1866.] HUXLEY SOUTH AFKICAN DIlfOSAUKIA. 5 



condyles are separated in front by a broad but well-marked groove, 

 the outer boundary of which is formed by a prominent ridge, 

 separating the front face of the bone from the flattened outer 

 face, which is disposed at right angles to the front face. The 

 outer condyle, in which this ridge ends, is narrower than the 

 inner, and projects further forward, but to a less distance back- 

 ward. A very deep groove separates it from the inner condyle. 

 The posterior surface of this condyle forms a stout projecting ridge, 

 which runs up the length of what remains of the shaft of the bone, 

 gradually diminishing in height. The tibial, or inner, surface of the 

 inner condyle slopes obliquely inwards and backwards, as in the 

 femora of Iguanodon and Megcdosaurus. 



I cannot identify this fragment with any part of a reptilian ske- 

 leton but the distal end of a femur ; and if this interpretation be 

 correct, it must belong to some other animal than Euskelesaurus, so 

 much of the commencement of the distal expansion of the femur of 

 the latter reptile remaining as to suflice to prove that it could not 

 have had the peculiar form presented by the present specimen. Pro- 

 visionally, and while awaiting further materials, I shall apply the 

 title of Orosaurus to the fossil reptile indicated by the femur. 

 Of course, the existence of a second great Dinosaurian in the Storm- 

 berg rocks renders it, for the present, impossible to assign the tibial 

 fragments to the one genus or to the other. 



The Stormberg mountains form part of a long range which stretches 

 north-eastward for several hundred miles, and takes the name of the 

 Drakenberg on the north-west frontier of Natal. In Mr. Bain's 

 map and sections illustrative of the geology of South Africa, pub- 

 lished in the seventh volume of the Transactions of this Society, this 

 range of mountains is seen to be formed by the southern edge of a 

 considerable thickness of horizontal strata, piled conformably above 

 the Karoo-beds, which have yielded the Dicynodonts and so many 

 other remarkable true reptiles and Labyrinthodonts. 



According to Mr. Bain, " these Stormberg beds," as they might be 

 called, contain reptilian and vegetable remains ; but I know of no 

 description of any of these except that given by Professor Owen of 

 certain fossil remains, discovered by Messrs. Orpen in the Draken- 

 berg, 250 miles from the Stormberg, which Professor Owen has called 

 Massospondylus, PacJiyspondylus, and Leptospondylus, and which he 

 considers to "indicate three or more genera or species of large extinct 

 carnivorous reptiles, combining in their vertebrae and bones of the 

 extremities both Crocodilian and Lacertian characters, with an indi- 

 cation of a structure of the sacrum like that in the Dinosauria. 

 Their precise place in the Reptilian class cannot be determined until 

 the cranial and dental characters are known"*. 



I have carefully examined these fossil bones, which appertained 

 to animals of much smaller dimensions than EusJcelesaurus, and, so 

 far as they are comparable, differ from the latter. 



^ Descriptive Catalogue of the fossil organic remains of EeptiHa and Pisces 

 contained in the Museum of the Eoyal College of Surgeons of England (1854). 



