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

The teeth are moderately curved, so that the outer face is convex, the inner concave. Some of the cement is retained and is colored blue with vivianite. The enamel presents less complication than is usually found in either Equus complicatus or E. leidyi. The dimensions of the teeth and the narrowness, especially of the second molar, seem to exclude reference to either of the species mentioned.

4. Chesapeake Beach, Calvert County.—Mr. William Palmer, of the U. S. National Museum, had for many years been making collections, mostly of Miocene vertebrates, along the cliffs at Chesapeake Beach. Among other fossils found there are some remains of horses, among them one much worn upper tooth, probably a premolar. The height is only 21 mm., the length of the grinding-surface 22.4 mm., the width 24 mm. It may be referred provisionally to E. leidyi. Mr. Palmer had also an ungual phalanx and a cervical vertebra and various other bones and teeth of horses. The geological situation at the place and the other Pleistocene species found there will be discussed on pages [347]–[348].

5. Cavetown, Washington County.—In his work on the exploration of Bushy Cavern, near Cavetown, Mr. Charles Peabody (Bull. IV, Dept. Archæol., Phillips Acad., p. 12) stated that in a limestone quarry, south of the cave, in the red earth, was found a tooth which J. W. Gidley identified as probably Equus complicatus. In 1920 (Proc. U. S. Nat. Mus., vol. LVIII, pp. 96–109), the writer described a collection made at Cavetown. In this were other remains referred to Equus complicatus. Some fragments of a large tooth were referred with doubt to Equus giganteus.

6. Corriganville, Allegany County.—In a crevice in a limestone rock, at a point about 3 miles west of north of Cumberland, taken in a straight line, J. W. Gidley, in the fall of 1912, made a large collection of fossil vertebrates. In this collection is a first phalanx of an extinct horse. The species has not been determined. A list of the accompanying species, so far as determined, will be presented on pages [349]–350.