214 THE KH^TIC ROCKS OP PYLLE HILL, BRISTOL. 



It lias been suggested to me that an account of this local 

 section, which I may mention was visited by a party of the 

 Bristol ]S"aturalists' Society in the summer of 1891, under 

 my guidance, might be of some interest to the members of 

 your Society, whilst it would at the same time give me an 

 opportunity of meeting the objections of my critics to which 

 I have referred. 



You doubtless know that the Rhastic rocks — that interest- 

 ing connecting series between the Trias and the Lias — which 

 are so well developed in the Rhsetiau Alps of Lorabardy, the 

 Grisons and the Tyrol, in this country form a thin, although 

 a remarkably persistent, rock-band, which may be followed 

 diagonally across Eng-land from the Channel, near Lyme 

 Regis, to Redcar on the North Yorkshire coast. Owing to 

 the fact that the Rhsetic rocks in England are not only a 

 thin series, but are also, in the main, of a softish nature, and 

 yield, as a rule, no minerals of economic value, they are not 

 often exposed either in inland scarps or in quarries ; and we 

 have therefore in a general way, to trust to railway-cut- 

 tings, road-cuttings, wells or other similar artificial excava- 

 tions for giving us opportunities for their examination. In 

 the West of England, however, this is not altogether the 

 case, for in this part of the country the Severn has, at several 

 points along its course, carved out splendid sections in these 

 rocks, which not only admirably display their extent and 

 character, but also clearly exhibit their relations with the 

 underlying Trias and the succeeding Liassic rocks. Such are 

 the classical sections exhibited in the cliffs of Westbury-on- 

 Severn, Aust Cliff, Penarth, and Watchet, all of which have 

 at different times received a more or less full and adequate 

 description from one author or another. Inland, however, 

 for the reasons I have already explained, exposures of these 

 rocks are somewhat rare. Thus, when any artificial opening 



