NEW YORK.

From the geologist’s point of view there is hardly, if at all, another State which presents for solution more numerous or more interesting problems connected with the Pleistocene than does New York. Among these are the geography and topography of the State at the beginning of the Pleistocene; the number and identity of the glacial stages which affected its surface; the origin and development of the bordering Great Lakes, of the numerous interior lakes, and of the river courses, actual and abandoned. For a knowledge of these one must consult the various reports issued by the Geological Survey of the State; above all, the numerous and instructive papers that have been published by Professor H. L. Fairchild, of the University of Rochester.

For the student of Pleistocene vertebrate palæontology, the State of New York is not so attractive as some others; but it is far from being devoid of interest. Few species of vertebrates of Pleistocene age have been found in its deposits, and these, with one exception, belong to the latest episodes of the last glacial stage. So far as the writer is aware, the following list comprises all of the Pleistocene vertebrates known to have been found within the borders of the State; those marked with an asterisk (*) are now extinct:

Deposits of materials belonging to Pleistocene stages older than the Wisconsin are apparently of rare occurrence in the State. If existing they are usually concealed beneath the widely spread Wisconsin drift. On Long Island, Fuller (U. S. Geol. Surv. Prof. Paper 82) has described beds of gravels, sands, and clays, which he regards as belonging to the Nebraskan, Aftonian, Yarmouth, and Illinoian. None of these has furnished any vertebrate fossils. However, in 1866 (Smithson. Contrib. Knowl., vol. XV, art. 3, p. 16), Whittlesey reported that he had a tooth of a horse (p. [183]) found at Fort Schuyler, Throg’s Neck, 18 feet below the surface. This must have been lying beneath the Wisconsin drift. Inasmuch as Fuller has found the Manhassett formation, regarded as equivalent to the Illinoian, around Manhassett Bay, within 4 or 5 miles of Throg’s Neck, it seems entirely reasonable to suppose that deposits of similar or earlier age exist at Throg’s Neck.

With the exception of small areas, the whole of the State was at one time covered by the ice-sheet of the Wisconsin stage. The glacial ice filled the basins of the Great Lakes, and overrode even the peaks of the Adirondack and Catskill Mountains. Only along the southern side of Long Island and in the loop formed in Cattaraugus County by Allegheny River does the ice-sheet appear to have been absent.

Nearly everywhere, even on the southern coast of Long Island as outwash, it left its burden of clay, sand, gravel and boulders, usually many feet in thickness; in the mountainous regions this drift material is present, at least in the valleys. At the extreme southern edge of the glacial sheet there was laid down the terminal moraine, which, more or less distinctly determinable, has been traced from the eastern end of Long Island to the southwestern corner of Cattaraugus County, and onward into Pennsylvania. This moraine is shown here on maps 3 and 6–A.

As the ice-sheet withdrew toward the north, the surface which it had occupied was, for many reasons, very uneven, and in the depressions there were formed numerous lakelets and lakes. Into the smaller lakes and ponds especially, were swept, by running water and blown by winds, coarse materials and dust, so that they began at once to fill. Water-loving plants in due time took possession of their borders, and in time marshes were formed. In some of these bodies of waters are now found deposits of shell marl, which show that for a long period the lakes and ponds were inhabited by fresh-water mollusks. Sometimes below this marl, but usually above it, is found a layer of peat, the product of the partial decay of the vegetation. It is in such peat-bogs, sometimes buried in the peat, sometimes in the marl, that have been found most of the bones and teeth of the fossil animals recovered. Inasmuch as such deposits lie upon the Wisconsin drift, it is certain that these animals lived, at the localities where found, after the retirement of the glacier from that locality; how long afterward one usually can not be certain.

It is in such Late Wisconsin deposits that have been found the numerous remains of mastodons on Long Island, on Staten Island, around New York City, and especially in Orange County (pp. 48–54). This county has furnished some of the most complete skeletons of mastodons ever discovered. Whether or not the conditions for their existence were more favorable in this region than in that between this county and the Finger Lake region may be regarded as doubtful; but it is certain that the conditions for the preservation of skeletons were extremely favorable.

