82 



ABNORMAL GEOLOGICAL DEPOSITS IN THE BRISTOL DISTRICT. 



Discussion. 



The President spoke of the great industry and skill of the author 

 in collecting the evidence on which this paper was hased. 



Mr. Tawney stated that Mr. Sanders held that the Dolomitic 

 Conglomerate is of different ages in different parts of the district, 

 and that the Thecodontosaurus is high up in the Keuper series. He 

 thought that the fact of these remains being imbedded in solid con- 

 glomerate was scarcely reconcilable with the notion that they came 

 from vein-infilling. 



Dr. Duncan, with reference to the origin of the so-called Tuhu- 

 tella, stated that similar tubes might be seen in course of formation 

 by the escape of air-bubbles from the surface of oysters and other 

 shells covered with Algse in turbid water containing carbonate of 

 lime. 



Prof. Seeley spoke of the great interest attaching to the question 

 of the age of the Thecodontosaurus. He considered the specimens 

 exhibited to belong to at least two genera. He stated that the ilium 

 of Thecodontosaurus is Crocodilian, with Dinosaurian affinities. 



Rev. H. H. Winwood supported the views of the author concerning 

 the position of the veins of Durdham Down. He remarked upon the 

 difficulty of understanding the mingling of different faunas in the 

 same vein. 



The President supported the views of Mr. W. Sanders, as ex- 

 pounded by Mr. Tawney, and bore testimony to the great value of 

 Mr. Sanders's map of the Bristol area. 



The Author agreed that the Magnesian Conglomerate is of diffe- 

 rent ages. He thought the Thecodontosaurian remains were ob- 

 tained from the top of one of the veins. He stated that, while the 

 veins occasionally contained the remains of fossils belonging to more 

 than one geological period, others contained organisms which 

 appeared special to a single period only, implying a denudation and 

 refilling in veins, at the present time difficult to account for. 



