Chapter XVII: On the Theory of the Pleistocene Terraces of the Coastal Plain (19)

Baird supposed that these bones had in most cases been washed in from above through sink holes. This collection, or some of it, was brought by Baird to the Smithsonian Institution; and they, or some of them, are in the collection of mammals; but the bulk of the collection has apparently been lost. All of these animals belong evidently to either the very late Pleistocene or to the Recent period.

A cave at Frankstown has furnished fossils of about Middle Pleistocene time. In 1908 (Ann. Carnegie Mus., vol. iv, pp. 228–233) and again in 1912 (Proc. Internat. Zool. Congr., Boston, 1907, pp. 748–752), Dr. W. J. Holland gave an account of the discovery of vertebrate fossils in a fissure in limestone rock at Frankstown, Blair County. This village is situated on the Frankstown Branch of Juniata River, a little more than 2 miles north of east of Hollidaysburg. The fissure was excavated in a Devonian rock known as the Lewistown limestone. The quarries are reported to be in the village and on the top of a hill that rises about 400 feet above the banks of the Juniata. According to the Hollidaysburg topographical sheet, the 920–foot line crosses the river just above the village. The highest hill, 1,260 feet above sea-level, is 0.3 mile away toward the northwest. In this hill, as Dr. Holland stated, there are several small caves. The one which furnished the fossils appeared to be about 40 feet in length, averaging from 6 to 8 feet in width, and at the most was not more than 10 or 12 feet high. The floor was about 30 feet below the top of the hill. The fissure appeared to have once continued up to the surface, but the opening had been filled with fallen blocks of limestone. The floor of the cave is described as being occupied by about 2 feet of red soil, everywhere traversed by bands and layers of dark materials charged with organic matter. With the finer deposits were mingled fragments of rock, some being large blocks. The fossil remains appear to have been carefully collected, but were mostly fragmentary. They were only cursorily studied at the time of Holland’s writing and nothing has since been published on them. The number of species obtained was estimated to be from 30 to 40. The following genera and species are mentioned:

Meleagris sp. indet. Megalonyx sp. indet. (p. 31). Tapirus sp. indet. (p. 203). Mylohyus pennsylvanicus (p. 214). Odocoileus virginianus (p. 227). Cervalces? sp. indet. Bison sp. indet. Mammut americanum (p. 69). Sciurus sp. indet. Ondatra sp. indet. Erethizon sp. indet. Lepus sp. indet. Ursus americanus. Arctotherium haplodon. Mephitis sp. indet. Canis sp. indet. Felis? sp. indet.

After the foregoing had been put in type Mr. O. A. Peterson, of the Carnegie Museum, sent the writer a revised list in which additions are made. The following are the most important:

Cryptobranchus sp. indet. Rana catesbiana? Clemmys insculpta. Blarina sp. indet. Ænocyon dirus. Canis priscolatrans? Spilogale putorius. Brachyprotoma putorius. Boötherium bombifrons. Equus sp. indet.

Besides these forms, remains belonging to bats, various birds, snakes, and batrachians have been recognized. Of the fossils identified generically or specifically those belonging to _Megalonyx_, _Tapirus_, _Mylohyus_, _Cervalces_, _Mammut_, and _Arctotherium_ are certainly extinct. Probably, too, the bison and the species of _Felis_ are extinct. There are, therefore, pretty certainly close to 50 per cent of the species which are no longer living. This percentage and the history of some of the genera make it improbable that the assemblage belongs to the Late Wisconsin stage. Some of them could hardly have been living during the Wisconsin, when the foot of the glacier was within 100 miles toward the northeast and northwest. On the other hand, there are no species or genera present which make it necessary to refer the collection to the first interglacial. The assemblage probably belongs to the middle Pleistocene.

Coming now to the very southwestern corner of the State, we find that. _Elephas columbi_ has been met with in the bed of Hargus Creek, 3 miles above Rogersville, in Greene County (p. 150), and _E. primigenius_ on Gray’s Fork of Ten Mile Creek, near Graysville (p. 133). In the Rogersville Folio (No. 146, U. S. Geol. Surv.), Dr. F. G. Clapp described the geology of this quadrangle. On his page 10 he briefly discussed the meager Quaternary deposits of the area. These he referred to the Carmichaels formation, and indicated his opinion that it belonged to very early Pleistocene. On the geological map it is represented as occurring along Ten Mile Creek at and just below Rogersville. The occurrence of a tooth of _Elephas columbi_ just above this town and of _E. primigenius_ just above Harveys (p. 133) renders it probable that other patches of the formation exist further up the stream and along some of its branches, and that the fossils were derived from that formation. It is, of course, possible that small patches of a later deposit exist there.

Reference has been made to the Carmichaels formation. The type locality is found at Carmichaels, on Muddy Creek in Washington County. The geological description of the locality has been presented by Marius R. Campbell in the Masontown-Uniontown Folio (No. 82, U. S. Geological Survey). The formation occurs extensively along Monongahela River and other streams of western Pennsylvania. For information the reader should consult the Geological Survey Folios Nos. 144, 146, 121, 82, and 177. The deposits occur at levels considerably above the present streams and are regarded as having been laid down in old and now abandoned river channels and in tributaries of these. The time when this occurred is believed by many, if not most geologists to belong to the early Pleistocene, the Kansas stage, or possibly the Nebraskan. In the opinion of some geologists the glacial ice dammed the streams and caused their valleys to be filled with detritus. More recent Pleistocene deposits, possibly of Wisconsin age, occur at lower levels in some places south of the Wisconsin moraine; and perhaps the age of some of them has not yet been recognized. When remains of vertebrate animals are discovered, it is of great importance to determine, if possible, the exact levels of their origin.

