1914] The Ottawa Naturalist. 13 



ON A NEW GENUS AND SPECIES OF CARNIVOROUS 



DINOSAUR FROM THE BELLY RIVER FORMATION 



OF ALBERTA, WITH A DESCRIPTION OF THE 



SKULL OF STEPHANOSAURUS MARGINATUS 



FROM THE SAME HORIZON.* 



By Lawrence M. Lambe, F.G.S., F.R.S.C., F.G.S.A., 

 Vertebrate Palaeontologist to the Geological Survey, Canada. 



The osteological characters of one of the carnivorous dino- 

 saurs of the Cretaceous are revealed in a wonderful manner by 

 a nearly complete skeleton obtained last summer by the 

 Vertebrate Palaeontological expedition of the Geological Survey of 

 Canada to Red Deer river, Alberta, where a magnificent collection 

 of dinosaurian and other reptilian remains was obtained from 

 the Belly River formation. The expedition was in charge of Mr. 

 Charles H. Sternberg, and this skeleton was discovered by his 

 son, Charles M. Sternberg, 3h miles below the mouth of Berry 

 creek (Steveville), on the south side of Red Deer river, near the 

 prairie level. 



The specimen includes the head, the greater part of the 

 vertebral column, the pectoral and pelvic arches, one at least of 

 the fore-limbs complete, both hind-limbs also complete, the 

 ribs, and apparently the entire series of abdominal ribs. 

 The cervical vertebrae appear to be missing, but as all 

 of the sandstone matrix has not yet been removed, they, or some 

 of them, as well as the other fore-limb, may yet be uncovered. 

 The extreme end of the tail, back of the twenty-second caudal 

 vertebra, was not found. 



The mandible is present and all of the teeth, both upper 

 and lower, are in place, giving the complete dentition. The 

 writer has already pubhshed a short description of the fore-limb,** 

 which has not hitherto been known in any of the Cretaceous 

 carnivorous dinosaurs. Nor has a complete series of ventral 

 ribs in any of these reptiles previously been discovered. 



For the undescribed genus of Theropodous dinosaur, brought 

 to light by this magnificent specimen, the name Gorgosaurus is 

 proposed. The species may be called lihratus in reference to the 

 animal's probable well-balanced and easy gait. 



Gorgosaurus libratus, gen. et sp. nov. 



Carnivorous dinosaur of large size, reaching a length of 

 about twentv-nine feet; head narrow and moderately elongate; 



* Communicated by permission of the Director of the Geological Survey. 

 **The Ottawa Naturalist, Vol. XXVII, No. 10, January, 1914. 



