Both Greene and Madison counties are occupied by the Illinoian drift-sheet. The horse-teeth found in these counties might have come from Sangamon deposits; or possibly the Illinoian drift had been passed through and Yarmouth interglacial had been entered.

The geologists J. A. Udden and E. W. Shaw (Belleville-Breese Folio, No. 195, U. S. Geol. Surv., p. 7) have noted in those quadrangles deposits which may consist of pre-Illinoian till; also old black soils which may belong to the Yarmouth. The quadrangles mentioned lie along the southern border of Madison County. The old soils were found at depths varying from 30 to 75 feet. In this region, too, the Illinoian drift is overlain by a blanket of loess. To arrive at any valuable conclusion, one ought to know just where specimens are found and at what depths and in what kind of deposits. On the other hand, the information is of the most meager kind. The specimens mentioned are not in a collection made by McAdams and now in the National Museum.

MARYLAND AND DISTRICT OF COLUMBIA.

(Map [17].)

1. Marshall Hall, Charles County.—In the U. S. National Museum is an upper right molar, first or second, of a horse labeled as found at this place. It is credited to Mr. O. N. Bryan, who, some years ago, contributed many articles to the museum. The conditions of discovery are not known. The length of the grinding-surface is 28 mm., the width 27 mm. It probably belongs to Equus leidyi. According to Shattuck’s map of the Pliocene and Pleistocene of Maryland (Maryland Geol. Surv., 1906, plate I) this locality is occupied by Talbot deposits. Shattuck regards the Talbot as belonging to late Pleistocene times. The present writer does not accept this view.

2. Georgetown, District of Columbia.—In 1835 (Med. and Phys. Researches, p. 267), Dr. Richard Harlan acknowledged the receipt, at the Academy of Natural Sciences of Philadelphia, of remains of a fossil horse found at Georgetown in constructing the canal along the Potomac. These were probably teeth and had been sent by Colonel I. J. Abert, of Washington. They ought now to be in the Academy mentioned. In 1850, R. W. Gibbes (Proc. Amer. Assoc. Adv. Sci., vol. III, p. 67) presented before the American Association of Sciences a specimen (a tooth?) which he said came from the bank of the Potomac and was associated with a tooth of Bos (Bison). How he came to have this was not related, nor is it certain that it was found near Washington.

3. Mitchellville, Prince George’s County.—In the U. S. National Museum are 2 upper teeth, molars or premolars (No. 8813), of a horse found on his estate northwest from the town named, by Mr. Edward S. Walker. They were presented to the National Museum by Dr. Edward W. Berry, of John Hopkins University. These teeth, apparently first and second molars, seem to belong to an undescribed species. The table gives the height of the teeth and dimensions of the grinding-surface in millimeters.

Tooth.Height.Length.Width.Protocone.
M17029.52512
M273302314.5

The teeth present the appearance of having been little worn. Measurements of the crown taken about one-third the distance to the base are as follows:

Tooth.Length.Width.Protocone.
M1252511
M22625.213