Chapter XVII: On the Theory of the Pleistocene Terraces of the Coastal Plain (21)

On page 254 an account is given of finding a musk-ox skull near Steubenville, Ohio, on a terrace about 75 feet above the low-water mark. The region of the western part of West Virginia, western Pennsylvania, and northeastern Ohio is interesting because of its history during the late Pleistocene. The reader is referred to Leverett’s monograph, “The Glacial Formations and Drainage Features of the Erie and Ohio Basins” (Monogr. U. S. Geol. Surv., vol. XLI, 1902, pp. 88–158, with figs.). Leverett essays to show that the upper part of the Ohio River, the Allegheny, and the Monongahela with its branches at one time emptied into Lake Erie. The connection was made through Beaver River, which now flows into the Ohio, and Grand River, in eastern Ohio, now emptying into Lake Erie. When the Wisconsin ice filled Lake Erie and occupied its southern shore the mouth of Grand River was dammed and the water could escape only to the south. The flow was reversed, and after it had reached the top of the divide it entered the stream that then represented the head of the Ohio. When at length the mouth of Grand River was reopened, the new channel had been cut so deep that most of the streams of western Pennsylvania and West Virginia continued to flow down the Ohio. Leverett’s figure representing the preglacial drainage of the upper Ohio region is here reproduced (fig. 10).

NORTH CAROLINA.

(Map 39.)

Our knowledge of the Pleistocene geology of North Carolina is at present confined almost wholly to the Coastal Plain of the State. The most recent general discussions of the geology of this region are found in volume III of the North Carolina Geological and Economic Survey, 1912. The authors who contributed to this volume are William Bullock Clark, Benjamin L. Miller, L. W. Stephenson, B. L. Johnson, and Horatio N. Parker. L. W. Stephenson has furnished an article on the Cretaceous deposits, and in his numerous geological sections he has referred to the Pleistocene materials there found. Benjamin L. Miller wrote on the Tertiary formations and likewise noted the Pleistocene materials found in his sections. The most important part of the volume for the student of the Pleistocene is Stephenson’s article on “The Quaternary Formations,” which occupies pages 266 to 290. Clark, Miller, and Stephenson united in a chapter on the “Geological History of the Coastal Plain of North Carolina.” Clark, besides, deals with the “Correlation of the Coastal Plain Formations.” In addition to numerous plates and text-figures, a colored map shows the area covered by the surficial formations of the Coastal Plain and another the distribution of the formations exclusive of the surficial. Finally, Miller and Stephenson presented a bibliography which includes 150 titles, occupying pages 44 to 73.

According to Clark and Stephenson, the Pleistocene of North Carolina comprises five formations; the oldest is the Coharie, farthest removed from the coast and lying back against the so-called Lafayette, itself supposed, with some doubt, to belong to the Pliocene. Toward the coast there come in, in succession of position and time, the Sunderland, the Wicomico, the Chowan, and the Pamlico. These formations are described as forming more or less well-defined terraces having higher and higher elevations as they are followed back from the coast. The Pamlico nowhere exceeds 25 feet above sea-level. The Chowan varies in elevation from about 25 feet to about 50 feet. The Wicomico formation slopes from about 50 feet up to about 90 or 100 feet. The Wicomico may attain elevations of from 140 to 150 feet at the western border. The Coharie varies from about 160 feet along its eastern border to as much as 235 feet along its western border. From its western border each formation sends up the rivers prolongations into or across the next formation toward the west.

Each terrace may present along its coastward border an escarpment of varying elevation and obviousness. The Coharie and Sunderland formations are regarded by the authors named as being correlated with the Sunderland of Virginia and Maryland, although the Coharie may be really Pliocene. The Wicomico is equivalent to that called by the same name in the States farther north, while the Chowan and the Pamlico together are correlated with the Talbot of Virginia and Maryland.

The area occupied by the Pamlico is extremely narrow or absent along the southernmost third of the coast of the State. At longitude 77° the boundary between it and the Chowan turns and runs north, very slightly to the east, striking the northern boundary of the State at about 76° 15′. Just south of Albemarle Sound its width east and west is nearly equal to that of all the other Pleistocene formations at that latitude, taken together.

Clark, Miller, and Stephenson (op. cit., p. 300) accept the theory of McGee that during Lafayette times, probably in the late Pliocene, the Coastal Plain was depressed some 500 feet below its present level and covered by the sea. Into this sea were poured, by the rivers coming down from the higher lands to the west, the clay, sand, and gravel, sometimes boulders, which make up the so-called Lafayette. Somewhat later the region was uplifted enough to expose the Lafayette deposits and they suffered erosion. When the Coharie formation began to be laid down the sea-level must have been about 160 feet higher than at present; it continued to rise until it reached an elevation of about 200 feet. A subsidence and a succeeding elevation occurred, during which the Sunderland terrace was produced. In like manner the succeeding deposits and terraces are supposed, by the geologists named, to have been formed—the Wicomico, the Chowan, and the Pamlico.

One objection already offered (p. 346) to this theory to account for the deposits belonging to the Lafayette and the formations of the Pleistocene is that, instead of beds of sea-shells, remains of marine fishes, porpoises, and whales, there are found scattered here and there over this region the bones and teeth of elephants, mastodons, horses, and other land animals. In maintaining this objection it is not necessary to assume that the lower parts of the Pleistocene area have never been submerged.

