8 



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 unable satisfactorily to deter. nine. 

 The specimens present so much difference in condition of preser- 

 vation, or change in structure; so much variation in sizt, 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 indi- 

 cate a half dozen species as it would two. 



Under the circumstances, I 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 compara- 

 tively 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-pleiocene deposit of 

 Ashley River, there are several, which, from their size, construc- 

 tion and condition of preservation, I feel convinced 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 re- 

 cent 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-pleiocene deposits. 



" Teeth of an extinct species of Horse, however, undoubtedly 

 belong as true fossils to the post-pleiocene formations in the 

 vicinity of Charleston. These are usually hard in texture, 

 stained brown or black from the infiltration of oxide ot 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 exceed- 

 ingly 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; 



