Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/689

 high mounds of sand, such as those before alluded to, with immense masses of shells imbedded in their upper portions.

Some of the shells, although identical with those now living on different parts of the coast, are not now as numerous on this particular part of the coast as they were when the shell-mounds now under consideration were deposited ; they are, however, still very numerous in other, but somewhat distant, bays.

Some have supposed that these accumulations, at such elevations, are somewhat similar to the " kitchen-middens " of Denmark ; and they wish to account for this immense accumulation of shells by imagining that they are the remains of the feastings of some ancient races who at some time inhabited the sea-coast. But, after a careful study of the locality, I cannot arrive at the same conclusion. These shells, judging from their appearance, must have been deposited by the sea where they are now found. The quartzite has been (as before mentioned) worn away until it forms a long steep slope of some two or three hundred yards. The rush of the tidal waves over the surface of this rock (and they have left evidence of their action) would sweep every thing off it ; and their recoil, carrying the shells and sand to the lower levels, would deposit them there in comparatively quiet water, and thus form the stratum we now find.

Between this spot and Port Elizabeth, there are a number of places where this same band of shells is exposed ; but in these instances there is a deposit of sand many feet thick above it. At the spot to which I am now confining my remarks, however, this upper deposit has been denuded, or blown away, leaving the large masses of shells I have described exposed on the surface. Here and there they look, at first sight, as if they had been placed in piles ; hence, no doubt, the mistaken opinion about them ; but on examining these detached heaps, they are found to be parts of the original deposit, the surrounding and intermediate portions having been worn away, and the shells having become broken and pulverized by atmospheric influences. There can be little doubt that at one time the exposed portions of this shell- deposit were covered, as before suggested, with a thick layer of sand ; for in many parts very large quantities of fossilized roots, stems, and branches are spread over the shells. Specimens of these must, from their perfect state of preservation, have grown on the spot, and could not have been washed from a distance. In some instances, where the sand is left, they are still partially enveloped in it. The probable cause of the change they have undergone has been that the water which permeated through the sandy and shelly soil in which they grew, became so charged with lime that, when the roots &c. decayed, the carbonate of lime itself was deposited, as in a mould, in the spaces left ; and these casts, when the sandy matrix was removed, either by strong winds, which so often prevail along the coast, or by other causes, have been laid bare. I have found the same on the coast to the east of the Great Fish River.

Numbers of teeth and bones are frequently discovered imbedded in this shell-deposit near the Shark's River. The position in which