The writer has caused to be prepared a map showing the geographical distribution of the five formations referred (in the work cited) to the Pleistocene. It is based on the maps found in that volume. It shows also the localities where fossil vertebrates have been discovered, and where marine fossils and land plants have been secured (map 39).

One difficulty met with in our study of the distribution of the finds of extinct vertebrates in North Carolina, as elsewhere, arises from carelessness in recording and preserving proper data. In several cases here to be considered, no more is known than that a fossil has been found in a certain county. Happily, more is known in many other cases.

Examination shows that no fossil vertebrates are known to have been found in North Carolina within the area of the Coharie formation, but that mastodons have been met with in the areas of all four of the other formations as laid down in Stephenson’s map, plate XIII of the work cited above. Horse remains, too, seem to have occurred within all the areas last noted. This does not mean necessarily that these remains were buried in the corresponding formations. A mastodon may have lived long after the Sunderland was laid down and his remains have become buried in some isolated deposit, say of Pamlico times; or, the remains may be found within the area of Pamlico, but really buried in underlying Chowan. Each case must be decided on the evidence bearing on it.

Mention is made on page 155 of the finding of a tooth of _Elephas columbi_ about 9 miles below Wilmington. Whether this was buried in Pamlico deposits close along Cape Fear River, in Chowan deposits which prevail there, or beneath these, in Wicomico, it is impossible to say. A short distance below this place was found a tooth of _Mammut americanum_.

On page 190 is given an account of the discovery of a tooth of _Equus leidyi_ in what was supposed to be Miocene marl in the vicinity of Elizabethtown, on Cape Fear River, in Bladen County. Miller (op. cit., p. 248) states that the Pleistocene about Elizabethtown rests usually directly on the Cretaceous, but that south of the town are found some patches of Miocene marls. The region about this town is mostly occupied by the Sunderland formation, but the Wicomico extends up the river far above the place. It is, however, mapped as lying mostly on the north side of the river. It seems pretty certain that the horse-tooth occurred in the Sunderland, probably at its base.

Mastodon remains, as stated on page 115, have been found in Pender County, but where is not known. Along the coast is a narrow strip of Pamlico. The southeastern half of the county is occupied by the Chowan, the northwestern by the Wicomico.

Mastodon teeth have been found in Duplin County, but there is no record as to exact locality, depth, or matrix. The southeastern two-thirds of the county is covered by deposits of the Wicomico, the northwestern third by Sunderland. The mastodon probably belongs to one or the other of these. The Pleistocene deposits are, however, underlain by Tertiary rocks, and possibly the mastodon came from these and belongs to a different genus.

On page 116 will be found an account of remains of a mastodon, probably _Mammut americanum_, which was found near Jacksonville, in Onslow County. Three of the supposed Pleistocene formations are found near Jacksonville. The Pamlico comes up the New River quite to the town. Immediately at the town is (following Stephenson’s map) the Chowan. The southeastern border of the Wicomico comes down nearly to the town. In which of the three areas the teeth were discovered we do not know. A case is here furnished which illustrates the need of most accurate observation and record of locality, depth, and character of materials.

As stated on page 116, teeth and tusks of _Mammut americanum_ have been obtained at Maysville, Jones County. The writer does not know exactly the place where the remains were discovered. The region about Maysville is occupied by the Chowan formation, but the Pamlico sends an extension up White Oak River as far as Maysville.

Remains of both _Mammut_ and _Elephas_ have been reported from Carteret County. In 1828 (see p. 117) Elisha Mitchell stated that remains of the elephant and mastodon had been met with in digging the Clubfoot and Harlow Canal. This canal passed from Neuse River to Newport River. In 1876 (Senate Ex. Doc. No. 35, 44th Congr., p. 17) S. T. Abert transcribed, from an earlier report made by Professor Olmstead, a geological section taken in this canal. The excavation went to a depth of 16 feet. The uppermost of the four layers consisted of the peaty mold usually found in the swamp. The next layer was made up of a yellowish-brown potter’s clay. The third layer consisted of sand and was full of sea-shells and fossil remains of “mammoths” (mastodons) and elephants. The shells belonged to species now found near Cape Lookout, principally conch, scallop, and clam. The layer below this was blue clay. In the case here presented there can hardly be a doubt that the stratum containing the shells and the bones belonged to a Pleistocene formation older than that assigned to the Pamlico.

On page 145 is described a tooth of _Elephas primigenius_, dredged up in Core Creek, forming part of the Inland Waterway in Carteret County. The conclusion seems unavoidable that this boreal animal had been driven to this southern latitude during one of the glacial stages, and one naturally thinks of the latest one, the Wisconsin; but it may have been at a much earlier time. A mastodon jaw has been secured in the same canal.

Doubtless the locality in North Carolina, the most important to the student of Pleistocene vertebrate palæontology, is that reported long ago on the northern shore of Neuse River, 16 miles below Newbern. As stated on page 117, in a mention of the mastodon bones discovered, H. B. Croom seems first to publish a statement concerning the animal remains found there. Some of his identifications were certainly wrong. According to Harlan (Amer. Jour. Sci., vol. XLIII, 1842, p. 143), there were secured remains of elephant, mastodon, hog, elk, deer, horse, seal, cetaceans, a tortoise, snake, fish, shark, and skate. As in another case, Harlan may have mistaken worn teeth of _Bison_ for teeth of the hog (_Sus_). For our purpose the most important animals of the list are the elephant, the mastodon, and the horse. According to Croom, the animal remains were found in a marl pit. He was informed by the owner that in an upper layer there were found teeth of sharks and fragments of bones of marine fishes, mingled with sea-shells. In a deeper layer, 20 to 25 feet below the surface, there occurred the remains of land animals, together with sea-shells of great variety. Croom thought that some teeth belong to the hyena, and Foster reported the hippopotamus; but in both cases the identifications were wrong.

