124 Revieics — Dollo's Dinosaiiria of Bernissart. 



mineralogical representatives of four of the above eight families — 

 the granites, syenites, el^olite-syenites, and diorites. They exhibit 

 three types of structure : the granitic, met with only in the most 

 acidic rocks (Aplite, which is thus removed from the granites) ; the 

 granite-porphyritic, divided mineralogically into granite-porphyry, 

 syenite-porphyry, elgeolite-syenite-porphyry, and diorite-porphyrite ; 

 and the lampropliyric, including syenitic and dioritic families only. 

 The lamprophyres, as that name is used by the author, are either 

 panidiomorphic-granular or holocrystalline-porphyritic in structure. 

 The syenitic lamprophyres comprise Minette and Vosgesite, the latter 

 name being given to those members which contain hornblende or 

 augite in place of biotite ; similarly the dioritic family divides into 

 Kersantite and Camptonite. 



The characteristic structure of the volcanic rocks is the porphyritic, 

 which is classified under various types according to the nature of the 

 ground-mass. The palaeo-volcanic rocks are ranged under five 

 families: quartz - porphyries, quartzless - porphyries, porphyrites, 

 augite-porphyrites and melaphyres, and picrite-porphyrites ; of 

 which only the first is treated in the part of the work already 

 issued. The discussion of the essential nature of the ground-mass 

 in the quartz-porphyries and the section devoted to the classification 

 and structure of these rocks have been rendered fuller, but little is 

 said on the subject of secondary devitrification. The artificiality 

 of the separation of palseo- and neo-volcanic rocks is sometimes 

 apparent, as for instance in the description of the Arran pitchstones 

 on p. 407. 



Professor Rosenbusch's treatise seems to be a real step towards 

 a true natural classification of rocks, and perhaps we may even be 

 sanguine enough to hope that it will afford a basis for a uniform 

 system of nomenclature in petrological writings. A. H. 



II. — M. DoLLo's Notes on the Dinosaurian Fauna of Bernissart. 



{Continued from p. 87.) 

 The hind limbs next claim attention. Having insisted on the 

 avian form of the femur, and its divergence from birds in being 

 relatively longer as compared with the tibia, M. Dollo goes on to 

 argue that, whereas the femur is horizontal in birds, its length 

 implies a more inclined or mammalian position in these Dinosaurs. 

 We are unable to appreciate the force of the argument, which might 

 have some weight if the animal were an ordinary quadruped. But, 

 in the first place, the Kangaroo, an animal not entirely beyond com- 

 parison in its proportions, carries the femur at rest in a nearly 

 horizontal position ; and, secondly, by giving the femur this highly 

 inclined position, M. Dollo raises the extremity of the ischium and 

 the chevron bones of the caudal vertebra ofi" the ground to a level 

 with the distal extremity of the tibia. Now, when the skeleton of 

 such an animal as Igiianodon Bernissartensis is examined, the tail, 

 unlike the tail of a Kangaroo, is seen to have consisted of dense 

 muscular substance like the tail of a Crocodile, of enormous weight, 

 extending from the extremities of the chevron bones to the 



