592 
APPENDIX, 
[C. 
of tbe earth’s surface), — it would seem that the whole subject 
of these newer calcareous formations requires elucidation: 
and, if the inferences connected with them do not throw con- 
siderable doubt upon some opinions at present generally 
received, they show, at least, that a great deal more is to be 
learned respecting the operations and products of the most 
recent geological epochs, than is commonly supposed. 
Since it appears that the accretion of calcareous matter 
is continually going on at the present time, and has proba- 
bly taken place at all times, the stone thus formed, inde- 
pendent of the organized bodies which it envelopes, will 
afford no criterion of its date, — nor give any very certain clue 
to the revolutions which have subsequently acted upon it. 
But as marine shells are found in the cemented masses, at 
heights above the sea, to which no ordinary natural ope- 
rations could have conveyed them, the elevation of these 
shells to their actual place, (if not that of the rock in 
which they are agglutinated,) must be referred to some 
other agency : — while the perfect preservation of the shells, 
their great quantity, and the abundance of the same spe- 
cies in the same places, make it more probable that they 
lay originally in the situations where we now find them, 
than that they have been transported from any considerable 
distances, or elevated by any very turbulent operation. Cap- 
tain de Freycinet, indeed, mentions that patellae, worn by at- 
trition, and other recent shells, have been found on the west 
coast of New Holland, on the top of a wall of rocks an 
hundred feet above the sea, — evidently brought up by the 
surge during violent storms * ; but such shells are found in 
* Freycinet, p. 187. — The presence of shells in such situations 
may often be ascribed to the birds, which feed on their inhabitants. 
At Madeira, where recent shells are found near the coast at a con- 
