Geological Society. 543 



GEOLOGICAL SOCIETY. 

 [Continued from p. 478.] 

 December 1, 1858. — Prof. J. Phillips, President, in the Chair. 



The following communication was read : — 

 " On the Geological Structure of the North of Scotland and the 

 Orkney and Shetland Islands." Part II. By Sir R. I. Murchison, 

 F.R.S., V.P.G.S. 



In a paper read during the last Session (see " Abstracts," No. 10) 

 the author described the general succession of rocks in the Northern 

 Highlands, as observed by Mr. Peach and himself, aided by the re- 

 searches of some other geologists. 



The rocks were described in their ascending order, as, first, a fun- 

 damental gneiss traversed by granite-veins at Cape Wrath ; secondly, 

 a red or chocolate-coloured sandstone and conglomerate, of great 

 thickness, and regarded by the author as of Cambrian age ; thirdly, 

 succeeding un conform ably, is a series of quartzite, with intercalated 

 limestone, both of them often highly crystalline, — from the lime- 

 stone Mr. C. Peach had succeeded' in obtaining, " near Durness," 

 several fossils, shown to be of Lower Silurian age ; fourthly, mi- 

 caceous schists and flagstones occupying a wide extent of country 

 to the east of Loch EriboU, described as being of younger age than 

 the foregoing, and older than the Old Red Sandstone series which 

 occupies the North-eastern Highlands and a great portion of the 

 eastern coast of Scotland ; fifthly, the Old Red series, arranged by 

 the author into three divisions, the middle being the Caithness Flags, 

 In the past autumn Sir Roderick, feeling that several points re- 

 quired stricter examination, revisited the country already described, 

 extending his researches both east and west, and to the most 

 northernly point of the Shetlands. 



In this tour he not only conhrmed his views previously announced 

 with regard to the succession of the older rocks, but examined 

 the structure of the Orkneys and Shetlands, more clearly defining 

 the relations and physical characters of the beds there composing 

 the Old Red Series. 



The present memoir comprised the details of these later observa- 

 tions ; and Sir Roderick acknowledged the aid he had cLiive.l from 

 Mr. Peach (who accompanied him throughout the journey), Mr. 

 John Miller, Rev. Mr. Gordon, and others ; and he referred to the 

 previous memoirs of Mr. Cunningham and Hugh Miller on Suther- 

 land, &c., and Dr. Hibbert on the Shetland Islands. 

 The principle points dwelt upon in this paper were — 



1. The evidence obtained at various points, that tlu Lower Si- 

 lurian limestone is intercalated in quartz-rock (east of Loch Eriboll, 

 Assynt, ike). 



2. That the Durness limestone lies in a basin supported by quartz 

 rock on the cast as well as on the west. 



3. That certain igneous rocks, connected with the DurncBS 

 trough, are protruded near Smo, which had not before been noticed. 



4. On this occasion corroborative evidence was adduced of the 



