356 Prof. Sedgwick mid Mr. Miirchison's Stipplemcntary 



legists present, that lie meant that passage fully to convey the 

 meaning, that we were the first persons who proposed, on the 

 evidence of superposition as well as fossils, that the large tract 

 of Devon and Cornwall (now represented in his map as 

 " Carbonaceous Rocks") should be considered as a distinct 

 physical group belonging to the Carboniferous System; we 

 are on our part anxious, not only to state publicly, that we 

 are satisfied of the entire sincerity of this assui'ance, but also 

 to express (as one of us did at the Geological Society) our 

 deep regret that one or two words were employed in our me- 

 moir which gave pain to our associate. In short, there does 

 not now exist the slightest misunderstanding between Mr. De 

 la Beche and ourselves. 



And next in regard to the Rev. D. Williams, to whom 

 we adverted as putting forth a claim to have been the first 

 to indicate the existence of a trough in Central Devon, we 

 find (having been favoured by him with a sight of the ori- 

 ginal notice which he read at Dublin 1835) that the sole 

 expression which, according to himself, bears upon the point 

 is this : " The argillaceous schist reposes immediately on 

 the granite of Lundy Island, mantling round its south- 

 eastern angle on the one hand and dipping away towards it 

 from the granite of Dartmoor on the other." Mr. Williams 

 indeed allows, that he did not then even mention the word 

 " trough," nor was there, indeed, a single expression in the 

 short notice which could have led any one to suppose that he 

 had then discovered, that two-thirds of the large county of 

 Devon consisted of a great culmiferous basin overlying older 

 strata, still less that this basin was the equivalent of our coal 

 fields. For his observations in that and all his subsequent 

 memoirs (even that just read) go to maintain, that these culm 

 strata are of an age quite distinct from the Carboniferous 

 sera, and form an integral part of the transition series of a 

 much older epoch. 



But in asserting the priority and independence of our own 

 views, and in pointing out how much they diifer from those 

 which Mr. De la Beche, Mr. Williams, or indeed any geolo- 

 gists had previously entertained, we are bound to state, that 



they separated the upper mass of rocks of North Devon which had hitherto 

 been termed grauvvacke from the lower, stated that these rocks rested in 

 a trough-like cavity extending east and west, and concluded that they had 

 been improperly classed with the lower series, inasmuch as they consi- 

 dered these rocks to be equivalent to the beds usually termed coal-measures. 

 The inferior rocks they divided into five subordinate groups." In the 

 same page Mr. De la Beche also states the substance of our subsequent 

 paper (1S37) read before the Geological Society (See Report, p. 43.). 



