NOTES ON CARBONIFEROUS COCHLIODONTS 29 



how they came to be described as two distinct species from scanty 

 material. 



Eastman says 1 he is convinced that "the teeth figured as 

 Deltodus complanatus in the posthumous paper of Newberry are 

 fragments of D. occidentalis." These specimens are now preserved 

 in the collection of Walker Museum, and as two of them are practically 

 complete, there is no reason why Newberry should have identified 

 them incorrectly, and with the union of the two species both Newberry 

 and Eastman are correct in their conclusions. 



Formation and locality: Kinderhook, Burlington, and Keokuk limestones; 

 Iowa, Illinois, and Indiana. 



Sandalodus emarginatus sp. nov. 



(Plate II, Figs. 1,2 and 3) 



A very large species. The dimensions of the type specimen are: 95 mm along 

 the antero-lateral border, 65™™ along the inner end, no mm along the postero- 

 lateral border, 26 mm in thickness at the thickest part. Strongly arched longi- 

 tudinally and transversely. Alation strong, extending out 40™™ from the postero- 

 lateral border. At the place where this alation diverges from the main part of 

 the tooth there is a strong notch which extends to the middle of the alation in a 

 line parallel with the main axis of the tooth. The anterior border of the alation 

 is gently convex to near the outer angle, where it is strongly convex. The alation 

 is thick and strong, does not turn up at the outer angle, and has a sharp ridge 

 extending from the outer angle to the middle of its base, the sharpness of this 

 ridge being due to the worn condition of the tooth near the inner border. Rings 

 of growth show faintly on this worn surface. Inner end of tooth gently convex 

 near the antero-lateral border, gently concave near the postero-lateral border. 

 Inner posterior angle slightly obtuse. Outer end curved abruptly downward, 

 and probably wottnd once and a half on itself as in Sandalodus laevissimus. 



S. emarginatus differs from S. laevissimus in being more strongly 

 arched both transversely and longitudinally, in being thicker and 

 stronger, in having a strong notch where the alation diverges from 

 the main part of the tooth, and in the alation being thick, convex 

 upward, and not turning up at the point : 



The types of S. emarginatus are two specimens, one of which is 

 almost perfect, only a small part of the initial coil being absent; the 

 other has lost part of the initial coil and half of the alation. 



Formation and locality: Keokuk limestone; Keokuk, Iowa. 

 Paleontological Collection, Walker Museum, No. 10059. 



1 Op. cit., 1903, p. 19S. 



