Fig. 19.-Part of the right side of the lower jaw of an undetermined species of wolf, showing premolar. Charleston, S. C. ×1.
Within the city of Charleston the bed bearing vertebrate fossils is said to be several feet below tide-level. At Young Island, Wadmalaw Sound, nearly 20 miles southwest of Charleston, the top of the fossil-bearing stratum is at tide-level. This locality is otherwise known in the literature as Simmons’s. The only Pleistocene vertebrate fossils that the writer finds reported from the place are the fishes Lepisosteus osseus and Trichiurus lepturus.
In the region about Beaufort, the same fossil-bearing stratum, having about the same composition and the same elevation, is met with in many places. A few species of fossil vertebrates and many invertebrates have been secured. Here have been found Mammut americanum (p. [118]), Elephas columbi (p. [155]), Equus complicatus (p. [191]), and Megalonyx jeffersonii (p. [35]).
A brief notice will be taken of the few known localities where, away from the immediate coast, vertebrate fossils have come to light.
Tuomey, in 1848 (Rep. Geol. South Carolina, p. 177), in describing marls found near Darlington, on the farm of G. W. Dargan, and which he regarded as belonging to the Pliocene, reported the discovery of two perfect molars of a mastodon (p. [118]). The locality was in a swamp, and the bed of marl was covered with 3 or 4 feet of black mud. The teeth were immediately below the mud and enveloped in the marl. These teeth belonged to Mammut americanum and had been deposited at some time during the Pleistocene. At another place fragments of the antlers of a deer were found in the marl. In such cases the marls formed at one time the surface of the ground, or more probably the bottom of a swamp; and the Pleistocene bones and teeth might have been trampled down into the marl by living animals. On page [119] is given an account of another mastodon tooth discovered in the same county; and the teeth of a horse have been reported as having been found, associated with those of the mastodon (see p. [193]).
In Lee County, adjoining Darlington County on the southwest, at a locality “near Concord church,” between Lynch’s Creek and Black River, Tuomey (op. cit., p. 178) found a bed of Pliocene marl about 4 feet thick. From an excavation in this marl had been taken a tusk which Tuomey regarded as that of a mastodon, but this may have belonged to an elephant. In Berkeley County, at the head of Cooper River, there is, or was, a morass known as Biggin Swamp. This was passed through in constructing the Santee Canal. On page [156] is an account of the discovery of remains of Elephas columbi and of Mammut americanum; on page [162], the finding of a tooth of Elephas imperator. The discovery of the latter marks the age of the deposits as being about that of the Aftonian interglacial.
It has been seen that at many points along the coast there is a fossiliferous stratum varying from 2 to 8 feet. At most localities the fossils consist principally of marine animals, especially mollusks, and the deposits have evidently been laid down in salt water. Along Ashley River and at some localities in the region about Beaufort it seems evident that the surface was above, but not far above, sea-level, and that it formed a swamp on which a great variety of land animals could move about and feed. After death their bones would suffer the fate which befalls them in such cases. Most of them would undergo decay. Parts would be trampled into the muck, broken into fragments, and undergo still further decay. Only the most durable parts, as the teeth, antlers, and the more solid bones would usually stand a chance for preservation. Apparently, on this coast, no considerable parts of one skeleton have ever been found, or at least reported. In Charleston Museum are many bones of a skeleton of Megatherium, but it is uncertain where it was found.
The list of vertebrates referred to the Pleistocene of the South Carolina coast contains 33 species of mammals, of which 24 appear to be extinct. This high proportion of extinct species seems to confirm our reference of the fauna to the early Pleistocene. Besides the extinct forms, it is to be noted that within historical times the muskrat, beaver, and elk have not lived in the region about Charleston.
Pugh (Pleist. Deposits S. C., p. 66), from a study of the Pleistocene marine mollusca of South Carolina, has concluded that, if the Pleistocene sea-temperature differed at all from that of the present, it was slightly higher rather than slightly lower. It must be remembered, however, that the Pleistocene represented a very long period of time and that, farther north, the climate underwent great fluctuations. That these fluctuations would not have affected the temperature of the sea along the coast of the Carolinas is not probable. It is hardly supposable that capybaras and manatees lived about Charleston at the same time that the moose and the walrus were there. The latter had been forced down there during some glacial stage, possibly the Wisconsin; while the horses, tapirs, elephants, manatees, the mylodon, and the megatherium had their existence, we may suppose, about the time of the Aftonian. During this stage, too, lived the species of mollusks which Pugh has elaborated. It would seem that after that time some change took place in conditions, probably a slight elevation, so that little more than beds of unfossiliferous sand and marls were deposited.