Conrad (Amer. Jour. Sci., vol. XXVIII, 1835, pp. 107–110; Proc. Nat. Inst. Prom. Sci., vol I, pp. 191–192) reported that the bones of animals found here were water-worn, black, and silicified. He concluded that they had been brought down the Neuse River and mingled with sea-shells. The fossiliferous stratum did not rise anywhere more than 10 feet above the river. In the first publication quoted, Conrad published a list of 66 mollusks in this stratum, of which 7 were not yet known as living species and 2 others are noted as new. According to this list, less than 90 per cent are recent. He referred the deposits to his newer Pliocene. In the second publication cited he concluded that the stratum belonged to the post-Pliocene. Stephenson (op. cit., p. 289) refers to the investigations made at this locality. It is not improbable that the deposit which furnished these fossils belongs to the earliest Pleistocene stage, the Nebraskan. The same may be said about the coquina rock mentioned by Stephenson which occurs at Old Fort Fisher, in New Hanover County (op. cit., p. 289, plate XXVIII).

On page 115 the writer refers to a lower jaw of a mastodon found by the geologist W. C. Kerr, near Goldsboro, and described by Joseph Leidy. The jaw was reported to have been found in gravel overlying Miocene marl. The writer believes that the mastodon belonged to the species _Mammut progenium_. Goldsboro, on Neuse River, is near the western border of the Sunderland formation, but the Wicomico is prolonged up the river far above Goldsboro. According to Stephenson and Johnson (op. cit., p. 475), Miocene sands and clays are found over a portion of the northern part of the county (Wayne). The geological age of this mastodon depends more on the age of the gravels in which it was found than on the age of the terrace, although the writer is willing to concede an early Pleistocene stage for the terrace.

A mastodon tooth has been found (see p. 117) somewhere in Wilson County. The county is covered mostly by Pleistocene of Sunderland age, but a small part of the western end is occupied by the Coharie; while, according to Stephenson’s map, both the Chowan and the Wicomico follow up Contentnea Creek into Wilson County. The geological age of the mastodon is doubtful.

At Greenville, Pitt County, have been found remains of _Equus complicatus_, perhaps also of another species of horse (see p. 191). While supposed to have been found in Miocene marls, the tooth belonged without doubt to the Pleistocene. Pitt County is occupied by four Pleistocene formations, Pamlico, Chowan, Wicomico, and Sunderland. The probability is that the horse-teeth were found in an early Pleistocene deposit.

As indicated on page 117, remains of _Mammut americanum_ have been found in Pitt County, possibly at Greenville.

As noted on page 117, a tooth of _Mammut americanum_ has been found at or near Tarboro. Nothing more is known about its origin. At this place are found deposits belonging to the Chowan, Wicomico, and Sunderland formations; it is impossible to say from which the tooth was derived.

Emmons (Geol. Surv. North Carolina, 1852, p. 56) reported finding mastodon bones in marl-pits on the farm of Mr. Knight, on the banks of Tar River, in Nash County, 3 miles west of Rocky Mount. The same Pleistocene deposits occur here as at Tarboro. The bones were supposed to have been buried in Miocene marl, and this may have been true. If so, they belonged to some other species of mastodon than _Mammut americanum_.

On page 191 is given an account of the discovery of teeth of _Equus leidyi_ which were washed up on the beach at Plymouth. This town is on Roanoke River, several miles from Albemarle Sound, and on the border between the Pamlico and the Chowan formations. Our determination of the geological age of the teeth must be based on other evidence than that furnished by the discoverers.

Elsewhere in this work is given an account of finding a part of a skull of a walrus at Kitty Hawk. It was probably during the Wisconsin glacial stage that this animal lived along the coast as far south as Charleston.

As to the geological age of the Pamlico formation, the geologists who have contributed to the report of 1912, the volume cited, hold that it belongs to late Pleistocene. The writer believes that the formation was laid down at a much earlier time. The mastodon jaw and the tooth of _Elephas primigenius_ found in the Inland Waterway Canal may have been buried there during the prevalence of the Wisconsin ice epoch; but, on the other hand, this may have happened during an older Pleistocene stage.

It will be observed that the Pamlico becomes very narrow along the southern third of the coast of North Carolina. In South Carolina it may be represented by one of the older Pleistocene deposits recorded by Sloan; in part possibly by the Wando clays or the Sea island sands. In the author’s view, it is pretty certain that the Pleistocene molluscan fauna which had been found in the Clubfoot and Harlow Canal and at the locality below Newbern corresponds to the Wadmalaw in the vicinity of Charleston. It seems to appear at the southeastern corner of the State, at Southport, and again in the northeastern corner in Dismal Swamp. According to Shaler (10th Ann. Rep. U. S. Geol. Surv., pt. I, 1890, p. 315), a collection of mollusks made near the northern border of the swamp was submitted to Dr. W. H. Dall. There were 29 forms, of which 24 are yet existing, 5 extinct. There were, therefore, 17 per cent of extinct forms. Dall regarded the deposits as belonging to the Pliocene; the writer believes that they may be referred to the Nebraskan stage of the Pleistocene.

