VIRGINIA.

For the student of Pleistocene vertebrate palæontology, as for the geologist, Virginia may be divided into three physiographic regions, the Coastal Plain, the Piedmont Plateau, and the Appalachian Mountains. The line which divides the Coastal Plain from the Piedmont Plateau begins at the southern boundary of the State, at about 77° 31′ longitude. The towns on or not far from this nearly north-and-south line are Emporia, Petersburg, Richmond, Hanover, and Fredericksburg. Near the latter the line inclines slightly eastward and passes a few miles west of Alexandria and Washington, D. C. The Coastal Plain is much less elevated than the region west of it and consists of deposits of Mesozoic or Cenozoic age, and much of it is covered by Pleistocene materials. The Plateau region is elevated and consists mostly of Palæozoic rocks, mostly metamorphosed into a crystalline condition. The Appalachian region presents nearly parallel ranges of mountains and intervening valleys.

For a knowledge of the Pleistocene geology of the Coastal Plain the reader should consult Bulletin iv, 1912, of the Virginia Geological Survey. The authors who discuss the physiography and geology of this region are William B. Clark and Benjamin L. Miller. On pages 19 to 45 they present a very full bibliography of the geological literature pertaining to this region. Additional valuable assistance may be obtained from the various folios issued by the United States Geological Survey, but unfortunately not many species of vertebrate animals have been found on this Coastal Plain of Virginia.

In Bulletin IV, already mentioned, Clark and Miller recognize the presence of three terraces belonging to the Pleistocene. To these are given the names applied in Maryland and North Carolina to what are regarded as equivalent terraces. The oldest of these, most elevated and farthest from the coast, is the Sunderland; eastward of this lies the Wicomico; the Talbot is the youngest and lowest and borders the coast. Unfortunately, the geologists referred to did not map the areas occupied individually or collectively by these terraces. They accept the theory that these terraces were laid down in the sea. It is admitted, nevertheless, that no marine fossils are found in deposits of the Sunderland and Wicomico. In the Talbot, 26 species of marine mollusks have been reported from Talbot deposits of the Dismal Swamp Canal, all regarded as belonging to living species. It will be recollected that Woolman (Proc. Acad. Nat. Sci. Phila., 1898, p. 414), in a study of mollusks collected in the Dismal Swamp Canal, found 7 extinct species in a collection of 49 species, equal to about 16 per cent. It is, however, not unlikely that the collections had been dredged up from deeper deposits.

In Bulletin V of the Virginia Geological Survey, on page 25, Sanford stated that the Talbot had a width of 30 miles at the south. On consulting Stephenson’s map of the superficial formations of the Coastal Plain in North Carolina (North Carolina Geol. Surv., vol. III, plate XIII) it will be seen that this corresponds quite exactly with the width of the Pamlico formation at that line. For the writer’s views on the terraces named the reader may consult page 346 on the geology of Maryland.

On page [113] is recorded the discovery of a tooth of a mastodon in a marsh near Disputanta, in Prince George’s County. Not enough is known about the geology of the region to say more than that the deposit belongs to the Pleistocene.

About 6 miles east of Williamsburg, a little more than 100 years ago, remains which pretty certainly belonged to the genus Mammut and probably to the species M. americanum (p. [113]) were discovered, said to have been found on the banks of York River; but by this was probably meant the banks of the flood-plain. The bones were found in marsh mud and were surrounded by roots of cypress trees. The adjacent bank was 20 feet higher than this level. The topographical map of the Williamsburg Quadrangle shows that an abrupt rise of this amount is to be found only about 10 miles away from the river. Whether the cypress roots were those of trees that had grown within recent years or whether they were remains of a Pleistocene forest, such as was exposed at Tappahannock, Essex County (Bull. IV, p. 186), the writer does not know. The information at hand about this case does not make it possible to pronounce on the geological age of the mastodon.

On page [28] an account is given of the discovery of a skull of a walrus on the Atlantic coast of Virginia, at Accomac. It had doubtless been washed up by the sea from a Pleistocene deposit. It is easiest to suppose that the walrus had been driven southward along the coast during the Wisconsin glacial stage; but possibly this happened during an earlier glacial time.

