REPTILIA OF KIRTLAND FORMATION GILMORE 185 



As pointed out by Hay (1908, pp. 496-497), A. vorax differs from 

 A. fordanus and A. austerus in having the anterior border of the 

 nuchal beveled instead of clipped off at right angles to the upper 

 surface. The form of the outer end of the first costal also serves to 

 distinguish vorax from austei^s. 



U.S.N.M. no. 6550, referred to in a previous paper (Gilmore, 1916) 

 as questionably identified by Hay as Aspideretes vorax, can now 

 quite certainly be dismissed from furtlier consideration in that con- 

 nection. The thinner nuchal and different shape of the first costal, 

 which does not participate in the formation of the anterior border 

 of the carapace, appear sufficient to exclude it from this species. 



Class PISCES 

 Family SQUATINIDAE 



Figure 17 



The family of angelfishes, or monkfishes, appears to be represented 

 in the Kirtland formation by a single tooth (fig, 17) found asso- 

 ciated with scales of Lepisostcus and teeth of Miiledapkus in SWy^, 

 T. 24 N., R. 13 W., San Juan County, N. Mex. The tooth has a 

 conical crown without lateral denticles Avith a de- 

 jDressed root, much of which is missing. If this 

 identification is correct, the specimen is of interest 

 as being the first representative of the Squatinidae 

 to be found in the Cretaceous of North America. 



FIGUUE 1 I . 



Tooth of 

 THE KIRTLAND FAUNA AND ITS GEOLOGICAL AGE s q u a t i n i d. 



U.S.N.M. no. 

 13655. Inter- 

 nal view 



Owing to increased activity in collecting, our 

 knowledge of the Kirtland fauna has been greatly twIw natural 

 advanced during the past few years. This work has ^'^^" 

 resulted in the discovery of new forms and also in the recovery of 

 well-preserved specimens of species previously known only from 

 meager materials. These specimens permit of a better diagnosis 

 than was previously possible, resulting in a more accurate estima- 

 tion of the faunal stage represented by the Kirtland formation. 

 The revised faunal list is as follows : 



DiNOSAURIA : 



Hadrosaiiridae : 



Kritosanrus navajovius Brown. 



Parasauroioplius tubiceri Wimaii. 

 Ceiatopsidae : 



Pcntaoeratops sternbergU Osborn. 



Pentaceratops fenestratus Wiman. 



Chastuosaurus sp. 



