98 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894, 



volcanic series. On this occasion, although Blake continued to 

 maintain his unconformable overlap, he does not appear to have had 

 any supporter. Dr. Hicks even went so far as to assert that the 

 Caer Caradoc volcanic group had constituted a source of supply for 

 the Longmynd series, in which there were no indications of volcanic 

 rocks. At that time he saw no reason for separating the Long- 

 mynds from the Cambrian. It may be that he has modified his 

 opinion, since it has been shown that the Cowley Sandstone, which 

 is the associate of the quartzite, contains the oldest-known Cambrian 

 fauna, and must therefore be very near the base. This would seem 

 to leave but little room in the Cambrian system for the Longmynd 

 rocks, which may be regarded for the present as occupying a high 

 position in the Fundamental Rocks, somewhat analogous to those of 

 Howth and Bray Head, though not of necessity occupying precisely 

 the same horizon. 



Once more we find Prof. Blake busy with the unfossiliferous sedi- 

 mentary series, and this time with the rocks mapped as Cambrian in 

 Caernarvonshire. In his first contribution to this very thorny sub- 

 ject, written some years ago, the Author alludes to the triangular 

 duel which had for some time been going on between Messrs. Hicks 

 and Hughes, as representing the most uncompromising pre-Cam- 

 brianism, of the one part, Prof. Bonney of the second part, and the 

 officers of the Survey, as defenders of Ramsay, of the third part. 

 Not that Prof. Hughes and Dr. Hicks have been at all times agreed 

 in their respective interpretations of this troublesome district, nor 

 that the officers of the Survey have undertaken to maintain the 

 views of Sir Andrew Ramsay in their entirety. The Author tells us 

 that he was led to study the area from its relations to the rocks of 

 Anglesey, with the result that the evidence on the ground is not 

 sufficient to justify the conclusion that pre-Cambrian rocks can be 

 said to occur, although, in his map, the igneous mass between Caer- 

 narvon and Bangor is represented as pre-Cambrian of two distinct 

 types. In his opinion the views of the Survey, except as regards 

 metamorphism, most nearly approximated to the natural interpre- 

 tation of the facts that were known at the time, although new facts 

 now necessitate a modification. 



He altogether disputed the notion of a basal Cambrian conglome- 

 rate in North Wales, alleging that in the Bangor and Caernarvon 

 area three different conglomerates had been confounded. He further 

 alleged that the only conglomerate in the district which showed 

 distinct unconformity upon the underlying rock was of Arenig age. 





