70 The Ottawa Naturalist. [June 



1 88 1 by Dr. G. M. Dawson in the Willow Creek (Laramie) beds 

 of the Oldman River, Alberta. 



2. No crocodilian remains were found. 



3. Dinosauria — 



a. Most of the dinosaurian bones are thought to belong 

 to TracJwdoii mirabilis. 



In 1 88 1 Mr. T. C. Weston secured fragments of jaw with 

 teeth, of Trachodon mirabilis, ixom. the Laramie of the Red Deer 

 River, and in 1882 Mr. R. G. McConnell obtained a well pre- 

 served femur, from the Laramie of Scabby Butte, Alberta, that 

 appears to belong to the same species. 



h. Other dinosaurian remains from the Laramie of the Red 

 Deer River in the collection of the Survey are a skull oi Lcrlaps 

 ma-assatiis, Cope, found by Mr. J. B. Tyrrell in 1884, and 

 another skull of the same species collected in 1889 by Mr. 

 Weston. 



From a comparison of the reptilian remains from the Belly 

 River beds with those from the Laramie, it would appear that 

 there are three species common to both formations, viz., Plas- 

 tomemis coalescens, Cope, Trac/iodou mirabilis, Leidy, and Lcelaps 

 incrassatus, Cope, also that these are the three forms most 

 abundantly represented in the collection. Remains of P. coales- 

 cens seem to be not uncommon in both formations, those of 

 T. viirabilis are abundant in the Belly River rocks but are not 

 often met with in the Laramie whilst the reverse is the case with 

 those of L. incrassatus. 



The similarity in the vertebrate faunas of the Belly River 

 and Laramie formations suggested by the above comparison is 

 also apparent in the invertebrate faunae of the same formations, 

 from which it may reasonably be inferred that the conditions of 

 life following the deposition of the marine beds of the Pierre 

 were essentially the same as those that preceded it. 



