1869.] HUXLEY MEQALOSAURUS. 311 



Much difficulty was experienced in extricating the remains unin- 

 jured, for the coal beneath had yet to be worked. The greater 

 portion was ultimately removed in a fair state of preservation, 

 owing to the persevering attention of William Firth, a miner 

 whose zeal was stimulated by some knowledge of geology and in 

 particular of coal fossils. 



The shale which forms the roof of the Black-Bed Coal has long 

 been known to collectors as a repository of interesting and well- 

 preserved fish-remains. 



The Black-Bed Coal is in the middle division of the Yorkshire 

 Coal-field, lying about 40 yards above the Better-Bed Coal, and 

 separated by about 220 yards from the Halifax Coals, which are 

 the lowest workable seams. The exact horizon of important fossils 

 is, perhaps, worth noting, though within the Coal-measures no true 

 vertical limits of species are known to exist. 



Judging from a cursory survey of several public and private col- 

 lections, I am inclined to think that the remains of various in- 

 teresting Carboniferous Batrachians are still unrecognized as such, 

 and taken by their possessors for parts of fishes. When we are in 

 a position to make a correct estimate, it will probably be found 

 that the Batrachia of the Coal-measures are not only specifically 

 numerous but individually abundant. 



EXPLANATION OF PLATE XL 



(All the figures are of the natural size.) 



Fig. 1. Part of the upper jaw with teeth of Pholiderpeton scutigerum. 



Figs. 2, 3, 4, 5. Scutes from various parts of the body. 



Fig. 6. Front view, and Fig. 7, side view, of a detached vertebra : «, remains of 

 the transverse process ; h, the praezygapophyses ; c, the posterior face 

 of the centrum, the inferior moiety of which is broken away. 



DlSCFSSION. 



Mr. Salter observed that, of both plants and mollusks, it ap- 

 peared to him that there were some which were eminently charac- 

 teristic of different horizons in the Coal-measures, and which were 

 to be traced over large areas. It was possible that the same might 

 prove to be true with regard to vertebrate animals. 



Dr. Duncan called attention to the conditions of life necessary for 

 such an animal, which could not have been in accordance with the 

 commonly received views of the character of the Carboniferous period. 



6. On the Uppee, Jaw of Megalosaurus. By T. H. Huxley, LL.D., 

 F.R,S., President of the Geological Society. 



(Plate XII.) 



As all who have paid attention to the Dinosauria are aware, our 

 knowledge of the structure of the skull in these extinct reptiles is 

 very defective. This is particularly true of Megalosaurus, of which, 

 up to the present time, only a portion of the lower jaw has been 

 known. I am therefore very glad to be enabled, by the kindness of 



