182 PROCEEDINGS OF THE ACADEMY OF 



horse in the pliocene deposit of Darlington, South-Carolina ; in Richland Dis- 

 trict of the same State; in Skidaway Island, Georgia, and on the banks of the 

 Potomac river. He further observes that he obtained the tooth of a horse, 

 from eocene marl, in the Ashley river, South Carolina, but the researches of 

 Prof. Holmes* indubitably indicate the specimen to have been an accidental 

 occupant of the formation. 



" Specimens of isolated teeth, and a few bones of the horse, from the post- 

 pliocene and recent deposits of this country, have frequently been submitted 

 to my inspection. Many of these I have unhesitatingly pronounced to be relics 

 of the domestic horse, though I feel persuaded that many remains of an extinct 

 species are undistinguishable from the recent one. 



" Whether more than one extinct species is indicated among the numerous 

 specimens of teeth I have had the opportunity of examining, I have been un- 

 able satisfactorily to determine. The specimens present so much difference in 

 condition of preservation, or change in structure ; so much variation in size, 

 from that of the more ordinary horse to the largest English dray horse; and 

 such variableness in constitution, from that of the recent horse to the most 

 complex condition belonging to any extinct species described, that it would be 

 about as easy to indicate a half dozen species as it would two. 



Under the circumstances,! would characterize the extinct horse of the United 

 States as having had about the same size as the recent one, ranging from the 

 more ordinary varieties to the English dray horse, with molar teeth, frequently 

 comparatively simple in construction, but with a strong disposition to become 

 complex. 



" Among the number of teeth of the horse in Prof. Holmes' collection labelled 

 as coming from the post-pliocene deposit of Ashley River, there are several, 

 which, from their size, construction and condition of preservation, I feel con- 

 vinced are of recent date : and these no doubt became mingled with the true 

 fossils of that formation where it is exposed on the Ashley River, in which 

 position I personally found undoubted remains of the recent horse and other 

 domestic animals, and objects of human art, mingled with remains of fishes, 

 reptiles, and mammals, washed by the river from the banks, composed of eocene 

 and post-pliocene deposits. 



" Teeth of an extinct species of horse, however, undoubtedly belong as true 

 fossils to the post-pliocene formations in the vicinity of Charleston. These 

 are usually hard in texture, stained brown or black from the infiltration of ox- 

 ide of iron, sometimes well preserved, but more frequently in a fragmentary 

 condition and water-worn. Generally they are not larger than the teeth of the 

 more ordinary varieties of the domestic horse, and sometimes are quite as simple 

 in the plication of their enamel, but usually are more complex and sometimes 

 exceedingly so. 



" Figure 1 represents a first superior molar tooth, neither larger nor more 

 complex in structure than the corresponding tooth of the recent Horse. This 

 specimen, which is dense and jet black in color, was obtained by Prof. Holmes 

 from a stratum of ferruginous sand, two inches thick, exposed on the side of a 

 bluff, on Goose Creek, about twelve miles from Charleston. 



" Having expressed a desire to see the locality from which the tooth just 

 mentioned was obtained, Prof. Holmes afforded me the opportunity of doing so. 

 The bluff is about thirty feet high ; its base is formed of a pliocene limestone, 

 about fifteen feet thick, and composed of the debris of marine shells : above 

 this is the stratum of ferruginous sand, of post-pliocene age, containing nu- 

 merous pebbles and rolled fragments of bone all blackened like the tooth ob- 

 tained from the same positios. Overlying the latter stratum, there is a layer 

 of stiff blue clay, about two feet in thickness, and above this there are about 

 twelve feet of sand and earth-mould. 



* Ibidem, 68. 



[July, 



