110 Mr. Weaver on the Older Stratified 



tified Mocks of Devonshire and Corwisoall*, my Memoir on 

 North Devon f is adverted to, and some allusion is also made 

 to Ireland. I have much regretted that the state of my health 

 has for a considerable time past prevented my attending the 

 meetings of the Geological Society, or any one of those of the 

 British Association. It would otherwise have afforded me 

 greater satisfaction to have given any explanation that might 

 have been required viva voce, rather than to have recourse 

 to writing that which may now be deemed necessary. 



With respect to the relative age of the culmiferous rocks 

 of Devon, extending from the siliceous or argillaceous shales 

 and carbonaceous limestone upward, it appears now to be 

 generally admitted that they belong to the carboniferous 

 series. But it is contended that from those siliceous and ar- 

 gillaceous shales downward there is both a conformity with, 

 and a gradation into the subjacent Trilobite clayslates, which 

 constitute the northern boundary of the carboniferous trough ; 

 and that this body of clayslate (according to the Rev. D. 

 Williams three to five miles wide) with subordinate layers of 

 limestone, together with the other old stratified rocks, (com- 

 posed, in a descending order, of the Wollacomb and Mar- 

 wood sandstones, Morte clayslates, Ilfracombe, Berry-narbor 

 and Comb Martin limestones, Trentishoe sandstones and clay- 

 slates with quartzy clayslates and quartz-rock, Linton clay- 

 slates with beds of quartz-rock and sandstone and layers of 

 limestone, and the Foreland sandstone), are to be considered 

 as the equivale7its of the Old Red Sandstone, and not referable 

 partly to the Silurian and partly to the Cambrian system, as 

 formerly stated J. As I do not concur in these new views, it 



is a word of common use, applicable in many senses. On the other hand, 

 the term protozoic, as signifying a class of rocks which entombs the remains 

 of the earliest of created beings, being of a more confined and definite cha- 

 racter, may be well entitled to our acceptation. 



* Lond. and Edinb. Phil, Mag. April 1839, and Proceedings of the 

 Geological Society, 24th April 1839. 



t Proceedings of the Geol. Society, Jan. 1838, and L. &E. Phil. Mag. 

 July 1838, Supplement. 



X In the views previously entertained by the authors, the older strati- 

 fied rocks of North Devon were distributed into five mineral masses, of 

 which the four lower were referred to the upper part of the Cambrian 

 system, and the fifth, or uppermost, to the lower part of the Silurian ; while 

 of the highest group of all, in the order of succession, the culmiferous series, 

 it was shown that they cannot forma true passage into the different schistose 

 rocks upon which they rest. (Proceedings of the Geological Society, June 

 1837, and in particular pp. 560 to 5G2.) See also the masterly views 

 developed by Prof. Sedgwick {Ihid. May 1838, pp. 675, 676, etseq.). 



The authors now refer the Older Stratified Rocks of Devon to a position 

 intermediate between the Silurian and Carboniferous systems. (Lond. and 

 Edinb. Phil. Mag., vol. xiv, pp. 248, 259. April 1839.) 



