156 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 13, 



although he allows that this is most likely much too great an esti- 

 mate. We may safely say, however, that the total thickness is 

 some thousands of feet. 



The spot that yielded the jaw of Hyperodapedon, the first and, as 

 yet, the only fossil of the "I^ew Red" of Devonshire, is on the left bank 

 of the Otter, just above its mouth, where the sandstone is somewhat 

 brecciiform. The specimen was in a large block which had fallen 

 from the low cliff that bounds the estuary, and was found by my 

 friend Mr. J. E,eid, of Canterbury, and myself. 



The stratigraphical position of the fossil is therefore the lower 

 part of the uppermost bed of sandstone (No. 3 of section), and con- 

 sequently it belongs to the upper part of the formation. 



That the upper part of the '• New Ked " of this county belongs to 

 the Trias is clear from its passage upwards into the Lias ; and as the 

 different divisions seem to succeed each other conformably, we are 

 led to infer that they all belong to the same formation, although the 

 lowest division is more like the Permian of some districts. Mr. Pen- 

 geily has gone into the question of the age of the breccia of Teign- 

 mouth &c. in detail * ; and it will be well to give the leading points 

 of his argument, which are as follows, to state them in as few words 

 as possible : — 



The Dartmoor granites are thought to be of three different ages,, the 

 newer cutting through the older. All of these send veins into the 

 Carboniferous rocks, and are therefore newer than that formation. 

 Fragments of all three granites have been found in the " New-Red '' 

 breccia. Therefore, between the time when the Carboniferous rocks 

 were consolidated and the time when the " New Red " began to be 

 deposited, the following events must have taken place: — 1. All the 

 three sorts of granite must have been successively formed. 2. The 

 thick crust above them must have been denuded to allow of pebbles 

 being worn out of them. These things must have taken vast time 

 ■ — time so great as to make it very unlikely, if not impossible, that 

 even the lowest part of the red rocks can be Permian. 



The above reasoning seems conclusive, as far as it goes, and indeed 

 can only be shaken by attacking the data on which it is founded. 

 One of these data is a tacit assumption that there was no very great 

 time, geologically speaking, between the close of the Carboniferous 

 and the beginning of the Permian period. My colleague, Mr. Hull f, 

 has since shown, however, that in Lancashire and Yorkshire there 

 is a great unconformity between the rocks of those ages, and that 

 the Carboniferous rocks have in parts been denuded to the extent of 

 very nearly 10,000 feet in vertical thickness, and perhaps at one 

 part to the extent of more than 19,000 feet, before the deposition of 

 the Permian beds. When it is remembered that this great denuda- 



^ Trans. Plymouth Inst, for 1861-62, pp. 27-30, and Presidential Address 

 to the Devon. Assoc, of Lit. Sci. & Art, 1867. 



t Quart. Journ. Geol. Soc. vol. xxiv. pp. 327-329. 



