Since these pages have been at the press, Mr.Warburton, by whom the coast of Essex and Norfolk has been examined with great accuracy, has informed me that the fossil bones of the crag are the same with those of the diluvial gravel, including the remains of the elephant, rhinoceros, stag, etc.) (**Footnote.

Some valuable observations on the formation of recent limestone, in beds of shelly marl at the bottom of lakes in Scotland, have been read before the Geological Society by Mr.Lyell, and will appear in the volume of the Transactions now in the press.

See Annals of Philosophy 1825 page 310.) Since it appears that the accretion of calcareous matter is continually going on at the present time, and has probably taken place at all times, the stone thus formed, independent 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 operations 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 species 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.

Captain de Freycinet, indeed, mentions that patellae, worn by attrition, 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 the breccia of Sicily, and in several other places, at heights too great, and their preservation is too perfect, to admit of this mode of conveyance; and to account for their existence in such situations, recourse must be had to more powerful means of transport.
(* Freycinet page 187.

The presence of shells in such situations may often be ascribed to the birds, which feed on their inhabitants.