Fig. 15.—Diagram showing the ideal arrangement of the supposed terraces in the Maryland Coastal Plain. From Shattuck.
The Lafayette is regarded as having been laid down during the Pliocene. The Sunderland, Wicomico, and Talbot form three terraces, of which the Sunderland is the oldest, most elevated, and farthest away from the larger bodies of water. It is composed of clay, peat, gravel, and boulders supposed to have been brought in by the ice. The coarser materials appear to occupy usually the lower parts of the formation. The elevation near Washington is about 200 feet, but southward it descends gently, until in St. Mary’s County it is only about 60 feet. The thickness varies from about 80 feet to nothing. According to Shattuck, at the time of deposition of the Sunderland the coast was depressed to an extent of about 200 feet, so that its materials were laid down either in salt water or in that of wide estuaries. No deposits belonging to it have been found in the eastern peninsula. In the western peninsula considerable areas are recognized along the Potomac up to Washington and along the Patuxent and Chesapeake Bay to Baltimore and Elkton. Except in the southern part of this peninsula, the Sunderland is found only in widely separated patches. No marine organisms are known to have left their remains in the Sunderland, but forest trees of a number of existing genera and several extinct species have been described by Hollick in the volume cited.
The Wicomico formation is described as occupying a large portion of the central and higher parts of the eastern peninsula; in the western it forms a narrow and often interrupted fringe around the Sunderland. North of Washington and Annapolis it occurs only in patches. Its materials are very similar to those of the Sunderland. Its greatest elevation is about 100 feet above sea-level, and this, according to Shattuck’s view, marks the amount of depression of the land at that time. The thickness may be as much as 70 feet, but is usually much less. No marine fossils proper to the period have been discovered in the deposits, but at a point in Prince George’s County plant remains have been found in a deposit about 20 feet thick.
The Talbot formation forms a fringe, sometimes of great width, sometimes narrow or interrupted, along all the large bodies of water in this State and in Delaware. It is the lowest of the terraces. The greatest elevation is about 45 feet; the thickness does not exceed 40 feet. The materials noted are those of the other two formations—clay, peat, sand, gravel, and ice-borne boulders. At several points along Chesapeake Bay and on the lower part of Patuxent and Potomac rivers, deposits containing plant remains have been discovered, including pines, cypress, hickory, beech, elm, and black locust. In contrast with the other formations, the Talbot has furnished many marine fossils, mostly mollusks; but in all cases the localities are close to the present coast.
The writer does not accept the theory that the materials forming what have been called the Sunderland, Wicomico, and Talbot terraces have been to any great extent laid down in the sea. Some part of the Talbot, that lying near the present coast, has undoubtedly had such an origin. Nor has the Coastal Plain suffered, so far as is determinable, any such amount of depression as the theory mentioned requires. The materials of the Sunderland and Wicomico have, in the writer’s opinion, been brought down by rivers whose beds lay at levels nearly as high as those of the real or supposed terraces. When the Talbot materials were laid down, the rivers and estuaries of the coast had been cut down nearly to their present levels, and this was not long after the beginning of the Pleistocene.
The authors of the submergence theory admit that no satisfactory evidence of the presence of marine organisms, vertebrate or invertebrate, are to be found in the body of the assumed terraces, except again in parts of the Talbot which immediately border the ocean or the great estuaries. It is almost inconceivable that the ocean could occupy the Coastal Plain from New Jersey to Mexico for thousands of years and lay down great thicknesses of clay, sand, and gravel without having left somewhere beds of molluscan shells in such situations that they would have been discovered. While these marine fossils are lacking, there are found on all these terraces from Maryland to Florida and to the Rio Grande an abundance of land vertebrates such as elephants, mastodons, horses, camels, peccaries, and many other forms. Nor do our palæobotanists have difficulty in finding oaks, walnuts, hickories, poplars, etc. On the theory of submergence there are missing all the things that ought to be found and there are met with just the things that would not be expected.