A remarkable case is presented at Cohoes, where a part of a skeleton of a mastodon was found in one of the great pot-holes existing there, and another part of the same skeleton in a neighboring pot-hole. The case is discussed below.

In the western half of the State, after the foot of the glacier had retired beyond the divide between the present northward and southward flowing streams, bodies of water began to collect between the divide and the foot of the glacier. To these bodies, regarded as lakes, changing from time to time their dimensions and their outlets, have been given various names. At first, the waters that collected in the Finger Lake region found their outlet southward through the Susquehanna River; later through the Mohawk and Hudson; then westward into the Mississippi drainage; afterward through a channel leading around west and north of the Adirondacks and into Lake Champlain and down the Hudson; and finally, as now, into the St. Lawrence River (map [34]).

The waters of the Erie basin, for most of the time, found their outlet toward the west into the Mississippi; but at a later time they escaped for a while eastward through central New York into the Mohawk. For information regarding these lakes one must consult Leverett and Taylor (Monogr. LIII, U. S. Geol. Surv.) and Fairchild (Bulls. 127, 160, N. Y. State Mus.).

From a study of the geological history we may arrive at some approximately correct ideas as to the time when the mastodons, elephants, horses, giant beavers, etc., lived within the limits of the State. Of these animals, apparently none of the specimens discovered up to this time belongs to any pre-Wisconsin stage, except the horse whose tooth was found at Throg’s Neck (p. [183]). The history of our extinct horses and the depth at which the specimen was found indicate that the animal had lived either during the first or the second third of the Pleistocene.

We may be certain that none of the mastodons (p. [49]) which have been reported from Long Island lived there while the northern border was occupied by the glacier, and the remainder by the ocean. Not until the land had risen to about its present level could mastodons have become buried in the muck-filled ponds where they have been met with. Where the glacier front was when mastodons got foothold on the island we can not tell certainly; but it required perhaps hundreds or probably thousands of years for the elevation of the island to the extent of about 100 feet. We can hardly doubt that the mastodon lived on up to near, possibly into, the Recent period (see map [34]).

It is interesting to speculate on the time and manner of entombment of the skeleton, described on page [56], which was found at Cohoes, part in one pot-hole, part in another not far away. Hall adopted the theory that the carcass of the mastodon had been frozen in the glacial ice and, on the thawing of this ice, had been dropped into the pot-holes. In fact, he thus explained the frequent presence of mastodon skeletons in swamps. We have, however, no evidence that mastodons were ever thus frozen up in the ice of the glacier; but there is a possibility that this happened sometimes. If a skeleton should thus have been engaged in the moving stream of ice it is not probable that it would ever have emerged in a recognizable condition. In the production of cracks and crevices in the glacial ice, of which Hall spoke, the bones would have been broken up and scattered, if not ground to powder. If a cadaver had been frozen in the ice for any considerable time it would certainly have come out in such a waterlogged condition that it would hardly have floated. Weighted down by its heavy tusks, it would have drifted against rocks and at least the tusks would probably have been broken off. If we exclude the idea that the mastodon had first been frozen in the glacier, the writer sees no reason for denying that it might thus have been transported for some distance; but little is gained by granting it. The animal could as well have lived near Cohoes as farther up the Mohawk.

As stated on another page, James Hall concluded that the pot-holes belonged to some preglacial time. Professor H. L. Fairchild has expressed in a letter to the present writer the following opinion:

“When the ice-sheet melted from Cohoes the locality was 355 feet lower than it is to-day. Deep estuary deposits partially filled the Hudson Valley and buried the Cohoes district. The Mohawk channel at Cohoes is excavated through marine sediments. There is no suggestion of any river channel there previous to the present river work. The pot-holes are post-glacial, but they probably represent a more copious and vigorous flow than that of the present river. That was supplied by the diminishing Iromohawk, the latest outflow through the Mohawk Valley of the Iroquois water. In this view the pot-holes were drilled by the latest glacial waters.”