On another page mention is made of the finding of a tooth of _Elephas primigenius_ at Lone Pine (p. 133), 7.25 miles south of southeast of Washington. This village is on Little Ten Mile Creek. No details of the discovery have been received. From Folio 144 of the U. S. Geological Survey it is learned that patches of the Carmichaels formation are found for several miles along Ten Mile Creek, near the southern boundary of the quadrangle. It seems probable that there may be patches of the same deposit along Little Ten Mile Creek, in the neighborhood of Lone Pine.

As detailed on page 70, a mastodon tooth was found many years ago about 1.5 miles south of the village of Hickory, Washington County, about twenty miles southwest of Pittsburgh. Westland Run empties into Chartiers Creek, and this into the Ohio at Pittsburgh. The geology of Burgettstown and Carnegie Quadrangles has been described by E. W. Shaw and M. J. Munn (Folio 177, U. S. Geol. Surv. 1911). No Pleistocene deposits are mapped on the stream mentioned; but just a little lower down, on Chartiers Creek, is a patch of the Carmichaels formation. Below Hickory somewhere there must be a Pleistocene deposit of some kind, and it is more probably early than late Pleistocene.

From the vicinity of Pittsburgh there have been reported remains of the mastodon (p. 69), of _Elephas columbi_ (p. 150), and of an undetermined species of elephant (p. 168). Neither of the elephants is certainly determinable. The mastodon, represented by fragments of bones and teeth, is said to have been found in the river bank, at the junction of Monongahela and Allegheny Rivers. It is impossible to determine the Pleistocene stage to which any of these proboscidean remains belong. As shown on the geological map of the Carnegie Quadrangle (Folio 177, U. S. Geol. Surv.) there are indicated here Pleistocene deposits of early, intermediate, and late stages.

Little information is furnished by a mastodon reported found on Dicks Creek in Butler County. The statements regarding the finding of elephant remains on French Creek near Meadville are vague and valueless (p. 168). Some remains of _Elephas columbi_ have been found at Tryonville, at a depth of 7 feet (p. 150). The town is on the Wisconsin moraine and the elephant probably belongs to the Late Wisconsin.

Nearly a hundred years ago a tooth of _Elephas primigenius_ was reported from a place in Erie County, called Beaverdam (p. 133). From Mr. Clyde C. Hill, civil engineer, Northeast, Erie County, the information is received that Beaverdam is a cross-roads hamlet about 23 miles south of the lake, near the prolongation of the western New York boundary line. This is within the area covered by Wisconsin drift, and it is pretty certain that the animal lived there after or near the close of the Wisconsin stage.

Just west of Erie a mastodon tooth has been found along Chase Creek (p. 70). Unless there are some unrecognized pre-Wisconsin deposits along this creek, the animal must have lived there at a time after the lake had retired to about its present limits. This would be near the very close of the Pleistocene epoch. The same conclusion must be arrived at from a study of the proboscidean remains (supposed to be those of an elephant) found at Girard.

Brief mention is made here of finds of fossil vertebrates in Pennsylvania which have not yet been mentioned; also, the localities are given where they are found, and citations of the pages where fuller descriptions are furnished:

A horse has been reported from Rutherford, Dauphin County (p. 185), and a peccary, _Platygonus vetus_ (p. 213), from Milroy, Mifflin County. Mastodons have been reported from Tunkhannock, Wyoming County; Berwick, Columbia County; Reading, Berks County; Jackson Township, York County; near Reedsville, Mifflin County; Chambersburg, Franklin County, and Bedford, Bedford County (see pp. 68, 69). _Elephas primigenius_ has been met with at Brookfield, Tioga County (p. 133); and somewhere about Chadd’s Ford, in Chester or Delaware County (p. 133).

OHIO.

(Maps 35, 36.)

The State of Ohio is partly glaciated, partly not. The unglaciated portion forms the southeastern border and constitutes close to 28 per cent of the whole surface. The glaciated area is mostly covered by the Wisconsin drift, which makes up 60 per cent of the whole surface. The remainder is covered by that part of the Illinoian drift-sheet which projects beyond the edge of the Wisconsin. This occupies about 12 per cent of the surface of the State. The unglaciated area contains Pleistocene deposits along the streams, especially along Ohio, Muskingum, Hocking, and Scioto Rivers. Probably the greater part of the materials forming these deposits were brought down the rivers which headed at the foot of the Illinoian and Wisconsin glacial ice-sheets. However, all that part of the country which was not covered by glacial ice was acted on by atmospheric agencies and suffered erosion. Hence abundant materials of non-glacial origin were swept down those tributaries of the Ohio which had their sources in the Alleghany region and down those which flowed through the unglaciated part of the State. Much of these materials was deposited along the banks of these streams and mingled with the débris from the glacial ice-sheet. Doubtless such deposits were being made during the whole Pleistocene epoch and were mostly swept away; or they may have been covered up by subsequent deposits; or the deposits of one stage may in many cases not be distinguishable from those of other stages. A perusal of chapter V of Leverett’s monograph of 1902 (Monogr. U. S. Geol. Surv., vol. XLI, 1902, pp. 228–252) and of the papers there cited, also of others published since that time, will impress the reader with the fact that an old drift, probably of Kansan or pre-Kansan age, has left traces of itself in Ohio just outside of the terminal moraine of the Wisconsin drift. This is found especially in Columbiana County; but, according to Wright (2d Geol. Surv. Pennsylvania, Z, p. 207) it extends as far westward as Canton, Stark County.