From a study of mollusks collected later in the Dismal Swamp Canal, Woolman (Proc. Acad. Nat. Sci. Phila., 1898, pp. 414–428) concluded that they belonged to a time not earlier than late Pliocene and possibly as late as the Pleistocene. Darton (U. S. Geol. Surv., Folio 80) referred the deposits to the Pliocene. Stephenson (op. cit., p. 290) states that recent investigations have led to the conclusion that the beds should be referred to the Pleistocene. The parties in such a dispute may compromise by referring the beds to the Nebraskan stage. It seems probable that the Chowan formation belongs to a stage a little later than these mollusk-bearing beds and represents a strip of old coast marsh, inhabited by elephants, mastodons, horses, and various other animals.

In discussing the causes which led to the production of Cape Hatteras, Professor Shaler (Proc. Bost. Soc. Nat. Hist., vol XIV, 1872, p. 117) remarked that the hard shelly limestone which comes to the surface just above high-tide level along the shore of the mainland from Newbern to the mouth of the Roanoke River looks much like the shell-bed found near Charleston, South Carolina.

SOUTH CAROLINA.

To the reader who wishes to know what work has been done on the Pleistocene geology of South Carolina, two papers may be recommended. The first of these, historical in nature, was published in 1890 by Professor Joseph A. Holmes (Jour. Elisha Mitchell Sci. Soc., vol. VII, pp. 89–117), the second in 1905 by Dr. Griffith T. Pugh (Thesis, Vanderbilt Univ., pp. 1–74). Those who have contributed most to a knowledge of the palæontology of this formation are Tuomey, F. S. Holmes, Leidy, Dall, Dall and Harris, Earle Sloan, and G. T. Pugh. J. A. Holmes, Tuomey, F. S. Holmes, and Dall have made important contributions to the knowledge of the invertebrate animals. For our knowledge of the vertebrates we are indebted principally to F. S. Holmes and Joseph Leidy. The author who has dealt most recently and in considerable detail with the stratigraphy of the Pleistocene deposits is Earle Sloan, State geologist (Bull. No. 2, ser. IV, South Carolina Geol. Surv., 1908, 479 pages). From these authorities we learn that, while the larger part of the Coastal Plain may be to a greater or less extent overlain by deposits referable to McGee’s Columbian, the deposits which bear fossils are confined almost wholly to a narrow strip along the coast. In this strip have been found the numerous mollusks listed and described by Tuomey, F. S. Holmes, and W. H. Dall, as well as most of the species of vertebrate fossils. The fossiliferous deposits do not usually extend back from the coast more than about 10 miles.

Undoubtedly fossil-bearing Pleistocene deposits are to be found here and there along all the rivers, perhaps to the western border of the Coastal Plain. This is indicated by the discovery of remains of horses and mastodons in Darlington and Richland counties. The thickness of the Pleistocene deposits along the coast is said to amount to as much as 60 feet, but it is usually much less. Only a part of this is fossiliferous, a bed that appears to vary in thickness from about 3 to 8 feet. This is found as much as 8 feet above mean-tide level, sometimes below it. The materials of this fossiliferous bed vary greatly. Sometimes they consist almost entirely of shells of mollusks, in other cases of a blue mud or sand, and with these may be mingled peaty materials, gravel, and again rolled masses derived from the underlying deposits. The fossils contained in the bed mentioned consist of mollusks, and in some places bones and teeth of vertebrates occur in more or less abundance. The bed is underlain often by deposits of Tertiary age. Bones and teeth of the vertebrates, as fishes and cetaceans, that lived when those Tertiary rocks were being deposited may occasionally have been washed into the Pleistocene bed. Again, where the older and the newer beds are exposed along the shores, fossils may be washed out of both and commingled on the beach; then again, a great part of the fossils collected along this coast of South Carolina have been rescued from the phosphate rock gathered for commercial purposes. This has been to a great extent dredged from the rivers; and thus remains of Pleistocene and of Tertiary animals have been mixed indiscriminately together. It is often impossible to determine to what formation a fossil may belong. To add to the difficulty of the palæontologist, the vertebrate remains are sometimes found washed out and mingled with bones or teeth of what appear to have been domestic animals.

Beginning at the northern end of the South Carolina coast-line, the first locality furnishing Pleistocene fossils is, or rather was (Pugh, op. cit. p. 33), White (or Price’s) Creek, in Horry County. Here at a height of about 5 feet above tide was found a bed approximately 6 feet thick apparently thrown up on the shore by storms (Tuomey, Geol. Rep., 1848, p. 187). No vertebrates have been reported from the locality. At Laurel Hill, in the extreme northeastern corner of Georgetown County, Tuomey (op. cit., pp. 187, 188) found a perpendicular bluff 30 feet high, at the base of which was a bed 8 feet thick made up of sand and broken shells. The top of the bed was 8 feet above tide, the highest elevation reached by the bed along the South Carolina coast. Tuomey mentions other localities around Georgetown where the fossiliferous bed was discovered. One was on Santee River. No vertebrates appear to have been met with in this region. In Christ Church parish, in Charleston County, Tuomey discovered several exposures of the bed in question, and this was sometimes so superficial as to be within reach of the plow.

