The Pleistocene of North America / and its vertebrated animals from the states east of the Mississippi River and from the Canadian provinces east of longitude 95°

by Oliver Perry Hay

NEW ENGLAND.

Inasmuch as relatively few vertebrates belonging to the Pleistocene have been discovered in the New England States, it will not be necessary to enter into details regarding the geology of the glacial period in this region. Nevertheless, the subject is one of great interest and one which has engaged the attention of many geologists. For those who wish to enter on the study, the writer recommends first a paper written in 1906 (Bull. Geol. Soc. Amer., vol. XVIII, pp. 505–556) by Frederick G. Clapp, entitled “Complexity of the Glacial Period in Northeastern New England,” which gives a brief history of the development of the idea that in the region mentioned there are evidences of more than one glacial and of more than one interglacial stage. There are also citations of the principal papers written on the subject. Among the writers cited are Shaler, Woodworth, Fuller, Upham, Stone, and Tarr. Clapp concluded that New England had been invaded by at least three ice-sheets and that these invasions had been separated by two interglacial intervals of long duration. On account of the greater thickness of the drift and because of fewer favorable exposures, due to the rocky nature of the coast and other causes, many difficulties are encountered in studying the deposits. He regarded absolute correlations as not yet possible. The last glaciation he accepted as corresponding closely with the Wisconsin, as displayed in States further west. What is known as Montauk drift, forming a part of the Gay Head interval of Woodworth, appeared to Clapp to correspond possibly to the Illinoian. Still older drifts would seem to have their place nearer the pre-Kansan (Nebraskan) than to the Kansan. What have been called “Leda clays” are found from Boston north into the St. Lawrence Valley. Clapp divides them into the “high-level” and the “low-level” clays. The former are the older and regarded as being about the equivalent to the Iowan stage. The “low-level clays” are referred to the Wisconsin stage. Another body of clays named by Fuller (Bull. Geol. Soc. Amer., vol. XVI, p. 375) the Gardiner clays, from their type locality, Gardiner Island, near the east end of Long Island, lies beneath the Montauk till and has been referred by Fuller to the Yarmouth interglacial.

In his paper cited Clapp presents (pp. 520–523) a list of the fossils, mostly mollusks, which have been collected in the Pleistocene deposits from New Brunswick to New York.

Along the New England coast are evidences of uplift which followed the retirement of the Wisconsin ice. Katz (Jour. Washington Acad. Sci., vol. VIII, 1918, p. 410) reported elevations of 155 feet at Stratham, New Hampshire, and 300 feet at Pawnal, Maine. Fairchild (Bull. Geol. Soc. Amer., vol. XXIX, p. 214) records the elevations at various localities in Maine.

A brief interesting account of the Pleistocene epoch as recorded in Massachusetts and Rhode Island may be found in an article by B. K. Emerson (Bull. U. S. Geol. Surv., No. 597, pp. 134–149). It deals in part with the geology of the valley of the Connecticut River.

Goldthwait (Appalachia, vol. XIII, pp. 1–23) and Foshay (Amer. Jour. Sci., ser. 4, vol. XXXVIII, pp. 345–348) have found evidences of an early Pleistocene glaciation in the White Mountains of New Hampshire.

Vermont is interesting especially on account of the Pleistocene history of Lake Champlain. This history has been recently discussed by Professor H. L. Fairchild (Rep. State Geologist Vermont, vol. X, 1916, pp. 1–41, with maps and views), who presents (pp. 40–411) a list, 37 in number, of the more important papers relating to the subject.