It is shown in Leverett’s paper that the streams, especially the larger ones, of southwestern New York, western Pennsylvania, and eastern Ohio had, at some time preceding that of this old drift, been deeply excavated into the underlying rocks, and that these ancient channels had become filled by the outwash from the older drift. Furthermore, terraces composed of this drift are now found along rivers of the region mentioned, at heights varying from 150 to as much as 500 feet above the present streams. Those old, deeply excavated valleys may therefore have once been filled to the highest terraces and since that time have been re-excavated to the level of the present streams. The ancient rocky floors in many cases lie now from a few to some hundreds of feet below the beds of the existing rivers. It is easily possible that the bones and teeth of early Pleistocene animals may have been buried in such valley fillings and such terrace deposits. Again, remains of such vertebrates may have been buried beneath the glacial “fringe” that has been mentioned. In such cases it may be impossible for one who is not a glaciologist, perhaps not even for him, to determine the real age of the fossils. It is, therefore, of the utmost importance that a record be kept of the exact spot where the fossil was found, so that at some future time the geology of the locality may be studied by a competent person. Naturally, other information, as that relating to the kind of deposit, depth of burial, elevation of place of burial, and the like, is valuable.

A discussion of the Illinoian drift-sheet, including that part found in Ohio, forms chapter VI of Leverett’s work of 1902 (Monogr. cit., pp. 253–291). As shown by his plate II, Illinoian drift covers a small area in the southwestern corner of the State, along Ohio River; then leaving the river and running first in a northeasterly direction, then directly north, it forms a narrow strip outside the border of the Wisconsin as far north as Richland and Holmes Counties. If it extends further east than this, it is concealed beneath the Wisconsin. It is to be expected that Illinoian drift will be discovered here and there in the greater part of the State beneath the Wisconsin where the latter shall have been penetrated in digging wells, in borings, and where streams have cut down through the later drift-sheet. In such places it will be possible to find remains of animals and plants buried in interglacial deposits laid down before the Wisconsin stage; that is, in either Sangamon or Peorian or even more remote times. On page 269 of the work just quoted, Leverett mentions a case near Lancaster, Fairfield County, where a black mucky soil was found between the Wisconsin and the Illinoian drifts. On page 273 of the same work is mentioned the occurrence of logs and pieces of wood at Bethel, Clermont County, in a gravel-bed beneath the Illinoian drift. This might be interpreted as indicating a deposit belonging to the earliest part of the Illinoian or to the Yarmouth.

The general aspects of the Illinoian drift are described by Leverett on his pages 270 to 285.

Deposits of Illinoian age may occur beyond the border of the ice-laid Illinoian drift and even beyond the Wisconsin as the result of outwash. Leverett (op. cit., p. 285) mentions the occurrence of what appears to be an Illinoian terrace along Sandy Creek, near Waynesburg, Stark County, at 70 feet above the stream, while the Wisconsin terrace is hardly 40 feet above the creek. High-level terraces are found along Licking and Muskingum Rivers from Hanover, Licking County, to McConnellsville in Morgan County, and are thought to be possibly of Illinoian age, while lower ones belong to the Wisconsin. Illinoian gravels and cobble are likewise met with along Hocking River (Leverett, op. cit., p. 288); also along the Scioto from Chillicothe nearly to its mouth. On lower-level terraces other deposits of Wisconsin age are to be looked for. Again it is seen how important it is that accurate information should be sought regarding the exact spot of interment of any vertebrate remains, as well as the elevation, the depth, and kind of materials passed through.

Map 35 has been prepared to show the distribution of the Wisconsin and Illinoian drift-sheets in Ohio. The driftless area, shown without shading of any kind, occupies the southeastern side of the State and forms a broad tract somewhat parallel with Ohio River. The Illinoian belt lies between this driftless area and the Wisconsin. Naturally it passes beneath the Wisconsin drift and probably underlies most of it. A part of the map is shaded by horizontal lines in order to show the position and extent of former Lake Maumee. This lake was an early predecessor of Lake Erie and emptied into Wabash River. The moraines laid down by the Wisconsin ice on its gradual withdrawal from the State are indicated by the stippled areas and by the letters at the sides of the map. Most of the names applied to these moraines in Ohio differ from the parts of the same moraines in Indiana. The Germantown, Eaton, and Englewood correspond to the Bloomington of Indiana; the Sidney to the Union City; the Loramie to the Salamanie; the Celina to the Wabash; and the Lima to the Fort Wayne.

Map 36 shows the localities where Pleistocene mammals have been discovered in the State and the relation of these localities to the drift-sheets and the moraines.

It is to be supposed that any animal whose remains are found in deposits overlying the Wisconsin drift lived there after the retreat of the ice-sheet from that locality. Any mastodon (maps 5, 7) that has been discovered within the area covered by the old Lake Maumee probably lived there after that lake had subsided. However, it might be possible to find along rivers, or deep cuts along railroads, animals that had lived there during Sangamon times; but this may be supposed to occur rarely. Mastodons, Nos. 34, 37, and 39 of map 7, probably lived and died after later Lake Warren had shrunken into Lake Erie.

Most of the fossil vertebrates that have been found in Ohio belong to the Late Wisconsin; that is, they lived in their respective localities after the glacial ice had retired from those localities. A few fossils may be credited to an interglacial stage, Sangamon or Peorian, which intervened between the Illinoian and the Wisconsin. Inasmuch as in the area occupied by the Illinoian drift this deposit may be cut through by rivers or railroads, it is possible that pre-Illinoian fossils might be discovered.

A tooth of _Elephas primigenius_ has been found at Waverly, Pike County, on Scioto River, as recorded on page 134. Along that river there are deposits of gravel and sand which were derived apparently from Illinoian drift, while below these Illinoian deposits is a Wisconsin terrace. The tooth above mentioned appears to have been found in a gravel-pit of the Norfolk and Western Railroad about the year 1900. The writer has not been able to secure any information as to the elevation of the pit. The elephant remains observed by Whittlesey along Scioto River, as mentioned on page 169, were probably buried in the Wisconsin terrace. A mastodon has been found in Pike County (p. 70), but the more exact locality is not recorded.

