170 The Ottawa Naturalist. [November 



separated from that of the Laramie by the presence of higfhly 

 specialized Stegosauria or plated Dinosaurs, by numerous turtles 

 of the Jurassic family PleurosternidcB and by numerous large 

 Plesiosaurs." 



Professor Osborn shows that the Belly River fauna is related 

 to that from the so-called Laramie Cretaceous of the Judith River 

 region in Montana, much more nearly than it is to the typical 

 Laramie of Wyoming, and that there is stratigraphic evidence 

 that a part of these Judith River beds may be considerably older 

 than the true Laramie. He therefore considers that a part of the 

 so-called Laramie vertebrates of Montana are probably of Mid- 

 Cretaceous age. But no certain results can be reached on this 

 point until the stratigraphy is better known. 



The fauna described by Mr. Lambe is chiefly of land and 

 fresh-water groups ; some marine types, however, are present. 

 There are thirty-four species represented, of which nearly half are 

 new to science. Turtles, especially Triotiyx, are very abundant. 

 The Dinosaurs are the largest and most important part of the 

 fauna. The slender, long-limbed and long-tailed, swift-running 

 types are represented by a large species of Ornithominius estimated 

 at 22 feet in length. The most characteristic Dinosaurs are of 

 the Iguanodont or duck-billed, and Ceratopsian or horned groups; 

 these show various primitive features when compared with the 

 corresponding forms in the true Laramie. Stereocephalus is a 

 new genus of Stegosaur or Plated Dinosaur with very massive 

 skull armour and protective bony rings around the neck, which 

 very much sutrgest the tail armature of the Edentate Glyptodon. 

 Two mammals are also described, a rare discovery in any Meso- 

 zoic formation. 



Much credit is due Mr. Lambe for the twenty-one excellent 

 plates with which the work is illustrated. 



W. D. Matthew. 



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