While the Wisconsin ice-sheet was resting upon Canada and the northern part of the United States, the land thus occupied, and probably a considerable area beyond the ice, became depressed. The valleys of the St. Lawrence, the Ottawa, the Hudson, and the Connecticut had been pressed down to such an extent that, as the ice-sheet retired these valleys became filled with water standing at sea-level. When at length the glacial front had retreated beyond the St. Lawrence, sea-water entered Lake Ontario and passed up Ottawa River far above the city of Ottawa (Leverett, Monogr. U. S. Geol. Surv., LIII, plate XXI). South of the St. Lawrence, marine waters occupied what is now Lake Champlain and as much of the surrounding land as was then at or below sea-level. In his account Fairchild makes use of the plate which is here reproduced (map [31]) from his article of 1917 (Bull. Geol. Soc. Amer., vol. XXVIII, p. 279, plate XI). This geologist believes that the Hudson formed for a while a connection with Lake Champlain, although the Hudson waters may not have been actually saline. But in Lake Champlain the presence of fossil marine mollusks and at least one whale skeleton shows that its waters were salt. The lines crossing the plate obliquely are the isobases which show the amount of elevation which has taken place along those lines since the end of the Pleistocene. South of New York City this is zero. At the northern end of Lake Champlain the elevation is 800 feet. This means that the north end of the lake for a while stood 800 feet lower than now. Marine fossils have, however, been found at an elevation of only about 300 feet. The waters which first occupied the lake and stood at the highest level were of glacial origin and fresh. When the ice-front had receded so as to open the St. Lawrence and admit sea-water, the northern end of the lake had been uplifted about 500 feet. It was then that the marine animals entered.

Other important papers to be consulted in this connection are as follows: One by J. B. Woodworth (Bull. 84 New York State Mus.); one by Charles E. Peet (Jour. Geol., vol. XII, 1904, pp. 415–469; 617–660), and two by Professor Fairchild (Bulls. 105, 127, New York State Mus.).

It is proper to say that certain glacial geologists maintain that the depression in the New England States has been less than supposed by Fairchild, and that the isobases curved around toward the north as the New England coast was approached, somewhat as represented by Taylor (Monogr. LIII, U. S. Geol. Surv., p. 503). Fairchild, in a later paper (Bull. Geol. Soc. Amer., vol. XXIX, 1918, pp. 187–244), has reached the same conclusion and presented a map on which are drawn the isobases, or lines passing through points affected by the same amount of post-glacial uplift; from this map [32] has been prepared. On his map the location of the heavy or solid lines is regarded by Fairchild as being based on clear evidence. Where the lines become thin the evidence is less trustworthy; where the lines are broken their positions are hypothetical. The numerals on the lines show the amount of uplift along those lines. Two points of importance are brought out on the map. The first is that Newfoundland formed an independent center of glaciation and of subsequent uplift, a conclusion based on good geological evidence. The second point is that the center of the Wisconsin glaciation was located southeast of James Bay, considerably farther south and west than is usually supposed. The confirmation of this is left to the future.

It does not seem to have been demonstrated that there are in Connecticut any Pleistocene deposits older than those laid down by the Wisconsin ice-sheet. In case Fuller (U. S. Geol. Surv. Prof. Paper 82) is correct in his determination of beds of the early, middle, and late Pleistocene on Long Island, it is to be expected that beds of corresponding ages will yet be recognized in Connecticut. Woodworth (17th Ann. Rep. U. S. Geol. Surv., pt. 1, p. 978) mentions deposits of clay at Berlin and at New Haven that may be older than the Wisconsin.

While the correlations recorded above of the Pleistocene of the New England States with the glacial and interglacial stages of the Mississippi Valley may be subject to modifications, it is interesting to learn that the presence of Middle and Early Pleistocene deposits in the Eastern States has received the recognition of so many students of glacial geology. The hope is awakened that in New England there may yet be found interglacial deposits which will furnish remains of Pleistocene vertebrates, as these have come to light from Throg’s Neck, New York, to southern Florida. It is possible that the astragalus of an equine animal (p. [183]), found at Gay Head, Martha’s Vineyard, belongs to a species of Equus of early Pleistocene age.

In order to illustrate still further the events connected with the history of the Pleistocene in the region of the Great Lakes, three additional figures are introduced. One of these (map [33]) shows J. W. Spencer’s conception of the drainage of the region in preglacial times. The areas now occupied by the lakes were then traversed by rivers. It will be observed that the rivers above Pittsburgh now discharging into the Ohio then emptied northward into the Erigan. This is shown also by a map (fig. 6) taken from Leverett (U. S. Geol. Surv. Monogr. XLI, p. 89). Figure [5], on page [287], shows the position of the shore of this Champlain Sea.