An important but apparently now lost and therefore indeterminable specimen of elephant is that to which was given the name _Elephas jacksoni_, described on page 168. It was found in the northwestern corner of Jackson County, on Little Salt Creek, probably a short time before 1838. The probability is that it was found in Wisconsin deposits, but its age is possibly greater. According to Leverett (op. cit., pp. 120, 121, 289), there are in this valley deposits which were probably laid down during the Illinoian stage. An elephant skeleton is reported to have been dug up many years ago in the village of Beverly, Washington County (p. 169), on Muskingum River. Leverett (Monogr. XLI, p. 157) states that glacial deposits belonging probably to the Wisconsin stage are found here at a height of 119 feet above the river. Inasmuch as the greater part of the village is below this level, the elephant probably belongs to Wisconsin time.

Further up the Muskingum, at or near Duncan Falls, there was found about 1857 a tooth of _Elephas primigenius_ (p. 135). The animal probably lived and died there at a time when the Wisconsin glacier was not far away. Other remains of the same species have been described from Zanesville. The bed which contained these is said to be at a height of 37 feet above the river and 20 feet from the natural surface of the ground. Inasmuch as drift outwash, believed to be of Wisconsin age, is built up here to a height of 100 feet above the river (Leverett, op. cit., p. 157), it is wholly probable that the elephant, like the one just described, lived in the vicinity of the Wisconsin ice-front. At Nashport have been discovered in swampy ground remains of _Castoroides_ (p. 273) and of _Mammut_ (p. 70). Although there is at Hanover, Licking County, across Licking River, a great dam of supposed Illinoian age and probably more or less hidden deposits of the same age along the river, the giant beaver and the mastodon just mentioned may not be older than the Wisconsin. Nevertheless, as they were found lying on gravel at a depth of 14 feet, they may have been buried there during the Sangamon stage. Along the eastern border of the State, in Columbiana County, on Salt Creek, in the southwestern part of the county, there was found, about 1845, a tooth of a horse (p. 186). It was discovered while a canal was being excavated and at a depth not to exceed 12 or 15 feet. The locality is apparently some miles south of the Wisconsin moraine. The animal lived there evidently at some time preceding the Wisconsin drift stage, possibly after the Illinoian, but quite as likely before the Illinoian. Not far away from where the horse was discovered, apparently on Little Yellow Creek, and probably not far from New Salisbury, there was found, about 1850, a fragment of the lower jaw of a tapir (p. 203). It probably lived at about the same time that the horse did. Near Millport a tooth, referred to _Elephas primigenius_, has been found (p. 135). The locality is beyond the Wisconsin moraine, but it is impossible to determine whether the beast lived there early or late in the Pleistocene.

At this point may be mentioned the discovery of remains of a peccary, supposed to be _Mylohyus nasutus_ (p. 215), and of _Mammut americanum_ (p. 70) in the southern edge of Lisbon, Columbiana County, apparently along Middle Fork of Little Beaver River. This locality is on the border of the Wisconsin drift-sheet, and the peccary and the mastodon might well have lived there with the horse and the tapir mentioned above.

Not many localities within the area of the Illinoian drift in Ohio have furnished vertebrate fossils.

Lyell in 1843, as stated on page 71, reported that teeth of mastodons and of elephants had been found on the Cincinnati side of the river, on the high terraces.

From Professor N. M. Fenneman the writer learns that Lyell’s reference could hardly apply to any other locality than Terrace Park or Milford. Here are found some fragments of an Illinoian terrace that would hardly be spoken of casually as such, while the Wisconsin deposit is present as an upper and a lower terrace.

In Hyde Park, as detailed on page 71, considerable parts of a mastodon and some remains of a horse (p. 185), probably _Equus complicatus_, have been discovered. The age of these remains certainly antedates that of the Wisconsin; and it is not improbable that the excavation was carried through the Illinoian drift into an older and probably interglacial deposit. Professor Fenneman writes that this area is only thinly covered by Illinoian drift and is also far beyond the limits of the Wisconsin outwash.

The occurrence of _Bison latifrons_ near Fincastle, in Brown County (p. 257), must be noted. The fine pair of horn-cores now in the Cincinnati Society of Natural History may have been buried in deposits of Sangamon age. It is not, however, impossible that they were in an interglacial bed below the Illinoian drift.

On page 135 there has been given an account of the finding of a skull of _Elephas primigenius_, somewhat more than a mile east of New Burlington. The locality is treated in proper detail in N. M. Fenneman’s paper entitled “Geology of Cincinnati and Vicinity” (Bull. 19, Geol. Surv. Ohio, p. 158). According to this account the skull was buried in a lacustrine silt laid down probably when the Wisconsin glacier was not far away from that region. The surrounding country is covered with Illinoian drift. This skull is now the property of the U. S. National Museum.

In the collection of the Ohio State Archæological and Historical Society at Columbus there are remains of _Platygonus compressus_, jaws and good teeth, which were found about a mile north of Chalfants, in Perry County, and along Jonathan Creek. This place is within the area covered by Illinoian drift. It is possible that the remains are as old as the Sangamon, but it is also possible that they belong to the close of the Wisconsin stage (p. 215).

The writer knows of no other fossil vertebrates that have certainly been found within the area occupied by the Illinoian till as a surface deposit.

As shown by map 36, by far the larger number of Pleistocene vertebrates which have been discovered in Ohio have been met with within the region occupied by the Wisconsin drift-sheet. One reason for this preponderance is the greater area included. Another reason may be found in the fact that the conditions were more favorable for the preservation of teeth and bones. Much of the country was flat and swampy and the bones buried in clay and muck have always been soaked with water. Also there has been less erosion going on. Erosion leads to exposure and therefore to destruction of skeletons.

