32 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 19, 



Order of succession. — This review of the red sandstone and 

 quartzite as they appear in the long course of more than 1 00 miles 

 along; the west coast from Durness and Cape Wrath to Loch iVlsh 

 and Skye establishes the following important facts in the geology of 

 this part of Scotland. 



First. The red sandstone is the lower formation, resting only 

 upon gneiss, and forming a narrow band along the western shore, 

 never reaching to the watershed of the country, and not exceeding 

 twenty miles in breadth in its widest portions, as on the Gairloch. 



Secondly. The quartzite is a distinct and newer formation, resting 

 unconformably on the red sandstone on the west, but on the east 

 spreading out beyond it over the gneiss. Its present breadth, in- 

 cluding outlying portions, does not exceed ten miles, and is gene- 

 rally much less. The limestone forms the upper portion of this 

 band. 



Thirdly. That the general dip, though at a different angle, both 

 of the red sandstone and quartzite is to the south-east ; and that 

 at many points on its eastern side the quartzite and limestone 

 have been ascertained to dip under gneiss inclined in the same 

 direction. 



Organic remains. — This inferiority of a vast series of sedimentary 

 deposits — for what is true of the quartzite must be true also of the 

 red sandstone on which it rests — to a highly metamorphic rock like 

 gneiss has acquired additional interest from the discovery of undoubted 

 organic remains in some of the beds. These remains I shall now 

 notice in the order of the formations. In the red sandstone no organic 

 remains have been found, partly perhaps from the nature of the beds, 

 partly, we may presume, from the few opportunities they present, 

 from quarrying or other operations, for their discovery. In the 

 quartzite probable indications of organic beings are more numerous. 

 In his first Memoir on Quartz-rock, published in 1814, Dr. Mac- 

 cuUoch noticed the *' imbedded cylindrical bodies" seen both on 

 the surface and in the interior of the quartzite, and described them 

 as " the remains of some animal, a Sabella or other marine worm." 

 The organic origin of these bodies has subsequently been denied, 

 but as it appears to me erroneously. Consisting entirely of sand — 

 and thus rather casts than petrifactions — they can scarcely be ex- 

 pected to show any structure, so as to decide positively their true 

 character. Their branched forms and their immense numbers, 

 closely crowded together over wide spaces, are opposed to the view 

 that they are the mere burrows of marine worms, as Macculloch 

 suggested. Both in general aspect and mode of grouping the cylin- 

 drical forms much resemble the Lithodendron corals, whilst the 

 conical, rounded or polygonal bodies in other beds have more simi- 

 larity to Cyathophyllce. I shall, however, leave to further investi- 

 gation to determine their true nature, as at present we can draw no 

 argument from them in regard to the age of the strata. 



In other beds of the quartzite, I have mentioned plant-like im- 

 pressions as occurring in abundance. But these are in general nothing 



