18 THE GEOLOGY OF BERMUDA. 
that the great oceanic subsidence recorded by the coral islands of trop- 
ical seas was the counterpart of the great elevation of the continental 
lands in the Glacial Period.* It is not improbably a legitimate follow- 
ing out of this suggestion to recognize, in the three great movements 
which are indicated for at least a part of the North Atlantic basin by 
the geological phenomena of Bermuda, the counterparts of the three 
great movements of the North American continent which have charac- 
terized in American geology the epochs of the Quaternary Age. The 
great subsidence in which the Bermudian atoll was formed, would then 
be recognized as correlative with the Glacial elevation of the continent. 
The epoch of elevation in which the Bermudian lagoon was converted 
into dry land, would correspond with the Champlain subsidence of the 
continent. And the final subsidence, of which Bermudian geology 
affords evidence so manifold, would correspond with the re-elevation of 
the continent which marked the transition to the Terrace or Recent 
Epoch. 
While we may reasonably conclude that Bermuda, in common doubt- 
less with an area of the North Atlantic of very considerable extent, has 
undergone these comprehensive movements, it would be strange if 
there had not occurred at least locally minor oscillations. Such oseil- 
lations may possibly be indicated by the stones reported by Neison as 
occurring in the layers of “red earth” in Ireland Island.t His state- 
ment, however, is Somewhat indefinite. At one locality on the south 
shore, a short distance west of Tucker’s Town, I observed a hard layer 
of rock containing marine shells immediately overlying a soft layer con- 
taining land shells. The clearest evidence, however, of repeated oscil- 
lations of level is afforded by a remarkable locality on the north shore 
of Stock’s Point. The rock which has been quarried there, and which 
now appears in the base of the bluff, is a very hard rock of suberystal- 
line texture and of ferruginous color. It shows vestiges of irregular 
lamination, and contains fossil Helices and no marine fossils. It is 
undoubtedly a drift-rock, like that at Paynter’s Vale. The upper sur- 
face of this rock is exceedingly irregular, giving evidence of much sub- 
aerial erosion preceding the deposition of the overlying strata. It is 
overlain by a remarkable conglomerate, evidently a beach-rock, con- 
taining fragments of the underlying hardened drift-rock, peculiar ferru- 
ginous nodules, compact lumps of “red earth,” and pretty large marine 
* Corals and Coral Islands, pp. 366-372. 
t Op. cit., p. 118. 