A figure is here reproduced (fig. 15) from the Maryland Pliocene and Pleistocene volume, page 66, with the explanation there accompanying it. The reader may judge for himself whether the sea could occupy the Atlantic coast since Pliocene times without leaving any traces of marine fossils, while at the same time there were preserved in those terraces remains of land animals and land vegetation.
Another section (fig. 16) is reproduced from Folio 179 of the U. S. Geological Survey, the authors of which are G. W. Stose and C. K. Swartz. The uppermost terraces are by these authors supposed to belong to the late Pliocene, the formation formerly known as the Lafayette. These figures suggest that the one set of terraces have some connections with the other set.
Fig. 16.—Section across Potomac River near Big Pool, Maryland. Shows gravel-covered terraces. Folio 179, U. S. Geol. Survey.
Beginning at the southern extremity of Maryland, we notice the occurrence of remains of Mammut americanum at or near St. Mary’s City. Other remains of the same animal have been secured near St. Clements in St. Mary’s County (p. 112). Both of the localities are situated on territory mapped by Shattuck as Wicomico; but as remarked on page 112, our knowledge of the conditions under which the fossils were found is not sufficient to allow us to say more than that they belong to the Pleistocene. The species existed from early to late Pleistocene and can not be used to determine the age of the deposits.
Along Patuxent River, in Charles County, not far from Benedict, Cope (Proc. Acad. Nat. Sci. Phila., 1867, p. 155) recognized jaws and teeth of Grison macrodon and of Tagassu lenis (p. 220). Both are extinct species.
According to Shattuck’s map of 1906, this region is covered by the Talbot formation; but inasmuch as the species named were obtained from pits furnishing Miocene marl, one can not be sure that they are not older than the supposed Talbot. It would probably require a search in the land records in order to determine exactly where the objects were found. The presence of Elephas primigenius suggests that this animal had been pushed down here during one of the glacial stages.
Nearly a hundred years ago an elephant tooth (p. 154) was found somewhere in Queen Anne County, but it would probably be now impossible to determine the locality. In case the elephant tooth was found near Chesapeake Bay, as is very probable, there is no record of any Pleistocene vertebrate having been found in the central and eastern parts of the eastern peninsula.
In the eastern peninsula remains of Pleistocene vertebrates have been recorded from only two localities, Oxford Neck, Talbot County, and an undetermined locality in Queen Anne County. From Oxford Neck, Cope (Proc. Amer. Philos. Soc., vol. XI, 1869, p. 178) reported Elephas primigenius, E. columbi, Cervus canadensis, Odocoileus virginianus, Chelydra serpentina, and Terrapene eurypygia.
At Chesapeake Beach, William Palmer, of the U. S. National Museum, discovered a few remains of Pleistocene vertebrates. One of these is a tooth of an undetermined species of Bison, probably not the existing one. Another species is probably Equus leidyi (p. 189). Three teeth appear to represent the peccary Tagassu lenis (p. 220). In 1921, Dr. Adolph H. Schultz, of the Johns Hopkins Medical School, presented to the U. S. National Museum another specimen of T. lenis which he had found at Chesapeake Beach. Inasmuch as the fossils were picked up after having fallen from their resting-place, it is impossible to say to which formation they belonged. In the opinion of the writer, none of the three species indicates a late Pleistocene time.
On the opposite side of the western peninsula, at Marshall Hall, Charles County, there was found long ago a tooth which the writer refers to Equus leidyi.
Coming north into the District of Columbia, we find recorded the discovery of remains of horses and possibly at two different times. According to Darton’s work (Folio 70, U. S. Geol. Surv.), there is some later Columbia laid down along the route of the Chesapeake and Potomac Canal above Georgetown. This would now doubtless be regarded as belonging to the Talbot. It seems to follow that either the Talbot is much older than has been supposed or that some of the extinct horses continued on until a comparatively late time in the Pleistocene.