Pugh (Pleistocene Deposits, etc., p. 34) quotes from F. S. Holmes a section which was found at Goose Creek, north of Charleston, as follows:

Yellow sand 12 feet
Blue mud 29 feet
Ferruginous sand, containing bones, etc. 3 inches
Yellow sand 3 feet
Pliocene marl resting on Eocene white marl 12 feet

The bones occurred likewise in the blue mud, and such were especially well preserved. Leidy (Holmes’s Post-Pl. Foss. S. C., p. 102) recounts his observations at this locality; nevertheless, the only vertebrate fossil that the writer finds credited by Leidy to this locality is a tooth of _Equus fraternus_ (=_E. leidyi_), which he figured (plate XV, fig. 8).

Dredging for phosphate rock has been carried on extensively in Cooper River; but of Pleistocene vertebrate fossils secured here the writer has record of only _Megatherium, mirabile_. This is represented in the Charleston Museum by a portion of a lower jaw.

Wando River is situated northeast of Charleston, runs parallel with the coast, and empties into Cooper River. From this have (according to the writer’s knowledge) been secured only _Equus complicatus_ and a part of a tusk of _Odobenus_. The latter is in the Charleston Museum. In most cases no record has been kept of the origin of the specimens in collections.

The Pleistocene bed along Ashley River is famous for the number of fossil vertebrates which it has furnished. It has been described by F. S. Holmes in various publications, especially in the Introduction to his Post-Pleiocene Fossils of South Carolina, 1860, pages I-XII. In the same work, on pages 99–100, Dr. Leidy briefly described the geological character of the beds; and on subsequent pages he described the vertebrate species found there. The principal beds were located on Ashley River, about 10 miles above Charleston. According to Pugh (“Pleistocene Deposits of South Carolina,” p. 34), the fossiliferous deposits rest on Miocene marls. At the top are 4 feet of yellow sands with bands of clay; below, is a foot or more of blue mud lying on the Miocene. The bones are more numerous and best preserved in the blue mud. The Pleistocene bed is elevated only a few feet above tide-level. Inasmuch as nearly all the species of Pleistocene vertebrates which have been found along the South Carolina coast have been secured along the Ashley River, the few found elsewhere will be included in the following list. Some of those marked found somewhere about Charleston may have been collected in or along Ashley River. In this list the contractions following the names signify as follows: A, Ashley River; B, the region about Beaufort; C, somewhere around Charleston; C. r., Cooper River; E, Edisto River; G. c., Goose Creek; J. i., John’s Island; S. r., Stone River; W. r., Wando River; Y., Yonge’s or Young Island. The species preceded by the dagger are extinct.

Odobenus rosmarus A., W. r. (p. 29). Lynx ruff us C. †Canis sp. indet. C. Procyon lotor A. †Arctodus pristinus A. Ursus americanus C. Sylvilagus floridanus? A. †Hydrochœrus æsopi A. †Hydrochœrus pinckneyi C. (p. 365). †Castoroides ohioensis A. (p. 279). Castor canadensis A. Ondatra zibethica A. †Elephas imperator C. (p. 162). †Elephas columbi A., B. (p. 155). †Mammut americanum A., B. (p. 118). Mammut progenium (p. 118). †Bison latifrons? A. (p. 260). †Bison sp. indet. A. (p. 260). †Alces runnymedensis C. (p. 364). Cervus canadensis A. (p. 242). Odocoileus virginianus? A. (p. 231). Camelops sp. indet. †Tagassu lenis A. (p. 222). †Tagassu sp. indet.? A. (p. 222). †Tapirus haysii A. (p. 204). †Tapirus sp. indet. A. (p. 205). †Equus complicatus A., W. r., B. (p. 192). †Equus leidyi A., J. i., G. c., S. r., B. (p. 192). †Equus littoralis C. (p. 193). †Hipparion venustum A. †Physeter vetus A. †Trichechus antiquus A. †Megatherium mirabile A., C. r., S. r. (p. 35). †Mylodon harlani A. (p. 35). †Megalonyx jeffersonii B. (p. 35). †Didelphis virginiana J. i. †Alligator mississippiensis A. †Pseudemys sp. indet. A. †Testudo crassiscutata? A. Trichiurus lepturus Y. †Istiophorus robustus Y. †Ischyrhiza mira? A. Lepisosteus osseus A. Dasyatis hastata? Y.

Besides the species enumerated, the early collectors found remains which were identified as belonging to such domestic animals as the dog, ox, sheep, and hog. Leidy rejected these as Pleistocene species, while Holmes and Agassiz accepted them as such. Possibly the supposed dog was in reality a wolf and the supposed ox a bison. Small teeth like those of cows are fossilized as are the teeth of extinct animals. At Bee’s Ferry on Ashley River the fossiliferous bed has a thickness of 3.5 feet and is at about high-water mark. It is overlain by from 15 to 20 feet of loose sands.

By far the most of the species have been entered in the list on the authority of Joseph Leidy. Only F. S. Holmes reported the elk (_Cervus canadensis_), and the writer has seen two teeth of the species at the Academy of Natural Sciences in Philadelphia credited to Charleston. Holmes also reported _Glyptodon_, but that is not included in the list. _Lynx ruffus_, _Ursus americanus_, _Hydrochœrus pinckneyi_, _Elephas imperator_, _Bison latifrons_, _Alces runnymedensis_, _Camelops_ sp., and _Equus littoralis_ are included on the evidence of specimens seen by the writer in the Charleston Museum or in some of the other collections made on the coast of South Carolina. Loomis has recently (Amer. Jour. Sci., vol. XLV, 1918, p. 438) described a specimen of _Mammut progenium_ (as _Mastodon americanus_) from near Charleston and another from near Beaufort.