It appears that, when the mastodon skeleton fell into the pot-holes, these had been drilled long before; for the principal one had become filled with gravel to a depth of at least 10 feet. They were, therefore, probably well above the stream-level, except in times of high-water. However the carcass reached the locality, it must have arrived in a complete state. Had it already attained an advanced stage of decay, some limbs or the feet or the lower jaw, probably the whole head, weighted down as it was by the heavy tusks, would have dropped off. It may be assumed that the skeleton was lying on land or in some pond not far above the pot-holes. The flesh was not wholly decayed, and the bones were held together by the ligaments. While the skeleton was in this condition the river rose and swept it over the first pot-hole, where the right leg dropped off; and then onward over the second, where more of it was deposited. Some unimportant parts may have been carried farther, and some of the missing bones may have decayed in the pot-holes. After the bones were deposited there the pot-holes became slowly filled up, probably mostly during times of high-water, with muck and branches and trunks of trees of several species (Hay, Science, n. s., vol. XLIX, 1919, p. 378).

The retreat of the Wisconsin ice-sheet far beyond the St. Lawrence and the rise of the land to its present elevation, 350 feet above the sea at Cohoes, belong to the closing chapter of Pleistocene history. When the Cohoes mastodon was buried the ice-sheet was probably already north of the St. Lawrence and, as Professor Fairchild writes, 150 feet of the rise of the land had already occurred. The time could, therefore, not have been long before the beginning of the Recent epoch. If these animals lived at such a late time at Cohoes they doubtless existed at the same time in all parts of the eastern region where their remains have been discovered. They may have been able to occupy Long Island a little earlier than places further north, but the interval would be geologically inconsiderable.

The writer has learned of no discoveries of mastodon bones in materials laid down by the marine waters that occupied Lake Champlain, the St. Lawrence Valley, and that of Ottawa River, or in deposits overlying these marine beds.

On the basis of one of Professor H. L. Fairchild’s plates (Bull. 127, N. Y. State Mus., plate XXXV) the writer has prepared map [34], which is intended to show the position of the Wisconsin ice-sheet in New York after it had retired somewhat north of the divide. This divide is marked by a line of dots. The area then occupied by the ice is stippled. Lake Erie was already nearly free from ice and was discharging its water by way of the Mississippi. Impounded waters from the melting glacial ice were collecting in the region of the Finger Lakes, forming Newberry Lake, and escaping down the Susquehanna. The Mohawk afforded outlet for the water from the southeastern lobe of ice. Fairchild’s plates 36 to 42 show the successive positions occupied by the ice-front as it retired northward and the various lakes that were formed.

Although not many species of vertebrate animals have been found in the Pleistocene deposits of New York, a large number of localities have furnished remains of the mastodon, Mammut americanum. These localities are recorded and brief descriptions of the remains and their geological environment have been presented on pages [48]–63. The localities are indicated on map [34]. It will be seen that several specimens have been found on Long Island and many in Orange County, in the southeastern corner of the State. In the western half of the State most of the finds occur within the area once occupied by the successive lakes. The animals could have lived there only after the ice-sheet and the lake waters had disappeared. It will be seen that a few finds have been made close to the shores of the present lakes. The animals must have lived there at the very end of the Pleistocene, if not within the Recent epoch.

The finds of other vertebrates are recorded on the following pages: Equus sp. indet. on page [183]; Platygonus compressus on page [212]; Bison bison on page [266]; Odocoileus virginianus on page [226]; Cervus canadensis on page [235]; Rangifer caribou on page [245]; Elephas columbi on page [149]; Elephas primigenius on page [131]; Castor canadensis on page [272]; Castoroides ohioensis on page [272].

In 1850 (Proc. Amer. Assoc. Adv. Sci., vol. II, pp. 255–256), W. C. Redfield reported that he had received remains of a fox of the genus Vulpes from Gulf Summit, Broome County. The lower jaw and other bones had been discovered in a cutting of the New York and Erie Railroad, 40 feet below the natural surface. The deposit above these bones was evidently the Wisconsin drift. The fine clay inclosing the bones may have belonged to the Sangamon, or even some older interglacial deposit. It is impossible to say whether this fox was Vulpes fulvus or Urocyon cinereoargenteus.