A. E. Verrill— The Bermuda Islands; Geology. 123 
At certain places along the south shore, as at Whale Bay and 
Great Turtle Bay, various stages in the process of eroding the pro- 
jecting ledges and cliffs into detached pinnacles can be seen; and the 
undercutting of these, between tides, until they fall over, leaving 
Figure 27.—Diagram of shore cliff, d, with connected serpentine atoll, c; a, a, 
living rim of the latter; c’, cavity 8 feet deep. HWm, and LWm, high and 
low-water levels. Slightly altered from A. Agassiz. 
flat-topped ledges, which are converted into the serpuline atolls by 
the formation of the living rim over which the waves dash to exca- 
vate the central cup or pool. This is excavated partly by the impact 
== = 
SS 
Figure 28.—Diagrammatic section of incipient serpuline atoll with central under- 
cut pinnacle of zolian limestone still remaining; a, a’, sections of rim con- 
sisting of living serpulz, etc.; s, s’, the enclosed lagoon or cup; w, w’, tide- 
levels. Original. 
of the descending and whirling water and the sand carried with it, 
and partly by the solvent action of the water. As intimated above 
(p. 74), the waves may often find the beginnings of the pot-holes 
already existing in these limestones. The accompanying diagrams 
are intended to illustrate some of the phases of these methods of 
erosion. 
