BUDLEIGH-SALTERTON PEBBLE-BED. 325 



2. The assumed British Silurian source ; 



3. The supposed Normandy and Brittany source ; 



4. The assumed mid-Channel source ; 



and afterwards sum up the conclusions that may be derived from any facts that may have 

 been brought to bear on the subject. 



1. The supposed British Devonian Source of Derivation. 



Although we have in Devonshire and in Cornwall Devonian Sandstones, in none of 

 the rocks of those counties have I found the assemblage of species that occur in the 

 pebbles; and, if we except Sp. Vcrneuilii and three or four more, the greater bulk of the 

 species are not known to occur in British Devonian rocks. The Hangman Grits in 

 particular contain, according to Mr. R. H. Valpy, 1 no Brachiopoda and, independent 

 of their fossils, they have a very marked lithological character or facies quite different from 

 that of the pebbles. At p. 20 of the new edition of Mr. Valpy's ' Notes on the Geology 

 of Ilfracombe and its Neighbourhood ' it is stated in a foot-note : " Writing now, in 

 1880, there seems no doubt that the Stringocephalm bed is above the Hangman 

 Grits ;" and in a letter, dated 20th August, 1880, Mr. Valpy writes me: "The Stringo- 

 cephalus bed seems above those grits, and seems, indeed, the basement of the Ilfracombe 

 group, if that group is to be severed from the Hangman beds ; this, however, seems sub 

 judice. Owing to the very hard and impracticable nature of the matrix, it is very 

 difficult to obtain an example of the fossil. I was therefore led into error when I stated 

 in my paper in the ' Geological Magazine' for August, 1880, that the Hangman Grits 

 contain very few Brachiopoda besides Stringocephalus Burtini, but was correct when I 

 said that that species has not been hitherto found in the Budleigh-Salterton pebbles." 

 In a letter I received from Mr. Pengelly on the 13th of September, 1879, that dis- 

 tinguished Devonshire geologist says : " I never thought the hypothesis of the Hangman 

 as a source of the pebbles was worth a second thought." Major A. Wyatt-Edgell writes 

 me on the 26th of August, 1879 : "Erom the Hangman of North Devon I have never 

 seen anything I could mistake for a Budleigh-Salterton fossil." The same view is 

 expressed to me by Mr. Townshend Hall, who has made so close a study of North- 

 Devon rocks and fossils. 



Having communicated on the subject with Mr. A. E. Ussher, he writes me on the 

 30th November, 1879 : "Any one knowing anything about the relations of the Trias of 

 Devon must be aware that such a derivation from North Devon is quite impossible. If 

 the Hangman beds are to be found, or their representatives, in South Devon and 



1 'Not?s on the Geology of Ilfracombe,' &c. At p. 23 of this Guide Mr. Valpy quotes from the 

 Hangman Grits the following fossils: — Bellerophon, Cucvllcea, Euomphalus, llacrocheiliis, Myalina, 

 Mytilus, Natica, Pleurotomaria, Sanguinolaria, Solen, with two Corals, and a Fenestella. 



43 