On the map referred to are shown the various moraines that were left by the Wisconsin ice-sheet in its retreat toward the north. Inasmuch as most of the burials were in swamps resting on the drift, the animals must have lived and died there after the ice had left that vicinity; how long after one may not be able to determine. The mastodons and elephants which have been found close to the shore of Lake Erie, especially if buried near the surface, must have lived there at or after the time when the waters had shrunken into Lake Warren. Such cases are furnished by the mastodons and elephants found at Amboy (east of Ashtabula) (pp. 137, 150), at Cleveland (p. 79), and in Brownhelm Township, in Lorain County (p. 79). The town of Amboy is about 130 feet above lake level and the gravel-pit which there furnished _Elephas primigenius_ and _E. columbi_ was probably at about the same level. The writer has not been able to confirm any case in which remains of proboscideans have been met with on the south shore of the lake at a level lower than the Warren beach. Mastodons may be traced to a lower level at the western end of the lake. The one found in Springfield Township, Lucas County (p. 77), was buried in deposits only about 45 feet above Lake Erie. As shown by the topographical maps, the descent from this place and from Bowling Green, Wood County, to the lake is a gradual one. It may become possible to follow the presence of the mastodons, the elephants, and the giant beaver in Ohio up to the time when the lake assumed its present level.

For information regarding the several interesting discoveries of the giant beaver (_Castoroides ohioensis_) pages 273 to 275 may be consulted.

It is hardly necessary to take up one by one all the cases of vertebrates that have been met with within the area covered by Wisconsin drift. With the few exceptions noted below, their geological age is usually to be regarded as Late Wisconsin. Along the southern border of this drift, where the remains are deeply buried, it is not unlikely that they lie in a pre-Wisconsin interglacial deposit. Along Great Miami and Muskingum Rivers there is always a possibility that the fossils may occur in a terrace or in a deep valley deposit of Illinoian age.

About a mile east of Overpeck, Butler County, there has been found the skull of an extinct bear, _Ursus procerus_ Miller (Hay, Geol. Surv. Indiana, vol. XXXVI, 1912, pp. 772–776, figs. 71–73). It was found at a depth of 28 feet and about 3 or 4 feet above the limestone rock of that region. To the writer it seems quite certain that the Wisconsin drift had been penetrated and that the skull was in either a Sangamon interglacial deposit or something still older.

Columbus furnishes one of the rare cases in which horse remains have been found within the Wisconsin glaciated area (p. 186). We are then required to determine whether or not the horse, _Equus complicatus_, did not live there after the close of the Wisconsin stage. As said on the page cited, the first remains of horses discovered at Columbus were reported as having been found in crevices of the limestone and in the red clay filling such fissures. An examination of the Columbus Folio (197, U. S. Geol. Surv., p. 8) will show that in such crevices, south of Scioto River, a red clay is found which antedates the Illinoian drift, so that one might fairly refer the horse remains reported by Whittlesey to a pre-Illinoian interglacial stage, possibly the Aftonian. The horse-teeth found in the excavations at the penitentiary close to Scioto River may be as old as those found in the rock fissures, or they may have been buried in a post-Illinoian interglacial deposit. Such deposits have been found at various places in the quadrangle (fol. cit., p. 9).

As to the peccaries discovered at Columbus (p. 214), the writer sees no reason why they should not be regarded as belonging to the Late Wisconsin.

MICHIGAN.

To understand the Pleistocene geology of the southern peninsula of Michigan, it is indispensable to study Monograph LIII of the U. S. Geological Survey, by Frank Leverett and F. B. Taylor. The whole peninsula is overlain by glacial deposits laid down by the Wisconsin ice-sheet. A glance at their glacial map (plate VII) will indicate to the student the complexity of glacial problems in this region. The ice invaded the State from three sides: on the west from Lake Michigan, on the east from Lake Huron, and on the southeast from Lake Erie.

On the west, close to Lake Michigan, is a system of Lake-border moraines. This system has been traced more or less satisfactorily around to Saginaw Bay, Lake Huron. A little farther out, in the southwestern corner of the State, is Valparaiso moraine. This extends nearly to the northern end of the peninsula, where it connects with Charlotte moraine system. Farther in than the Valparaiso system is the Kalamazoo. This extends northeastwardly from the Indiana line to Barry County, where it turns east and at Jackson joins the Mississinawa system reaching northeast from the northeastern corner of Indiana. The Valparaiso and Kalamazoo moraines are in places closely associated. The attack on the eastern side of the State came principally from a lobe which flowed through Saginaw Bay. Nearest Lake Huron, following it around from Port Huron to the northern end of the peninsula and then turning west, the Port Huron moraine connected with the moraine along Lake Michigan.

Farther inland is the Charlotte system. On the north, just above latitude 44°, this joins the Valparaiso moraine, runs southward west of Lansing, then turns eastward, then northeastward, and connects with the Defiance moraine, which passes around the western end of Lake Erie. Reaching far out from the head of Saginaw Bay, and concentric with it, to Hastings, 100 miles away, are many minor moraines.

Besides the Wisconsin drift which forms the surface deposit in Michigan, there are, according to present indications, one or more pre-Wisconsin drifts. Leverett (Monogr. LIII, p. 72) mentions several localities where what appears to be more indurated till is encountered, sometimes at a depth of 100 feet. Taylor (op. cit., pp. 289–290) states that “a till older than that deposited by the Wisconsin ice-sheet seems to underlie more or less continuously all of the later, or Wisconsin, drift in Indiana and the southern peninsula of Michigan.” Along the western shore of Lake Huron, north of Port Huron and along the streams, as reported by Taylor (p. 290), there are several exposures of Illinoian till, in some cases as much as 30 to 50 feet thick. In one case there is an old soil at the top of this till. In such old soils it may be possible to find fossil vertebrates of Sangamon or Peorian times, horses for example.

