ILLINOIS.
1. Cairo, Alexander County.—The collection of the Buffalo Society of Natural History contains a tooth of an elephant, an upper left second true molar, apparently belonging to Elephas primigenius. It is reported to have been found at Cairo, at a depth of 95 feet below the bed of Ohio River. It was probably discovered in preparing the foundations of a railroad bridge. It has 15 ridge-plates, besides the front and rear talons. The length of the base, in a straight line, is 156 mm. There are 10 plates in a line 100 mm. long, a number too great for E. columbi. The tooth is unworn. It has suffered no injury, as from being rolled along the river bed; hence the animal probably died near where the tooth was found. It is impossible to assign the tooth with certainty to any particular stage of Pleistocene times. It seems most probable that the animal lived at the time the Illinoian ice-sheet was only a few miles away; the depth at which it was buried in the filling of the river channel appears to lend confirmation to this view.
2. Ashland, Cass County.—In the U. S. National Museum (No. 2195) are some remains of an elephant, referred to Elephas primigenius, found at Ashland in the spring of 1901. The remains consist of pieces of one tusk, the symphysis of the lower jaw, the right and left upper hindermost molars, the right lower last molar, a fragment of the rear of a much-worn upper second molar, and another of a correspondingly worn lower second molar. They were found in tilling a farm near Ashland by Mr. J. W. Arnold, of Jacksonville, Illinois.
The upper teeth resemble greatly those figured by the writer in his report on the Pleistocene Mammalia of Iowa (Iowa Geol. Surv., vol. XXIII, plate LIX); but the teeth from Ashland are more worn than those found in Milwaukee. The last molars from Ashland are worn back to about the eleventh ridge-plate, and the second molar is worn so that only its rear portion remained. The length of the upper molars is about 275 mm. The height of the eleventh plate is 185 mm.; the breadth of the grinding-surface is 90 mm. One or two of the hinder plates are missing, but evidently there were at least 24. There are 9 or 10 ridge-plates in a 100–mm. line on the worn surface; farther towards the base 8 plates in the same space. The ridge-plates are little bent; the enamel is thin and little sinuous in its way across the worn surface of the tooth.
The lower last molar is 315 mm. long, 152 mm. high, and 85 mm. wide. It is thus longer than the upper molars, slightly narrower, and not so high.
A fragment of the hinder end of what appears to be the lower left second molar shows 7 ridge-plates remaining. These form two series, an inner and an outer, entirely separate from each other. This condition is sometimes seen in little-worn teeth.
The geology of this region may be studied on the Tallula-Springfield Folio, No. 188 of the U. S. Geological Survey. The Tallula Quadrangle includes a narrow strip of the eastern border of Cass County. Here the surface forms a nearly level prairie. According to the geologists Shaw and Savage, the surface in the region next to Cass County and much of the rest of the quadrangle is covered by a blanket of loess. Its thickness varies from 4 to 20 feet; under this, sometimes, in wells, is to be found a dark-colored ill-smelling deposit, of no great thickness, which is believed to represent the Sangamon stage. Underlying the loess everywhere is the Illinoian drift.
As regards the geological age of the elephant described above, it is quite certain that it lived after the Illinoian stage. It is quite probable, too, that its teeth and bones were found in the loess which overlies the Sangamon soil in some places in the quadrangle. This loess may have accumulated during the Iowan glacial stage or during the succeeding Peorian interglacial. Considering what we know about the habits of Elephas primigenius, it appears most probable that the animal in question passed its life during some part of the Iowan.
3. Kewanee, Henry County.—In the collection of the University of Illinois, at Champaign, is a fragment of an upper molar of Elephas primigenius, found at Kewanee. It was discovered in 1910, in making an excavation for the National Tube Company, and was presented to the university by Mr. J. E. Kemp, at that time engineer in charge of the work of excavation. This gentleman has furnished very exact information regarding the discovery of the tooth and the nature of the deposits passed through.
Mr. Kemp himself saw the tooth taken out and states that it was found at a depth of about 12 feet. As to the materials passed through, Mr. Kemp writes:
“After the first 2 feet of soil carrying organic matter we have 5 feet of yellow clay above the ground-water level, and below this approximately 3 feet of yellow clay which becomes very soft unless carefully drained before working. This yellow clay then merges into bluish clay, hard and better packed, going to a depth of approximately 20 to 21 feet. At this level we meet with that black soil which is known locally as ‘the chip yard’ and which contains vegetation and pieces of wood, as you describe. This ‘chip yard’ is a softer stratum than the overlying blue clay and caused difficulty in the excavation of a hole approximately 20 feet by 30 feet and 20 feet deep, as the vibration of the reciprocating engines in the building caused the bottom to rise in little hillocks over night, and the last 2 feet of excavation had to be dug out and 24 inches of concrete placed in the bottom, in order to preserve the excavation.”
At Galva, 10 miles southwest of Kewanee, in cuttings along the railroad, is found a section which illustrates the geological situation at Kewanee (Monogr. XXXVIII, U. S. Geol. Surv., p. 126, plate X). There is at the top 4 feet of loess, 1 foot of Sangamon soil, 4 feet of Illinoian drift; in another section nearby there are 12 feet of loess, 2 feet of Sangamon soil, and 40 feet of Illinoian drift.
Another section at Galva is described by Leverett (op. cit., p. 130). The loess is 15 feet thick, beneath which is a mucky soil about 1 foot in depth, which caps the Illinoian till sheet. In this soil a log about a foot in diameter and several feet long was found embedded. Alden and Leighton (Iowa Geol. Surv., vol. XXVI, p. 170) mention this occurrence.
From these examples it becomes evident that the “chip bed” at Kewanee is a Sangamon soil overlain by loess. The elephant tooth at a depth of 12 feet must have been buried in the blue clay. This, however, is probably the unweathered part of the loess. If so, the mammoth tooth found at Kewanee is to be referred to the early Peorian stage.
4. Penny’s Slough, Henry County.—In the collection of the Davenport Academy of Science is a large upper left hindermost molar tooth, labeled as having been found in Penny’s Slough. It is very large, the length along the base being 357 mm. (about 14 inches), and the height of the eighteenth plate is 175 mm. There is an unusual number of the plates, apparently 27. There are 7 plates in a line 100 mm. long. The tooth is moderately worn. There are 2 large roots in front and 2 rows of smaller ones behind these. The base is straight and the plates little warped.
Mr. C. C. Martin, of Geneseo, Illinois, county surveyor of Henry County, has informed the writer that Penny’s Slough is located in sections 17, 18, 19, and 20 of township 18 north, range 3 east, in the northern part of the county and on Rock River. On Leverett’s glacial map of this region (Monogr. U. S. Geol. Surv., XXXVIII, plate VI) the area is indicated as being occupied by sand and gravel plains and terraces of Wisconsin age. It seems most probable that this elephant lived when the Wisconsin glacier was not far away. However, there is a variety of Pleistocene formations in that region and the elephant in question may belong to the Iowan or to the Illinoian glacial stage.
5. Kendall County.—In the collection of the National Museum is a plaster cast made from a tooth of Elephas primigenius, found somewhere in Kendall County, but the present location of the original tooth is not known. It had a length of 280 mm. along the base. There appears to have been 20 plates, 8 in a 100–mm. line. The tooth seems to have resembled greatly one of E. primigenius which was brought from Alaska.
Kendall County is mostly occupied by moraines formed during the Wisconsin stage of the Pleistocene, especially moraines which were built up just before the retirement of the ice into the basin of Lake Michigan. Probably the elephant which possessed the tooth lived during the latter part of the Wisconsin stage.