[lambe] progress of VERTEBRATE PALEONTOLOGY . 25 



Upper Jurassic (Wealden) of England. The differences to be found 

 in the shape and marginal sculpture of the teeth afford some of the 

 most reliable data by which these species may be distinguished. 

 Cionoden stenopsis, described by Cope from this horizon in Assiniboia, 

 is very imperfectly known from small fragments of the jaw. Although, 

 in his original description. Cope mentions that parts of teeth were 

 preserved with the jaw-fragments, no trace of the , former are now 

 with the type material in the museum of the Geological Survey. 



Trobdon formosus has been provisionally referred to the Lacertilia; 

 it is known from teeth alone. Belonging also to the Squamata, of the 

 suborder Ensucliia, are the two crocodiles Crocodilus humilus, named 

 from numerous teeth, and BoUosaurus perrugosus, of which the 

 lower jaw and the brain case are now known. This completes the lisit 

 of reptiles. 



The earliest mammalian remains, and the only Cretaceous ones, 

 so far collected in this country, have been named Ptilodus primœvtis and 

 Boreodon matutinus, and are from the Eed Deer river. P. primœvus 

 is a multituberculate mammal more primitive than the Laramie Pla- 

 giaulacids, and is the earliest known species of the genus. The writer 

 succeeded in obtaining a tolerably complete right mandibular ramus, 

 in iwhich are preserved the fourth premolar and the first molar. 

 The teeth present characters that seem to indicate an approach to the 

 Laramie Cretaceous genus Meniscoëssus. Boreodon is founded on a 

 single tooth having a well-developed cingulum and two roots. Mr. 

 Hatcher, of the Carnegie Museum, Pittsburgh, was fortunate enough 

 during the summer of 1903 to find, in rocks of this horizon, a mandi- 

 bular ramus, which he considers to belong to this species. He is of the 

 opinion that the animal will prove to be a marsupial. A description 

 of this additional material would be of interest. 



As regards the fauna of the Belly Eiver series as a whole it is 

 decidedly archaic in character as compared with that of the Laramie, 

 it includes specialized types that have survived from Jurassic times and 

 groups in stages of evolution more primitive than their Laramie repre- 

 sentatives. Attention is called to the absence of Sauropoda, a group 

 almost confined to the Jurassic. 



10. Cretaceous fauna. Nanaimo group. — The Xanaimo group 

 of the Cretaceous as developed in Vancouver island, has yielded as yet 

 few vertebrate fossils. A tooth of the Selachian, Lamna appendiciilata 

 of the suborder Asterospondyli, is from this horizon. Asterospondylic 

 vertebrae thought to belong to the Carchariidae, as well as vertebrœ of a 

 Hemibranch of the family of Dercetidse, also occur in these rocks. 



