Vol. 55.] A MEGALOSAUKOID JAW FROM BRIDGEKD. 89 



6. On a Megalosaurotd Jaw from Rh^tic Beds near Bridgend 

 (Glamorganshire). By E. T. Newton, Esq., F.E.S., F.G.S. 

 (Read December 21st, 1898.) 



[Communicated by permission of the Director-General of 

 H.M. Geological Survey.] 



[Plate X.] 



The specimen which forms the subject of the present communica- 

 tion was obtained by Mr. John David, of Porthcawl (Glamorganshire), 

 from a mason, who was engaged in preparing stone for building a 

 wall, at Stormy Down, near Bridgend. It is a block of hard whibish 

 sandstone, which, having been split open, revealed the impression of 

 a reptilian jaw nearly 11 inches long. This fossil was shown to my 

 colleague, Mr. R. H. Tiddeman, who, appreciating the value and 

 interest of so unique a specimen, asked that it might be sent to the 

 Geological Sur^'ey Museum for examination. Mr. David not only 

 acceded to this request, but most generously presented the specimen 

 to the Museum, in order that it might be preserved in a national 

 collection. 



The block of sandstone was one of many which lie on the surface, 

 and undoubtedly represent a bed which has weathered away in the 

 immediate vicinity. Stormy Down is within the boundary of the 

 Penarth or Rh?etic Beds on the old edition of the Geological Survey 

 map ; but whether the bed which yielded the fossil lies above or 

 below the Avicula con^or^a-shales is a point still under investigation. 



A number of internal casts of small lamellibranchs may be seen 

 on the specimen, but they are too imperfect for identification : 

 one of them is an oval shell with the umbo near the anterior third, 

 and is in all probability PuUastra arenicola ; while another, rather 

 larger and of triangular form, may be a Myojjhoria. 



I have received much valued assistance, in the comparison of this 

 reptilian jaw with specimens in the British Museum (Nat. Hist.), 

 from Mr. A. Smith Woodward and Mr. C. W. Andrews ; and I take 

 this opportunity of tendering to those gentlemen my warmest thanks. 



The bony matter of the fossil has disappeared, and thus what 

 remains is a beautifully-preserved mould of the deutary bone of a 

 Megalosauroid reptile with several teeth in place. The impression 

 of the whole of the inner surface and the anterior half of the 

 outer surface have been recovered, but the portion of stone con- 

 taining the mould of the outer surface of the hinder half is wanting. 

 The bone had evidently been much cracked by pressure while still 

 included in the rock, and these cracks are well seen in the casts 

 which have been prepared from the natural moulds. It is upon 

 these casts that the figures and descriptions have been based. 



This dentary bone (PI. X, fig. 1) measures 10*8 inches (275 mm.) 

 in length, 2*6 inches (Q5 mm.) in depth at the hindermost part of 



