MORPHOLOGICAL REVISION 89 



clay is 37 feet thick and the fossils were found 4 feet above the base of the clay. 

 Three feet above the base of the clay there is a layer of nodular limestone, and the 

 teeth were found lying on this layer where it projects from A\ _j«». 



the bank on the roadside. The other bones were all em- / \ £\ c^_5 £^ V 

 bedded in the clay, about one foot above the limestone *~"^l b c d» 

 * * *. On the Pittsburgh Shale rests the Ames Limestone, f**\ /^ ==e ^ >%a:s *\ 



the youngest of the marine limestones in the region. It L. \^\ \ . - J 



is almost exactly in the middle of the Conemaugh series. e 7 ' f 



It is 315 feet below the base of the Pittsburgh Coal, and Fig. 34. — Outline drawings of several 

 695 feet below the base of the Dunkard series (Permian). %Z^£t3X»£ 

 The Ames Limestone is about 300 feet above the Freeport saurus;c,Deimatodon;d,c,f,Dia- 

 Coal (top of the Alleghany series)." **"■ 



This is the lowest known horizon for reptiles except the locality of Linton, 

 Jefferson County, Ohio (from which was described Isodectes Cope and Eosauravus 

 Case), which is of Alleghany age. 



Bolosaurus striatus Cope. (Plate 7, figs. 4, 5, 6.) 



Characteristic specimens: Two skulls (Nos. 4685 and 4686) and several vertebrae 

 (No. 4686) Am. Mus. Nat. Hist. A jaw, No. 4321 Am. Mus. Nat. Hist. Cope Coll. 



The two skulls are in a good state of preservation except that one has been 

 crushed from side to side and the other from above downward. I quote from a 

 previous description (16): 



"Unfortunately both specimens have been so injured in the temporal region 

 that it is impossible to make out the limits of the individual bones, but there is no 

 doubt that there was a complete roof without trace of temporal vacuities. 



"The skull (fig. 33, B and C) was roughly triangular in form, wider and higher 

 posteriorly, and terminating in a blunt snout anteriorly. The interorbital space 

 is moderately wide and slightly concave or flat and is pierced by a fair-sized parietal 

 foramen. The facial portion of the skull seems to have been rather sharply rounded 

 above. The anterior end of the skull is so injured that it is not possible to determine 

 the exact position of the nares, but they were nearly terminal and apparently looked 

 outward rather than forward. The orbits are large and were nearly circular in 

 outline; the anteroposterior diameter is nearly equal to the preorbital length of the 

 skull. The edges of the orbit are prominent above and anteriorly, but are less so 

 below; there is no pit in the prefrontal, such as is so characteristic of the Pelycosauria. 



"From the condition of the specimen it is impossible to make out the shape or 

 relations of all the bones, but it is evident that their surface was smooth and free 

 from sculpture except along the anterior edge of the orbit. 



"The maxillary is rather elevated with a convex superior edge and a nearly 

 straight alveolar edge; posteriorly it extends almost to the back of the orbit but is 

 prevented from taking any part in it by the jugal which overlies the posterior fourth. 

 There are 16 counted teeth in the best-preserved specimen, which is evidently a 

 nearly perfect premaxillary and maxillary series. The anterior three teeth, which 

 probably belong to the premaxillary, are larger than the anterior maxillaries and 

 probably functioned as incisors. In common with the anterior maxillaries they are 

 simple cones with large pulp cavities. Beginning with the sixth tooth, the maxillary 

 series increases in size to the tenth or eleventh, and then decreases in size to the 

 posterior end; the last two are abruptly smaller and are only minute cones. The 

 teeth from the sixth to the fourteenth show the characters of the family and genus. 

 They are transversely expanded, much as in the Dtadectidce, but in a less degree, 

 and on the outer edge there is a prominent cusp which descends considerably below 



