98 A. FE. Verrill—The Bermuda Islands; Geology. 
usual regular character of the beds and the condition of the con- 
tained fossils indicate rather quiet deposition, not storm formations. 
Another suggested evidence that an elevation of several feet has 
occurred is the peculiar character of the erosion on many of the 
cliffs. A second very marked plane of maximum erosion can often 
be observed 8 to 15 feet above the one situated at or a little above 
the present high-tide level. In many cases the cliffs are thus 
undercut at two levels. This, however, might well be due to the 
action of violent gales, producing waves much larger and more 
powerful than the ordinary ones. Thus a single violent storm will 
often effect more erosion in one day than ordinary storms would do 
in several years. 
In other cases cavernous places or “ovens” of large size have 
been excavated entirely above the reach of ordinary waves. This 
is the case on the islands in land-locked Harrington Sound as well as 
in more exposed situations. It seems at first hardly probable that 
occasional severe storms could effect this kind of erosion at such 
elevations. 
But in many cases such erosions are excavated from beds or 
pockets that are unusually soft, or consist of nearly loose sand, 
so that the mere dashing of the spray, made in a severe storm, 
might be sufficient to rapidly wear away such materials at several 
feet above high tide. Still it must be admitted that the erosion of 
such places as the Cathedral Rocks (fig. 9); the pinnacles of 
Tobacco Bay (fig. 10 and pl. xxii, fig. 1); the Natural Arch ; and 
many other places (pl. xxii, fig. 2), could be more easily explained if 
the islands have actually been raised several feet above their former 
level, in post-pliocene times. To suppose that this took place at 
a more remote period would imply a durability that these rocks do 
not possess, although their durability is very great. (See chap. 20, 
A.) This upper zone of erosion has apparently been removed by 
subsequent erosion on most of the more exposed cliffs, especially 
on the south side. 
We might well expect, also, to find some evidences of wave erosion 
on the ledges around the borders of some of the enclosed lowlands 
‘and bays, where the sea does not now reach. It might have pro- 
duced more or less distinct terraces in such places, if the land had 
remained a long time at a lower level than now. But of course, 
such terraces, had they once existed, may have been mostly or 
entirely removed or obscured by later erosion of the softer rocks 
and soil. 
