ART. 35 MASTODONS FOUND IN TEXAS HAY 13 



also that the cross-section of the tusk is different from that of 

 G. productum. It is quite different, too, from that of G. angustidenSj 

 as figured by Schlesinger ^* It resembles more closely the section of 

 lower tusk figured by Cope in his descriptoin of G. froductum^^ 

 but is yet different. The long diameter is 49 mm., the shorter one 37 

 mm. There is a faint groove or channel on the lower side and a 

 similarly faint one on each side of the prominent upper ridge. 



In the collection are parts of two tusks of a young specimen sup- 

 posed to belong to the same species as did the adult remains. The 

 larger piece, now 90 mm., must have been still longer, since no pulp 

 cavity is present. The cross-section is broadly oval, without any 

 ridge or channel. As in other cases, the narrow end of the oval is 

 taken to be away from the midline of the jaw. The rear part of the 

 fragment is yet covered with the thin coat of cement. Where this 

 is removed the surface is traversed by narrow parallel ridges and 

 grooves. At the distal end of these tusks are distinct evidences that 

 they were useful instruments. Figure 5 of plate 4 shows these 

 fragments of tusks as seen from above and of the natural size. It 

 will be noted that each has a large worn and polished surface 35 mm. 

 long. On the underside (fig. 6) is another polished surface not quite 

 so large. On the outer border the two surfaces round into each 

 other. On the face next to its fellow the tusk of the right side has 

 a flat worn surface 18 mm. long, not seen in the figure, as if it had 

 worked in contact with the other one, but this other shows no indi- 

 cations of any such friction. This worn surface is crossed by about 

 14 grooves. The ridges between these are possibly the outcropping 

 edges of the layers of ivory, but this is uncertain. 



5. Identity of the Navasota mastodon 



The writer refers the Navasota remains here described to Cope's 

 form which he named Tetrahelodon serridens ci?narrcmis.^^ It is 

 therefore to be known as Gomphotherium cimarronis (Cope). Ac- 

 cording to Osborn,^'^ this was found in the Upper Miocene near 

 Clarendon, Texas. The type is a tooth said by Cope to be the left 

 lower last molar. To the writer the tooth has greatly the appear- 

 ance of being the left upper tooth. Possibly the arrangement of 

 the anterior fangs of the root might decide the matter. The 

 fact that there is in the type a cingulum called external appears 

 to show that the tooth is an upper one,^^ The upper hinder 



" Denkschr. Natui"li. Staatsmus., Vieuna, vol. 1, pi. 1, fig. 5. 



15 Wheeler's Surv., vol. 4, pi. 71, fig. 8. 



10 Vert. Palaeont. Llano Estaeado, 1893, pp. 18-20, pi. 3, flgs. 1, 2. 



" Amer. Miis. Novitates, No. 1, p. &. 



1* Cope, Wheelei-'s Surv., vol. 4, p. 19. 