The fossil vertebrates found up to the present time in Michigan are not numerous in species or individuals; all appear to belong to the middle or late Wisconsin times. A peccary, _Platygonus compressus_, has been found at Belding, Ionia County (p. 215). Two musk-oxen have been discovered in the State. At Manchester, Washtenaw County, has been found a fine skull of _Symbos cavifrons_ (p. 250). At Moorland, Muskegon County, was obtained a skull which has been called _Boötherium sargenti_.

Details regarding the mastodons which have been found in Michigan are given on pages 80 to 88. Only two localities in the State have furnished remains of _Elephas primigenius_. These are Three Oaks, Berrien County (p. 137), and Eaton Rapids, Eaton County (p. 137). _Elephas columbi_ has been encountered only once in the State, as far as is known; this was in the northern part of Jackson County (p. 151).

Elephants belonging quite certainly to either _E. primigenius_ or _E. columbi_, but for one reason or another not determined, have been found in four localities. These are East Saginaw, Saginaw County; Macomb County; Grand Ledge, Eaton County; and Buchanan, Berrien County. (See page 171.)

The giant beaver, _Castoroides ohioensis_, found a congenial home in the swamps of southern Michigan in the late Pleistocene. It has been met with somewhere in Berrien County; at Adrian, Lenawee County; at Ann Arbor, Washtenaw County; at Attica, Lapeer County; and at Owosso, Lapeer County (pp. 275–276).

INDIANA.

(Map 37.)

Whoever wishes to gain a knowledge of the Pleistocene geology of Indiana, as it is understood to-day, must study Leverett’s two great treatises, forming Monographs XXXVII and LIII of the U. S. Geological Survey. The first is entitled “The Illinois Glacial Lobe,” and was published in 1899; the second has the title “The Pleistocene of Indiana and Michigan and the History of the Great Lakes.” The portion of the latter monograph which deals with Michigan was written by F. B. Taylor. On pages 33 to 54 is a very full bibliography of the subject, consisting of about 400 titles.

From the glacial map of Monograph XXXVIII, plates V and VI, the writer has prepared map 37. This shows which part of the State has escaped glaciation, which has been subjected to the action of the Illinoian ice-sheet, and which has been covered by the last, or Wisconsin, glacial ice. It will be seen that about one-sixth of the State, that forming an irregular triangle whose apex is in Brown County and whose base is formed by the Ohio River, has never been covered by glacial ice. North of this is a bilobed area which is covered by till of Illinoian age. The rest of the State (somewhat less than two-thirds of it) is overlain by the débris left by the Wisconsin ice-sheet and subsequent deposits.

This northern area is to a great extent occupied by belts called moraines, along which the materials are usually coarse, often full of boulders, and frequently standing at a higher level than the surface on each side of them. These moraines show where for long periods during its retreat, or perhaps sometimes its advances, the ice-sheet paused and piled up a part of its load of rocks, gravel, and sand. It will be noticed that these moraines are somewhat concentric. On the right of the map are seen those moraines which were left by the ice-lobe which came down Lake Erie and later retired in that direction. Around the southern end of Lake Michigan are the moraines laid down by the ice of the Michigan lobe. The latter will be better seen on a glacial map of Illinois (Monogr. U. S. Geol. Surv. XXXVIII, plate VI). In their advance the two lobes met and coalesced and produced more or less irregular and anastomosing moraines.

On the right hand the moraines of the Erie lobe pass on into Ohio, where, however, they have often been given other names. On the left the moraines of the Lake Michigan lobe continue into Illinois and retain the same names. Both groups of moraines are prolonged into the southern peninsula of Michigan.

On account of the comparatively recent recession of the Wisconsin ice-sheet, the surface has not become eroded sufficiently to drain away the water which was left in depressions of the surface. A large part of Indiana is, or has been until recently, covered by swamps, lakes, and ponds, and in such localities the bones and teeth of vertebrate animals are best preserved during the early stages of fossilization. For this reason great numbers of teeth and bones, sometimes nearly whole skeletons, are met with in draining these swamps.

The southern border of the Illinoian drift, beginning at Cincinnati, follows Ohio River on the Kentucky side to Jeffersonville, then passes west of north into Brown County, whence, turning southwest, it strikes the East Fork of White River in Du Bois County; thence, following White River a short distance, it crosses the Wabash in Posey County. Northward, along this terminal moraine (map 37, figs. 1, 2) of the Wisconsin drift, the Illinoian, passing beneath this, disappears from the surface.

The surface of the Illinoian area is better drained than the Wisconsin area. Fewer fossils are found, and on various accounts they are of less value. Usually the exact locality and kind of deposit is not recorded. They may be found washed out of river and creek banks and may have in reality been buried in sediments that were laid down in Wisconsin times by the streams that carried away the mud, sand, and gravel from the glacier. The driftless area has been exposed for many geological ages to the influence of physical and chemical agencies. Its surface is, therefore, more diversified by hills and valleys and streams. In the limestones of this region caves are likely to be found, and these now and then furnish fossil bones and teeth.

During more than one of the glacial stages, perhaps during the earliest, the Ohio has served as the drainage-way for the waters that escaped from the glacial front. This subject is discussed by Leverett in Monograph XLI of the U. S. Geological Survey. As a result of this conveyance of glacial waters, the great trough of this stream may contain here and there deposits of the Illinoian stage or even of older deposits. Remains of _Megalonyx_ (p. 32) and of a horse (p. 186) have been found in the right bank of the Ohio, at Evansville, Indiana. At Bigbone Lick, Kentucky, close to the Ohio, horses have been discovered, _Mylodon_ and _Megalonyx_. These seem to occur in Sangamon interglacial beds overlying the Illinoian.