Within the limits of the city of Washington there has been found a tooth of probably Elephas primigenius at a depth of 35 feet, in the Wicomico formation (see p. 178). On any theory of the origin of the terraces, the presence of the tooth at that depth in the ground and at that elevation appears to indicate a considerable geological age for the animal. To what extent materials may have been washed down from the surrounding higher land may be difficult to determine.
In Prince George County, near Mitchellville, have been found two teeth of an extinct horse (p. 188). These are as yet unidentified. They are in the U. S. National Museum, No. 8813.
Near Towson, in Baltimore County, a mastodon tooth has been found (p. 112); but beyond proving that there is at that locality some Pleistocene deposit, it gives us little information.
In 1920 (Proc. U. S. Nat. Mus., vol. LVIII, pp. 96–109), the writer described a collection of vertebrate fossils, collected in a cave or fissure in limestone at Cavetown, Washington County, by anthropologists from Phillips Academy, Andover, Massachusetts. The following is the list of species that were found in the collection:
Of the 22 species here recognized 12 are extinct. This large number of itself indicates that their time of existence was not recent. Similarly, the presence of 2 species of horses, several species of peccaries, and of a saber-tooth tiger points to a rather ancient period. The writer believes that the assemblage belongs to the Sangamon stage of the Pleistocene.
Fig. 17.—Generalized section across the Allegheny Valley at Parkers Landing, West Virginia, showing various stages of erosion and valley fill. U. S. Geol. Surv. Folio 178.
In Washington County, probably along Lane’s Creek, was found, in digging a mill-race, the skull of a mastodon (p. 112). Further east, near Clear Spring, and about a mile above the entrance of Conococheague Creek into the Potomac, was discovered a tooth of a mastodon (p. 113). This had been washed out of some deposit along this creek, probably not far away from where it was found. As Stose has shown (Hancock Folio, No. 179, U. S. Geol. Surv.), along the Potomac and its tributary streams there are extensive Pleistocene deposits of sand and gravel, laid down when the river was as much as 200 feet above its present level. It is probable that such deposits date from the early Pleistocene (fig. 17). A more important locality for Pleistocene vertebrates is that near Corriganville, about 3 miles west of north of Cumberland, Maryland. The cave is in Allegany County, west of Wills Creek and south of Jennings Run, about 0.5 mile south of the village of Corriganville. An account of this locality, with a list of the species determined up to that time, has been published by Gidley (Proc. U. S. Nat. Mus., vol. XLVI, 1913, pp. 93–102). In cutting through a spur of limestone in making a railroad, at a depth of about 100 feet there was exposed a cave or fissure which contained many bones and teeth. Gidley secured some hundreds of specimens belonging to about 35 species. Unfortunately nothing has been published which shows the relation of this cave to the terraces which are found along Potomac River and its tributaries. Through the kind offices of Mr. F. S. Rowe, welfare agent of the Western Maryland Railway, the writer has received from the division engineer, Mr. P. Cain, of Cumberland, a topographic map of Allegany County and a profile of the road extending through the rock cut. From these it appears that the level of the track, at the fissure, is 837 feet above sea-level. This seems, therefore, to be considerably above the highest terrace along the Potomac in that region. It is to be supposed that the fissure was formed long before the animal remains accumulated in it.
In a paper published in 1920 (Proc. U. S. Nat. Mus., vol. LVII, pp. 651–678, plates LIV, LV, text-figs. 1–10) Gidley added to his former list four species of peccaries, as follows: Platygonus cumberlandensis, P. intermedius, Mylohyus exortivus (all new), and M. pennsylvanicus. In another communication he reported also a deer, a wolverine, a beaver, a lynx, a badger, a marten, an eland, and a crocodile or an alligator (Rep. Smithson. Inst. for 1918, pp. 281–287). Many of the identifications are merely provisional.
