FOSSIL SQUALID^ OF THE UNITED STATES. 145 



" Th: Jefferson presents his thanks to dr. Reid for the curious fossil teeth he has 

 been so kind as to forward to him, and which have been safely received, he will 

 immediately send them to the Philosophical Society at Philadelphia, which is the 

 best disposition he can make of them for obtaining satisfactory enquiry into their 

 character and origin, he prays dr. Read to accept his salutations and assurances of 

 respect. 



Washington, Feb. 23, '06." 



2. C. ANGUSTiDENS, Agassiz. Figs. 10 to 38. Professor Agassiz has decided to 

 refer to this species several which he has described by other names, and among them 

 C. lanceolatus, C. heterodon, C. megalotis, C. auriculatus, C. iurgidus, C. semi-serratus, 

 and C. toUapicus. At the time his descriptions were given he had seen but few 

 specimens, and rather hastily decided upon characters which subsequent experience 

 and the examination of many specimens induce him to refer to one species. My 

 collection contains a very full series of individuals of many varieties of form of 

 C. angustidens. Figures are given of them all. While C. megalodon is broad and 

 flat, this species is more lanciform and narrower — the former is destitute of lateral 

 winglets while this is characterized by them well developed on both sides — in some 

 specimens distinctly separate from the principal cone, while in others placed on the 

 same base, the enamel being continuous over both at the radicle. In nearly all the 

 individuals the crown is perpendicular, occasionally tending slightly inwards but 

 oftener outwards. The bodies are arched on the inner surface, flat outwardly, and 

 are covered with a dense firm enamel, usually preserving a beautiful polish, the apex 

 is more or less acute and the edges indented with well marked serratures, which in 

 the winglets are so prominent as to make them appear often as if separated into 

 several. In the larger specimens the root is thick and prominent on the inner face 

 and somewhat concave on the outer, its branches are generally symmetrical. In old 

 teeth there is an interspace void of enamel next the root on the inner face, while on 

 the outer the enamel extends to the root. 



Figs. 10, 11, 12, represent what Agassiz described as C. angustidens; figs. 13, 14, 

 15, 16, C. turgidus ; figs. 17, 18, C. toUapicus ; figs. 19, 20, 21, 22, 23, C. lanceolatus; 

 figs. 24, 25, 26, 27, 28, 29, C. megalotis; figs. 30, 31, 32, C. heterodon; figs. 33, 34, 

 35, 36, are lateral teeth resembling C. semi-serratus ; figs. 37 and 38, are probably 

 lateral teeth of an old individual from their greater thickness, and of the variet}^ 

 C. heterodon. 



Most of my specimens are from the Eocene of South Carolina. Fig. 12 is from the 

 White limestone (Eocene) of Alabama, and fig. 13 from the same deposit in Wayne 

 county, Mississippi. For these specimens I am indebted to C. S. Hale, Esq., of 

 Mobile. The largest variety in my cabinet is from the Eocene Green sand of Santee, 