The Illinoian drift, probably everywhere in central and northern Indiana, underlies the Wisconsin. For some miles back from its terminal moraine the Wisconsin drift is thin; and possibly the Illinoian may. be found exposed in creek or river banks, or in railroad cuts. Furthermore, Leverett (Monogr. LIII, p. 72) writes:

“Probably a considerable number of the heavy deposits of drift in
central and northern Indiana are of pre-Wisconsin age, but as they
are largely sand and gravel, or loose-textured material, they can
not easily be discriminated from the Wisconsin.”

Such deposits are likely to be covered by only a thin layer of Wisconsin till. In many places in Indiana there have been found, deep down in the drift, old soils, muck beds, and vegetation in various forms. These beds appear to indicate interglacial deposits, most probably the Sangamon. Now, various genera of vertebrates, among them horses, tapirs, and mylodons, are not known to have existed after the Wisconsin glacial stage. If, however, remains of such animals should be collected in central or northern Indiana, or Ohio, or in southern Michigan, they might be reported as having been found in late Wisconsin beds, when really they had been derived from pre-Wisconsin interglacial soils.

It is interesting to observe that when the Wisconsin ice-sheet began to withdraw lakes began to form along its borders. One of these, Lake Chicago, appeared at the south end of the present Lake Michigan and for a long time discharged its waters down Illinois River. Another, Lake Maumee, occupied the basin of Maumee River as far west as Fort Wayne, and emptied down the Wabash. For details connected with the close of the Pleistocene in the region of Lake Michigan the reader should consult Frank C. Baker’s “The Life of the Pleistocene, or Glacial Period” (Univ. Ill. Bull. XVII, 1920).

A brief mention will be made here of the principal Pleistocene vertebrates that have been found in Indiana; also the localities where found, together with citations of the pages where fuller information is furnished.

The ground-sloth _Megalonyx_ has been collected near Evansville (p. 32). With it were secured remains of an undetermined bison (p. 257), a Virginia deer (p. 228), a horse (p. 186), a tapir (p. 203), and the dog _Ænocyon dirus_ (p. 32). Peccaries have been found in Gibson County (p. 216), in Wabash County (p. 218), and two species at Williams, Lawrence County (p. 217). At the same place was discovered the shell of a box-tortoise. Remains of deer have been discovered somewhere in Vanderburg County, including the existing deer and an extinct species, _Odocoileus dolichopsis_; at Harrisville, Randolph County; and at Roann, Wabash County. Bisons of an extinct species have been secured at Vincennes (p. 258).

The existing bison appears to have been found in Jasper County (p. 268). Of musk-oxen, _Symbos cavifrons_ has been collected at Hebron, Porter County (p. 252); at Wailesboro, Bartholomew County (p. 251); somewhere in Randolph County (p. 252); and probably in Beaver Lake, Newton County (p. 252). The existing musk-ox, _Ovibos moschatus_, has been discovered near Richmond (p. 252).

Mastodon remains are not uncommon, especially in the northern half of the State. It is hardly to be supposed that these animals were more abundant there during the late Pleistocene than in many other places in the region east of the Mississippi. The conditions for their preservation were evidently more favorable there than anywhere else, unless in Orange County, New York. Burial in swamp mud kept the bones from decay; and the imperfect drainage protected them from destruction by erosion. The various finds are described on pages 88 to 100.

Elephants are less well represented in Indiana than are the mastodons, but are not rare (pp. 138, 151, 171). Two species were present in the State, _Elephas primigenius_ and _E. columbi_. Beavers were doubtless abundant, but there appears to be no definite record of any find. However, the giant beaver has been recorded from several localities (pp. 276 to 278).

The great extinct dog _Ænocyon dirus_ was first found near Evansville (p. 32), and the coyote, _Canis latrans_, has been reported from Boone County. The latter is said to have been found in association with the mammoth (Cope and Wortman, 14th Ann. Rep. Geol. Surv. Indiana, p. 7).

ILLINOIS.

(Map 38.)

As a foundation for a knowledge of the Pleistocene geology of Illinois, the student must take Leverett’s work entitled “The Illinois Glacial Lobe.” This is Monograph XLVIII of the U. S. Geological Survey, a volume of 817 pages, with maps and figures. For a knowledge of the changes which occurred around the south end of Lake Michigan on the retirement of the Wisconsin glacier, see Dr. Frank C. Baker’s work, “The Life of the Pleistocene, or Glacial, Period” (Univ. Ills. Bull. XVII, 1920).

Illinois is eminently a glaciated State, as is to be recognized on Leverett’s plate VI. A little triangle in the northwestern corner, comprising about 600 square miles, and an irregular tract of perhaps 3,000 square miles at the southern end of the State constitute the whole of the unglaciated area out of 56,650 square miles. Two glacial stages are prominent, the Wisconsin and the Illinoian. The first was laid down by the Lake Michigan lobe, which sent its icy mass southwestward as far as Shelbyville. Westward the border moraine extends to Peoria, then north to west of Princeton, then northeast to enter Wisconsin 55 miles west of Lake Michigan. Eastward, of course, the deposits of till and the moraines extend into Indiana. North of the Shelbyville moraine is the Champaign. A more powerful moraine is the Bloomington, which forms a loop through the State, extending from Danville, Illinois, through Bloomington to Peoria, where it appears to have overridden the Shelbyville and thence northward, forming the outer border of the Wisconsin drift area. North of this moraine is located that called the Marseilles, while sweeping around the south end of Lake Michigan into Indiana and Michigan is the Valparaiso system.

South and west of the area of the Wisconsin drift is the Illinoian. At Mount Vernon the border crosses the Wabash and traverses Illinois, striking the Mississippi River at Carbondale. It then follows the Mississippi north to a point above Keokuk, where it enters Iowa. It reenters Illinois between Rock Island and Clinton and extends into Wisconsin.

On Leverett’s map (Monogr. XXXVIII, plate VI) there is indicated in northern Illinois, between the Illinoian and the Wisconsin, a tract supposed to belong to the Iowan; but Alden (U. S. Geol. Surv., Prof. Pap. 106, 1918, p. 173) holds that there is no good evidence that the Iowan extends into southern Wisconsin and Illinois. The supposed Iowan (op. cit., plate III) is mapped as Illinoian.

