TRIASSIC STRATA OP THE SOUTH-WESTERN COUNTIES. 469 



Warwickshire, to 100 feet. CompariDg these with the lowest di- 

 vision of the Devon and West-Somerset Trias, ranging probably from 

 200 to 1650 feet in thickness, there is fair ground for inferring that 

 it represents the Bunter. 



(Jc) If this be so, it is surely not improbable that the intervening 

 marls and their subjacent passage-beds, representing a thickness 

 varying from 200 to 850 feet, are equivalent to the Muschelkalk of 

 Germany and the " Calcaire coquillien " of France, the difference in 

 character being due to an uninterrupted continuance in Devon and 

 West Somerset of those unfavourable conditions to organic existence 

 which prevailed during the deposition of the Keuper and Bunter 

 sediments. 



Discussion. 



The President called attention to the asserted existence of land 

 in the Devon area, and stated that the investigation which he had 

 once made of the Magnesian Limestone in the north led him to the 

 belief that land must have existed there. 



Mr. Whitaker pointed out that the author had found that in the 

 Devon area the beds thin northward, while Prof. Hull had shown 

 that the beds of the northern area thin to the S.E. He called 

 attention to the discovery of rock like New Red Sandstone in one 

 of the deep borings near London. 



Prof. Bamsay remarked upon the want of illustrative sections, but 

 said that he agreed with Mr. Ussher as to the existence of a barrier 

 near the Bristol Channel, but thought that the strata were in no 

 true sense of the word marine. He also approved of the idea of a 

 gradual overlapping of the Triassic strata, as on the Mendips the 

 upper strata of the Trias were found, the Bunter beds being 

 absent. 



Mr. Johnston-Lavis said that, with regard to the absence of 

 diagram-sections, it was extremely difficult in that district to trace 

 for any distance continuously any subdivision. He thought that 

 on the lake-theory it would be impossible to correlate beds, since 

 they might differ entirely in their lithological composition, although 

 deposited contemporaneously in different areas and in very variable 

 thicknesses. 



Mr. Etheridge said that he had been able to ascertain from 

 specimens in the Penzance Museum that the Budleigh-Salterton 

 pebbles came from Gorran Haven on the southern coast of Cornwall. 

 Similar fossils occur near Torquay and in Staffordshire. Ortliis 

 redux was common among the specimens at Penzance ; and Lingula 

 crumena and several Trilobites also showed that some of the pebbles 

 were derived from Llandovery rocks. These rocks also occurred at 

 Gorran Haven. The Penzance museum also contains fossils singu- 

 larly like those from the Eifel. 



Mr. Whitaker stated that he had himself, on lithological grounds, 

 suggested the Gorran -Haven region as a source for the Budleigh- 

 Salterton pebbles. 