_Alces runnymedensis_ was first briefly referred to in Year Book No. 14 of the Carnegie Institution of Washington, 1915 (1916), page 387. The name is based on an upper right hindermost milk molar in the Charleston Museum (No. 13534). It is the property of Mr. Charles C. Pinckney. Where the tooth was found is not known, but it was somewhere near Charleston, in the phosphate-bearing area. The specific name is that of the estate of the owner. The tooth closely resembles the corresponding one of _Alces americanus_, but is larger and has a flatter crown. Only the crown of the tooth is preserved, and of this a part of the enamel of the inner anterior cone is broken off; otherwise it is in fine condition. The color is very black. The following measurements are given of this tooth and of the corresponding one of _Alces americanus_, No. 117055 of the U. S. Biological Survey. The two teeth are only slightly worn.

_Measurements of milk molars of Alces, in millimeters._

┌────────────────────────────────────┬──────────────┬─────────────────┐ │ Dimensions taken. │A. americanum.│A. runnymedensis.│ ├────────────────────────────────────┼──────────────┼─────────────────┤ │Length of tooth near outer border │ 24.0│ 25.5│ │Length of tooth at middle width │ 21.5│ 23.0│ │Width of tooth along front border │ 23.0│ 23.0│ │Width of tooth from median style to │ │ │ │ base of inner hinder cone │ 21.0│ 24.0│ └────────────────────────────────────┴──────────────┴─────────────────┘

The angle between the outer and inner faces of the hinder half of the tooth is 54° in the tooth of the existing species, 64° in the fossil tooth. On the grinding-surface the fossettes are wider than in the tooth of the existing moose.

It is interesting to find this moose in the region about Charleston. We must suppose that it lived there during one of the glacial stages, probably when the walrus occupied that part of the coast.

In the Pinckney collection is a tooth of a capybara that deserves attention. A figure of it is here presented (fig. 18), a side view. Exactly where the tooth was found is not known, but it was somewhere in the vicinity of Charleston. The tooth is the upper left hindermost molar. In the figure the front end is directed toward the left hand. There are present 17 plates. None of the plates either in front or behind are missing. The free edges of the plates are not turned backward. The length of the tooth is 62 mm., the width is 17.5, the height of the plates on the inner face 37 mm., but probably the less calcified bases of the plates have been destroyed.

FIG. 18.—Side view of upper last molar of _Hydrochœrus pinckneyi_ from
Charleston, S. C. ×1. Type.
]

On the grinding-surface the plates run obliquely from the inside outward and backward. As seen on the inner face, the plates, as they pass to the grinding-surface, lean backward. The corresponding tooth of a capybara from Surinam has a length of 37 mm. The length of its skull from foramen magnum to the front of the snout is 215 mm. In case the skull of the fossil was long in proportion to the length of the tooth, the length as given above would be 360 mm., about 15 inches.

To this fine large species I give the name _Hydrochœrus pinckneyi_, in honor of Mr. Charles C. Pinckney, the owner of a collection of fossils from the region about Charleston and the proprietor of the estate of Runnymede, near Lambs, South Carolina.

In the same collection is a part of the lower jaw, right side, of a rather large wolf. In this jaw there remain the complete fourth premolar, the roots of the third premolar, and one root of the second (fig. 19).

The following measurements are taken from the fragment mentioned; from the corresponding part of a jaw of _Ænocyon dirus_, No. 8307, from La Brea, California; from the gray wolf, _Canis occidentalis_, from Fort Simpson, British America, No. 9001, U. S. National Museum; and from the type of _C. floridanus_, in the U. S. National Museum.

_Measurements of jaws and teeth of wolves, in millimeters._

┌───────────────────────┬──────────┬──────────┬────────────┬──────────┐ │ Parts measured. │ │ │ C. │ C. │ │ │Charleston│ La Brea │occidentalis│floridanus│ │ │ jaw. │ jaw. │ jaw. │ type. │ ├───────────────────────┼──────────┼──────────┼────────────┼──────────┤ │Height of jaw in front │ │ │ │ │ │ of pm_{4} │ 28│ 32│ 33│ 21.5│ │Thickness at front of │ │ │ │ │ │ pm_{4} │ 14│ 16│ 14.2│ 10.2│ │Length of pm_{4} │ 18.5│ 20.2│ 18.5│ 14.5│ │Thickness of hinder │ │ │ │ │ │ lobe of pm_{4} │ 9.5│ 11│ 9.5│ 7│ │Thickness of front lobe│ 8.5│ 9.8│ 8.5│ 6.4│ └───────────────────────┴──────────┴──────────┴────────────┴──────────┘

The measurements show that the fossil is much too large to belong to the wolf now inhabiting Florida. It appears also to be too small to belong to the wolf _Ænocyon dirus_, and _A. ayersi_ was but little if any smaller. The lower teeth of the latter species are not known. The accordance in measurements with those of _C. occidentalis_ makes it probable that the fossil jaw found at Charleston belonged to a wolf not greatly different. With the materials at hand it is impossible to refer the jaw specifically.

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.

Professor Earle Sloan, in his “Mineral Localities of South Carolina” (Bull. No. 2, ser. IV., South Carolina Geol. Surv.), has recognized the following divisions in the marine Pleistocene of the State:

6. Sea Island loams.

5. Wando clays and sands.

4. Accabee gravels.

3. Bohicket marl-sands.

2. Wadmalaw marl.

1. Ten-Mile sands.

Of these, the fossiliferous deposits referred to above appear to belong to the Wadmalaw marl. It may be confidently expected that somewhere along the South Carolina coast, beneath the beds bearing the vertebrate fossils, there will yet be discovered other Pleistocene deposits, probably shell marls, which belong to the Nebraska stage.