No vertebrate fossils of Pleistocene age appear to have come to light anywhere on the Piedmont Plateau, and little or nothing is known about its Pleistocene geology.

From the geological surveys we get little information about the Pleistocene formations of the Appalachian region. At most, mention is made of soils of undetermined age along the streams; and yet from this region have been obtained a very considerable number of Pleistocene vertebrates.

From Mr. Wyndham Robinson, of Abingdon, Washington County, the U. S. National Museum received in 1869 a tooth of Mammut americanum (p. [113]) and one of Equus complicatus (p. [189]). Nothing has been learned regarding the conditions under which they were unearthed. The horse-tooth points to an age preceding the Wisconsin drift.

From Saltville, in Smyth County, the following forms have been obtained:

That a crocodile should have lived in this region during the Pleistocene is remarkable. Megalonyx dissimilis is otherwise known only from Natchez, Mississippi, from deposits which appear to be of about Illinoian or Sangamon age. The horse-tooth points to about this time or earlier, while the other species do not contradict this conclusion. The astragalus referred to Odocoileus probably belongs to some other genus.

Mr. M. D. Mount sent to the U. S. National Museum remains of Bison (p. [259]), Mammut americanum (p. [113]), and Elephas primigenius (p. [145]). These, he reported, had been found at a depth not greater than 8 feet in excavating for the city reservoir. He has written that the valley of Holston River at Saltville, within about 80 years, had been a lake, at least at certain times of the year, and that the reservoir was excavated at the margin of this low area.

Mr. O. A. Peterson (Ann. Carnegie Mus., vol. XI, 1917, pp. 469–474) reported from this place the crocodile, the megalonyx, cervalces, the supposed deer, the horse-tooth, and remains of mastodons. The bones were found in a sink-hole, in a layer of coarse gravel, pebbles and cobblestones, a fact indicating that a stream of some size had occupied the place. Overlying this layer was one in which there were fragments of large river shells. The bone layer appears to have been only about 4 feet from the surface. Peterson concluded that at the close of the Pleistocene or later the remains had been moved and redeposited from some place not far away, but this would not affect the geological age of the fossils and it is evident that remains of vertebrates are widely dispersed in that valley. All the species reported are extinct, but only large forms were secured.

Professor Cope, probably in 1868, found the following 24 species. He did not state the localities exactly, except that they were along New River, in Wythe County. Two were on the land of Abraham Painter. The writer applied to the surveyor of the county named and has been informed that the farm which belonged to Abraham Painter is on New River, near the town of Ivanhoe. The nomenclature of the species has been revised. The species preceded by a dagger are extinct.

At least 9 of the 24 species are extinct. None of the recorded species requires us to refer the deposit to early Pleistocene times. Ursus amplidens was described from the deposits at Natchez. This and Tapirus haysii, Equus complicatus, and Mylohyus nasutus point to middle Pleistocene, apparently about to Illinoian or Sangamon times.

Cope reported that the teeth and bones were found in a cave breccia. This consisted of a number of irregular masses which occupied “depressions and short galleries” in the southeast side of a line of hills. When those masses were excavated from their beds the floor and roof of a portion of a cave were exposed, with the stalactites, stalagmites, and usual incrustations. It would appear, therefore, that at some time in the early Pleistocene or in the late Pliocene the caves had been formed through the effect of streams of carbonated waters on the limestone; that in some way the bones and teeth of the animals listed above had got into the cave; that by a change in the amount or character of the water the caves had gradually filled up; and that afterwards the limestone which contained these caves had undergone great erosion.

Further north, in the valley of Jackson River at Covington, there is evidently a deposit of Pleistocene clay, for in it at a depth of 12 feet was found a tooth of a mastodon (p. [114]). Another mastodon tooth was found near Hot Springs, at the head of Wilson Creek, in Bath County, possibly in similar deposits (p. [114]). In Augusta County an unidentified species of horse (p. [190]) and the peccary Platygonus (p. [221]) have been discovered.