reefs and the 
sand hills there is every gradation. There is every intermediate 
stage from a land valley standing nearly at sea level, to a val- 
ley exactly the same in general features, excepting that salt 
marshes exist in the lowest part, and then to valleys occupied 
by salt water in such a way as to partly or entirelj^ cut off 
portions of a ridge, forming either peninsulas or islands. An 
examination of the map shows this gradation, but a visit to 
the islands, and an examination of their topography, is so 
thoroughly convincing of subsidence that it seems difficult to 
believe that the evidence can be questioned. ' 
Another feature of the topography that appealed to me was 
the abruptness of the coast on the southern shore. There are 
few beaches, the main part of the coast line being wave-cut 
cliffs. Had the reef stood at this level long enough to have 
permitted the carving of the islands into their present irregu- 
lar shape, the wave action would have built beaches in greater 
abundance. If the land is hilly, a sinking coast, or one recent- 
ly lowered, will present a series of cliff's, at the base of which 
beach deposits cannot accumuhite, because the material fur- 
nished to the sea coast has not been sufficient to build beaches 
on the bottom which is sinking, or has recently sunk. 
*Proc. Boston Soc. Nat. Hist., xxiii, 1884-1888, 518-522. Am. Geol., 
v, 1890, 88-100. 