GEORGIA.

The only part of Georgia at present of interest to the student of vertebrate palæontology is that which lies immediately along the Atlantic coast and along a few of the larger rivers. The northwestern corner of the State is mountainous and probably contains little or no Pleistocene. The Coastal Plain extends landward to a line which starts at Augusta, on Savannah River, passes through Milledgeville and Macon, and ends at Columbus, on the Chattahoochee. A large part of this region is mantled by a deposit resulting from the decay of the underlying rocks. These deposits are of uncertain age, a part belonging probably to the Pleistocene, but the large part to the Pliocene or to still older Tertiary. The Pleistocene has not yet been differentiated from the remainder, and, in any case, has furnished no vertebrate fossils. For information on the subject the reader may consult McGee (12th Ann. Rep. U. S. Geol., Surv., pt. I, pp. 478–484), Spencer (Geol. Surv. Georgia, 1890–91, pp. 61–81), and Veatch and Stephenson (Bull. 26, Geol. Surv., Georgia, pp. 400–456).

The deposits in Georgia which can with certainty be referred to the Pleistocene form a broad belt lying along the coast and extending landward a distance of about 30 miles along Savannah River and about 60 miles at the Florida boundary line. For a description of these deposits the reader is referred to Veatch and Stephenson’s article in Bulletin 26 just mentioned, pages 424–456. These deposits are disposed in two terraces, a higher and older and a lower and younger. The older is named the Okefenokee formation, the younger the Satilla formation. The positions of these may be observed in the figure here presented, taken from Bulletin 26 above referred to (fig. 20).

The Okefenokee terrace has a breadth of 20 to 40 miles and an elevation of 60 to about 125 feet above sea-level. It forms a plain which Veatch and Stephenson describe as in general flat and almost featureless. It is dotted with cypress ponds and swamps, with here and there low ridges and hills of sand. Along the larger streams which cross the plain are found terraces supposed to have been laid down while the Okefenokee terrace was forming; they extend far back into the State. In neither the main terrace nor the fluviatile terraces have any fossils been found, except a little silicified wood.

FIG. 20.—The Coastal Plain of Georgia. Adapted from Veatch.
]

The Satilla Plain extends backward from the coast 20 to 30 miles and varies in elevation from 15 to 40 feet. On the landward side it ends in an escarpment which is taken, by the authors quoted, to be an old sea-beach. Along the large rivers it is continued as a series of terraces occupying a lower position than those of Okefenokee time. According to Veatch and Stephenson, this formation consists of unconsolidated clays, sands, and thin layers of gravel. The thickness averages about 15 feet, but may become as much as 45 or 50 feet.

The Satilla deposits are fossiliferous. At various places, at some distance from the coast, sea-shells occur, especially shells of oysters. This shows that at times the plain, or at least some parts of it, has been under sea-water. Bones and teeth of vertebrate animals have been discovered at several localities, but at only two places have identifiable materials been secured. The region about Brunswick and that just south of Savannah have furnished important collections of vertebrate animals.

During the years 1838 and 1839 an attempt was made to construct a canal to connect Altamaha River with Turtle River at Brunswick. Some bones of large mammals were met with and came to the notice of Hamilton Couper, and through him became known to the scientific world. The most striking was the great ground-sloth, of the genus _Megatherium_, and which Leidy afterwards called _Megatherium mirabile_. At a more recent time, during dredging operations, probably in the harbor, other remains were found and turned over to the Geological Survey of Georgia. The fragmentary bones and teeth were identified by Mr. J. W. Gidley (Bull. No. 26, Geol. Surv. Georgia, p. 436).

The fragments of teeth regarded by Gidley as belonging to _Mammut floridanum_ appear to the writer to represent _Gomphotherium rugosidens_, a species rather common in that region and belonging to the upper Miocene or Lower Pliocene. Four teeth identified as those of _Physeter vetus_ or _Physeterula neolassicus_ appear to be identical with Leidy’s _Orycterocetus quadratidens_; but this may be possibly the same as _Physeterula neolassicus_ (=_P. dubusi_). It, too, is older than the Pleistocene. From the two collections have been determined the following list:

Castoroides ohioensis (p. 280). Elephas columbi (p. 157). Mammut americanum (p. 120). Bison sp. indet. (p. 261). Cervus? sp. indet. (p. 243). Tapirus haysii (p. 206). Equus complicatus (p. 193). E. leidyi (p. 193). E. littoralis (p. 193). Megatherium mirabile (p. 36). Mylodon harlani (p. 36). Chelonia (??) couperi. Crocodylus (?) sp. indet. Lamna sp. indet. Galeocerdo sp. indet. Carcharodon sp. indet. Dasyatis sp. indet.

With the bones found in the canal was a femur 13 inches long, which Harlan described as _Chelonia couperi_, but which resembles more closely that of some edentate mammal. Gidley stated that the shark-teeth probably represent Eocene and Miocene species. This may be true, but the supposition is not necessary, inasmuch as species of all three genera are yet living on our Atlantic coast.