The number of Pleistocene vertebrates found in the New England States is limited, and most of them have been mentioned.

Somewhere on the coast of Maine have been found specimens of the fish Mallotus villosus (Gould, Proc. Bost. Soc. Nat. Hist., vol. III, 1848, p. 67). At Charlotte, Vermont, a white whale, Delphinapterus vermontanus, was found many years ago (p. [19]). Some bovid teeth were found many years ago at Gardiner, Maine, and referred to Bison bison, but it is now believed that they are teeth of the domestic ox. However, Dr. G. M. Allen has reported from Cape Cod, Massachusetts, teeth of a young bison (p. [266]). At Woodbury, Washington County, Vermont, at a depth of 7 feet, an antler and a piece of the upper jaw with five molars of Rangifer caribou (p. [244]) have been discovered (Rep. Geol. Surv. Vermont, vol VI, p. 7). Mastodons have been discovered in Massachusetts at Coleraine and Shrewsbury (p. [47]). Many years ago a tooth and a tusk and some bones of an elephant were found at Mount Holly, Vermont (p. [148]); the writer refers the animal to Elephas columbi. An undetermined elephant has been found in Vermont at Richmond (p. [167]). Walrus remains have been recovered at Addison Point (p. [23]), Andrews Island (p. [23]), Gardiner (p. [23]), and Portland (p. [24]), all in Maine; off Portsmouth, New Hampshire (p. [25]); and on Martha’s Vineyard, Massachusetts (p. [25]). At the latter place a tooth supposed to belong to the hooded seal (p. [26]) was found long ago. With respect to the specimens found at this place there is some doubt as to their geological age. With the exception that the reindeer bones (p. [244]) found near New Haven may be of pre-Wisconsin age, no Pleistocene vertebrate fossils older than Late Wisconsin appear to have been discovered anywhere in Connecticut. As shown elsewhere (p. [48]), there were found long ago at Sharon, Litchfield County, remains which were identified as those of mammoth, but these have since been regarded as those of the common mastodon. Only a single vertebra was preserved.

Fig. 6.—Probable preglacial drainage of the Upper Ohio. From Leverett.

Mastodons have been found in four other places, Cheshire, New Britain, Bristol, and Farmington (pp. 47, 48). The animals which left their bones at those places certainly lived after the last glacial sheet had withdrawn from the State. As mentioned on page [291], Fairchild has found reasons for believing that, while the Wisconsin ice-sheet was withdrawing from the Hudson and Connecticut Valleys, the whole region was so depressed that these valleys became occupied by water at sea-level. In these waters there were laid down thick deposits which now stand at levels much above tide, varying, in Connecticut, from nearly 200 to about 300 feet. Map [31], reproduced from Professor Fairchild (Bull. Geol. Soc. Amer., vol XXVIII, 1917, plate XI) is intended to show how wide an extent of territory along the Connecticut Valley was then submerged. It is probable that the emergence of these deposits was not accomplished until after the glacier had retired beyond the State.

It will be observed (map [6]) that the localities just mentioned, where the mastodons have been found, lie very close to or on the areas covered by the deposits mentioned. The pond in which the Farmington mastodon (fig. 6, No. 3) was buried is in a range of hills which must have stood as an island in the Connecticut inlet. While it is possible that mastodons lived on this island while the land was depressed, it is more likely that they lived there after it had been more or less elevated. Judging from the topographical maps, one may conclude that the mastodons that have been found at Cheshire (fig. 6, No. 1) and New Britain (fig. 6, No. 2) were buried in deposits that overlie those laid down at sea-level. Their time of existence must have been near the end of the Pleistocene. Too little is known about the mastodons reported from Bristol and Sharon to form any definite opinion about the stage of the Pleistocene when they lived; but it was probably after the withdrawal of the last ice-sheet.