59 



tricts 5 but very little has yet been published upon it. And on the 

 mountainous tracts in Wales, the ancient and very interesting essay 

 of Owen *, and the valuable papers of Mr. Aikin and Professor 

 Henslow, with that of Mr. De la Beche on Pembrokeshire, and of 

 Mr. Martin on the Coal Basin of Glamorganshire f, — a tract on which 

 Mr. Conybeare is occupied at present, ■ — comprehend nearly every 

 thing that deserves to be mentioned here. 



In Scotland also, notwithstanding the graphic and copious illus- 

 trations of Dr. MacCulloch, and the mineralogical skill and perse- 

 verance of other eminent naturalists who have applied themselves to 

 the Geology of their native country, — no geological map has yet ap- 

 peared 5 and a great part of that rich and varied region remains to be 

 explored. But the Society will have pleasure in observing, in the last 

 portion of their Transactions J, that an effective comparison of the 

 more recent strata of Scotland with our English formations has 

 been already begun. The memoir of Mr. Murchison on the Brora 

 Coal-field is an excellent specimen of what may be effected in this 

 department of inquiry ; and a paper produced at the last meeting by 

 the joint labours of Professor Sedgwick and Mr. Murchison, leaves no 

 doubt that the remaining memoirs which are to be expected from 

 those gentlemen, will throw great light on the comparative geology 

 of that distant portion of our island. 



The value, however, of the researches and identification at Brora, 

 goes much further than the mere comparison of a remote tract, with 

 the stratification of England : they confirm a suggestion of Dr. Buck- 

 land and Mr. Lyell, that the coal formation of that neighbourhood 

 was in reality the equivalent of a portion of our Oolitic strata ; and 

 demonstrate the remarkable fact, that the same fossils which in En- 

 gland occur in oolitic limestone, exist there in strata of quartzose sand- 

 stone and of shale ! The whole series indeed, of the phenomena 

 developed by recent examination in Scotland and the north of En- 

 gland, gives rise to the most interesting speculations on the questions 

 of geological identity, and of the relative value in geology of mine- 

 ralogical and zoological characters, — which has been so ably treated 

 by Brongniart and other continental writers : — questions, which it is 

 necessary to keep continually in view, and that acquire f resh interest 

 and importance in proportion as we extend our researches to the re- 

 moter districts of the world. 



To those amongst us who are confined to England, the most use- 



* Dated in 1570: — See Cambrian Register, for 1/96, and Geol. Trans. 

 N. S. Vol. I. page 312. 



f Philosophical Transactions, 1806. page 342. 

 I Second Series, vol. ii. p. 293. 