J. Hamilton Couper (Hodgson’s Memoir, pp. 37–40) has given an account of the topography and geology of the region through which the Brunswick Canal was being constructed (map 40). On one of the plates of the work is a section from the ocean westward 21 miles. About 10 miles west of St. Simon’s Island the canal passed through Six-mile Swamp. This is connected at its northern end with Altamaha River, at the southern with Turtle River. The swamp has thus the appearance of a lake which has become filled with alluvial deposits. These consist of a compact clay, usually yellow and impregnated with iron. There are thin strata of soft, chalky marl and many fragments of petrified wood. At the bottom of this deposit were found the bones of _Megatherium_, _Elephas_, _Mammut_, _Equus_, and _Bison_. Beneath the clay stratum was sand with marine shells. Overlying the clay was a thin stratum of vegetable and sandy loam. The bones occurred at a depth of from 4 to 6 feet. In no instance, except when they had been washed out into the salt-water creek, was there any abrasion of the surface or incrustation of marine shells.

The geologist Charles Lyell (Second Visit, etc., vol. I, p. 347) stated that part of a skeleton of a megatherium, dug out in cutting the canal, was so near the surface that it was penetrated by the roots of a pine tree. As a considerable number of the bones of one skeleton were found together, Lyell supposed that a whole carcass had been floated down the river to the spot.

Even before remains of fossil vertebrates had been found at Brunswick, bones had been discovered at Skidaway Island, near Savannah. As early as 1823, S. L. Mitchill (Ann. N. Y. Lyc. Nat. Hist., vol. I, p. 58) announced the finding of teeth of _Megatherium_ at this place. More than 20 bones of the same animal were reported from the same locality in 1824 by William Couper. In 1846 (Hodgson’s “Memoir on Megatherium,” pp. 25–30), Dr. Joseph Habersham published a list of the species discovered up to that time. Lyell (Second Visit, etc., vol. I, p. 313) gave an account of his visit to the locality and noted the species obtained. The following list appears to contain all found there:

Elephas columbi (p. 157). Mammut americanum (p. 120). Bison sp. indet. (p. 262). Equus leidyi? (p. 194). Megatherium mirabile (p. 36). Mylodon harlani (p. 37). Terrapene canaliculata.

The box-tortoise _Terrapene canaliculata_ was described by the writer in 1907 (Bull. Amer. Mus. Nat. Hist., vol. XXIII, p. 850, figs. 5–7) on fragmentary materials found in the U. S. National Museum. These had been sent there by Dr. J. P. Scriven, who had been active in collecting the fossil vertebrates about Savannah. Whether the remains of this box-tortoise were found on Skidaway Island or in Whitemarsh Island is uncertain.

Besides these species, found on Skidaway island, two species, _Mammut americanum_ and _Mylodon harlani_, have been found at Heyner’s (or Hainer’s) Bridge. This is about 7 miles south of Savannah, where the road crosses Vernon Creek (Lyell, “Travels in North America,” vol I, pp. 163–164). Here the stream is called White Bluff Creek. In order that the reader may get a clear understanding of the conditions at this important locality, a map found in Hodgson’s Memoir is reproduced (map 40).

The whole region south of Savannah, between the mouths of Savannah and Ogeechee Rivers, is low and much divided into islands by streams connected with the rivers mentioned. A considerable part of these islands consists of marshes, which are usually overflowed by the tides. Most of the fossil bones were found along the southern bank of Skidaway River, in two places, apparently about 0.5 mile apart and near the western end of the island. On the map Hodgson has named the locality Fossilossa. Here Skidaway River made a bend which caused the bank to be eroded away, thus exposing the bones. According to Couper (Hodgson’s Memoir, p. 40), the bones were embedded in the marsh formation at about the level of very low-water. Lyell (Second Visit, etc., vol. I, p. 314) stated that the bones occurred in a dark peaty soil, or marsh mud, above which was a stratum of sand 3 or 4 feet thick; while below the peaty soil and below sea-level was sand containing many marine fossil shells, all belonging to species yet living on the neighboring coast.

The authors quoted state that at various places along the Georgia coast are found stumps of trees, cypress, cedar, and pine, in the deposits of the salt marshes and at a depth of from 2 to 4 feet below high-water. This is taken as evidence of subsidence in that region.

It is a matter of importance to know how those animal remains reached their place of burial. It has been suggested that whole carcasses had been floated down the streams and sunken where the bones are found. This is possible, but not probable. The peaty nature of the deposit inclosing the bones appears to be opposed to this view; nor could disarticulated bones have been washed down far from above, for they show no signs of attrition. The most probable explanation is that these animals lived and died about where their bones were discovered. At some past time the surface stood at a higher level than at present, although low enough to be more or less marshy. It probably supported a dense forest growth, and hither the species listed above resorted, with many others not yet discovered.

The animals inhabiting the region represent the same fauna found at so many places in Florida and Texas. The writer believes that they existed during the early part of the Pleistocene, approximately during the Aftonian interglacial; and that some of the species, as _Megatherium_, _Mylodon_, _Equus_, and _Tapirus haysii_ became extinct before the advent of the Wisconsin glacial stage, probably a long time before this.

FLORIDA.

(Maps 7, 8, 15.)

For the most recent descriptions of the geology of Florida one must consult the Annual Reports of the Florida Geological Survey, issued by the State geologist, Dr. E. H. Sellards, and Water supply Paper 319 of the U. S. Geological Survey, prepared by George C. Matson and Samuel Sanford and published in 1913. In the latter work are two large maps, one representing the topography of the State and the distribution of the various geologic formations; the other presents a generalized view of the distribution of Pleistocene terraces, as recognized by Matson and Sanford. The Second Annual Report of the Florida Geological Survey contains a map similar to the first mentioned.