On account of the present unstudied condition of the collection, it is difficult to reach conclusions that are satisfactory. It appears, however, that there are at least 6 hitherto undescribed species, one-fifth of the whole number. Another 6, if at all correctly determined, indicate a wide removal from their ranges of the present day. Lepus americanus now lives well toward the north, coming down to Saginaw, Michigan. Ochotona princeps lives in the Rocky Mountains of British America. Synaptomys borealis is known only from the region about Great Bear Lake, Mackenzie, Canada. Microtus chrotorrhinus has its habitat in Quebec and the northeastern United States. The species of Napæozapus are Canadian in their range, but descend to southeastern Maryland and to North Carolina in the mountains. Sciuropterus alpinus is found from Alaska to Hudson Bay, but descends on the Pacific coast to southern California. This northern habitat of so many supposed species suggests that the fissure received its contents during one of the glacial stages, and this may be the case. However, it is not unlikely that these species and some others are really undescribed ones. One may reasonably expect to find in a fauna containing Equus and Tapirus a much higher percentage of extinct species than Gidley has recorded.
The most remarkable member of the fauna is Taurotragus americanus, a species closely related to the eland of southern Africa (Gidley, Smiths. Misc. Coll., vol. LX, No. 27). Its presence in western Maryland gives a vivid impression of the widely extended journey that some animals have made from one continent to others. The same species has since been found in collections made at Alton, Illinois (p. 339), and at Kimmswick, Missouri (Proc. U. S. Nat. Mus., vol. LVIII, p. 113).
According to the author’s views, the fauna found at Cumberland, like that of localities in western Virginia, belongs to a time somewhere about the middle of the Pleistocene. Most of the species may be supposed to have lived there during the warm Sangamon stage; others, as the wolverine, at a somewhat earlier or later time when the climate was cooler.
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.
So far as the writer has learned, vertebrate remains belonging to the Pleistocene have been found in West Virginia in only eight places and only seven species are represented: Mammut americanum (p. 115), Elephas sp. indet. (p. 179), Equus niobrarensis? (p. 190), Symbos cavifrons (p. 254), Megalonyx jeffersonii (p. 34), Odocoileus virginianus? (p. 231), and a peccary (p. 221). The horse appears to indicate an early Pleistocene time, possibly pre-Kansan, but all the other species continued from at least the Aftonian stage through to the Late Wisconsin. The specimens, therefore, do not help us to determine the age of the deposits in which they are found.
No part of the State lies within the glaciated area; hence, during the whole of the Pleistocene epoch its surface was subjected to weathering and to the erosion of running water. At times the streams built up deposits on their beds. Later they deepened their channels and left a part of their former deposits as terraces. At a still later time the deposition and deepening may have been repeated, and as a result there is sometimes a series of terraces one above another. The age of these terraces and their origin have been the subjects of a good deal of controversy.
In the Masontown-Uniontown Folio (U. S. Geol. Surv. No. 82), M. R. Campbell has discussed the terraces along the Monongahela River, which occur at an altitude of about 1,000 feet above sea-level and perhaps 150 feet above the present river. Also more than 100 feet above the present river are old abandoned river channels which are now partially filled up.
In 1911 (U. S. Geol. Surv. Folio 178, pp. 11–13), E. W. Shaw and M. J. Munn described the Quaternary of the Foxburg and Clarion quadrangles in Pennsylvania, where the same Pleistocene problems are involved. They present an account of the different views regarding the high-level terraces and the abandoned channels. They concluded, as did Campbell, that these terraces and channels dated back to the early Pleistocene and probably to the Kansan stage. Figure 17 is a reproduction of Shaw and Munn’s figure 10, on their page 12. It represents a section across Allegheny River at Parker’s Landing, Armstrong County, Pennsylvania. The uppermost gravels in the figure would be those of supposed Kansan age; while the lowermost are those laid down during the last glacial stage, the Wisconsin. In the materials of the high terraces one may expect to find fossil vertebrates of the early Pleistocene, as in the case of the mastodon reported from Stewartstown, West Virginia (p. 116). The conditions of burial should, however, be carefully studied and recorded; for it would be possible for remains to be left at a later time on such a terrace and to be covered up by earth washed down from above.
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).
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.
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.