igo2J Matthew Reviews. 169 



On Vertebrata of the Mid-Cretaceous of the North-West 

 Territory. (i) Distinctive Characters of the Mid- 

 Cretaceous Fauna, by Henry Fairfield Osborn. (2) New 

 Genera and Species from the Belly River Series (Mid- 

 Cretaceous), by Lawrence M. Lambe. 



This important memoir is the second part of the series issued 

 by the Geolog'ical Survey of Canada, in quarto form, containing 

 descriptions of Canadian fossil vertebrata. The first part, pre- 

 pared by the late. Professor Cope, contained descriptions of the 

 Oligocene fauna from the Cypress Hills ; the issue of a con- 

 templated second part on the Vertebrata of the Laramie formation 

 oi the North-west Territory, by the same author, was pre\ ented by 

 his death in 1897. The present memoir contains Mr. Lambe's 

 descriptions of the extensive collections of fossil vertebrata made 

 by him in the Belly River formation in 1897, 1898 and 1901, and 

 an introductory part b}|i Professor Osborn, in which the relations 

 of this fauna to that of the typical Laramie Cretaceous and of the 

 so-called Laramie of Montana is discussed. 



The Belly River series is of Mid-Cretaceous age, as is shown 

 by the stratigraphy. It is overlain by marine strata of the Fort 

 Pierre and Fox Hills groups, and these in turn by the Edmonton 

 fresh-water series of true Laramie age. 



The geological record gives rather scanty information about 

 the inhabitants of the land areas of the Mesozoic. Considerable 

 is known of the land animals of the Trias, and the Upper Jurassic 

 land fauna is large and varied. Then we have a gap, lasting until 

 the end of the Cretaceous, when the equally extensive and varied 

 Laramie fauna appears. The Belly River fauna, of Middle Cre- 

 taceous age, reduces this gap very considerably, and assists 

 greatly in tracing the relationships and lines of descent in the two 

 widely separated faunas of the Upper Jurassic and the Upper 

 Cretaceous. It is much nearer to the Laramie, but some Jurassic 

 groups still survive in highly specialized types, while the groups 

 which belong to the Upper Cretaceous show many archaic charac- 

 ters in this older horizon. It " is distinguished from that of the 

 Upper Jurassic (Como Beds, Purbeckian) by the entire absence of 

 Sauropoda and by the presence of Ceratopsia in great variety. It 

 is affiliated with that of the Jurassic, and so far as we know 