The glacial stage which preceded the Illinoian is the Kansan. This in Iowa extends eastward to the Mississippi, and one might naturally expect that it would be found underlying the Illinoian east of the river. Leverett (Monogr. XXXVIII, p. 105) presents evidences of its presence in western Illinois. Among these evidences is the presence in Hancock and Adams Counties of another till sheet below the Illinoian and separated from it by a black soil. This Kansan or some other pre-Illinoian till sheet has been found in many places in Illinois (op. cit., pp. 107–118).

Animal remains are not likely to be inclosed in the materials of the moraines or of the intermorainal till; but this is possible. A musk-ox or a hairy mammoth might have died not far away from the foot of a stationary or advancing glacier and its bones might have become incorporated in the moraine. Furthermore, inasmuch as any glacial stage began while the glacier was yet in the far north and ended only when it got back there, many non-glacial deposits belonging to that glacial stage were probably laid down south of it; and it would be difficult or impossible to distinguish these from interglacial deposits. However, it was these deposits which were laid down after the glacial ice had withdrawn, whether glacial or interglacial, which are of more interest to the palæontologist, because in them are to be found the fossil remains of animals and plants.

The last of the interglacial stages, that which immediately preceded the Wisconsin and followed the Iowan, is known as the Peorian. This takes its name from a locality a few miles east of Peoria (Leverett, Monogr. XXXVIII, p. 187). Here the Shelbyville till sheet is underlain by a bed of fossiliferous loess from 8 to 12 feet in thickness. Beneath the loess is fully 100 feet of Illinoian drift. This loess seemed to the geologists who examined it to be a deposit of more recent date than the Sangamon.

The Peorian interglacial stage and the preceding Iowan glacial stage have received much attention within recent years. In 1917 (Geol. Surv. Iowa, vol. XXVI, pp. 49–212), Alden and Leighton presented the results of their studies on the Iowan drift and the loess associated with it. In 1918 (U. S. Geol. Surv., Prof. Pap. 106, pp. 1–356), Alden dealt with the Quaternary geology of southeastern Wisconsin. The results of these investigations have been to establish the fact that a sheet of till intermediate between the Illinoian and the Wisconsin had been laid down, that which had already been designated as the Iowan; furthermore, that immediately following this there was deposited a covering of loess. It was further concluded that this is the main loess deposit, much of what has been regarded as Sangamon loess being really loess of a later stage, the Peorian.

As no Iowan drift is known to be present in Illinois to separate the loess of the Sangamon from the Peorian, it must be difficult, often impossible in our present state of knowledge, to distinguish the one from the other. The Sangamon loess was laid down probably long after the Illinoian ice disappeared, so that there was time for the Illinoian drift to become leached and otherwise modified and for the accumulation of old soils and peat-beds.

On the other hand, the old soils of the Peorian stage are likely to overlie the loess. Unfortunately, the desired indications of geological age are not always present where bones and teeth are found; or, if present, are not always observed. We must, therefore, make our assignments of fossils to one stage or the other with great circumspection or leave the decision in abeyance.

Reference has already been made to the presence of Kansan drift in western Illinois and of black soils intervening between it and the Illinoian. Such soils must be referred to the Yarmouth interglacial stage. Whether or not still older glacial or interglacial deposits occur in Illinois is problematic.

In Illinois any considerable number of species of fossil vertebrates are rarely found together. The localities are widely scattered and a single species or two in each is the rule (map 38). In later glacial deposits around the south end of Lake Michigan have been discovered the dogfish _Amiatus calvus_ and a sun-fish belonging to the genus _Lepomis_. Baker (Univ. Ill. Bull. XVIII, p. 85) reported the humerus of the merganser, _Mergus serrator_, from the same region. The ground-sloth _Megalonyx jeffersonii_ (pp. 33–34) has been found at Urbana, Galena, and Alton.

The few horses are described on page 187. Peccaries have been found at three localities (p. 218). For the specimens of deer that have come to light, see page 229. A species of _Cervalces_ and the moose _Alces americanus_ have been met with in Will County (p. 107). The reindeer has been recognized from poor materials found at Alton. The prong-horn _Antilocapra_ appears to have lived in the region of Galena, as shown by Wisconsin specimens. The remarkable antelope _Taurotragus americanus_ has been found at Alton (p. 339). As to the musk-oxen and the bisons, the reader may refer to pages 251, 259, 268; for the mastodons and elephants, to pages 100, 140, 152, and 176.

Of the rodents, the muskrat has been found about Chicago; the pocket gopher at Alton and Galena; the ground hog at the same places (p. 343). The beaver (p. 339) likewise occurs at Alton. The giant beaver, _Castoroides ohioensis_, has been collected at four widely removed places (p. 279). The rabbit, _Sylvilagus floridanus_, was included among the animals found in the lead crevices of the region about Galena, where also have been found an extinct species of raccoon, _Procyon priscus_, what appears to be a large dog _Canis_ (or _Ænocyon_) _mississippiensis_, the coyote, _Canis latrans_, and the fox _Urocyon cinereoargenteus_. The bear, _Ursus americanus_, and the common gray wolf, _Canis nubilus_, appear to have existed in the middle Pleistocene at Alton.

A skull of _Felis couguar_, the yet existing panther or mountain lion, has been found in Randolph County, in the bed of Kaskaskia River. It probably belongs to the late Pleistocene.

A considerable fauna has been secured in the lead region about Galena, in Illinois, Iowa, and Wisconsin. The collectors and describers of this were not careful to designate the localities, and in some cases these can not at present be determined. These collections are discussed on page 343, in the account of the geology of Wisconsin.