1858.] 



MTJECHISOX NORTHEEN HIGHLANDS, ETC. 



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VOL. XV. PART I. 



dently referable to marine plants or 

 fucoids * ; but nowhere has anyone — 

 not even the keen-eyed Peach — col- 

 lected a form which can be referred to 

 terrestrial vegetation. The exact po- 

 sition of the SerpuUtes MaccuUochii 

 and the Fucoids, as thus given, is to be 

 traced over a considerable area, both in 

 the environs of Assynt and ia those of 

 Loch Eribol. 



It is to be observed that the siliceous 

 courses in which anneKdes occur, are 

 not to be considered a porous granular 

 quartz, as stated by Macculloch, but 

 as a hard compact rock which simply 

 becomes porous upon weathering, when 

 the fossils are best exposed. 



Instructive sections in ascending 

 order may be made, either from the 

 Kyles of Strome or from Loch Inver, 

 in Sutherland. The former, however, 

 is by far the most satisfactory, because, * 

 by slight deviations only from the road, 

 the passing traveller may satisfy him- 

 self of the truth of all the data of su- 

 perposition. Quitting the rugged bosses 

 of gneiss at the Perry, and ascending 

 to the summit-level of the road, he 

 soon meets with layers of the chocolate - 

 coloured Cambrian sandstone, which, 

 sweeping down to the road from the 

 lofty precipices of Queenaig, dip to the 

 W.N'.W. at the sKght angle of 5° or 6°; 

 so nearly do the beds of that very an^- 

 cient rock approach to horizontality. 



Here there is no ambiguity ; for the 

 chocolate- coloured Cambrian rock is 

 clearly superposed by sheets of the 

 compact quartz -rock, which dip from 

 20° to 25° to the S.E. In short, no 

 unconformity can be more striking; 

 and the quartz-rock, at the summit- 

 level of the road, rests on the shoulders 



* The fucoid-bed and its associates were 

 traced by Mr. Peach from Ledbeg near Loch 

 Awe, by Stronchrubie, Inchnadampf, Assynt, 

 Bridge of Skiag, and thence towards Kyle 

 Scow, and at two of these places Prof. Nicol 

 and myself had previously detected it. Mr. 

 Peach observed them in precisely the same 

 position on the eastern shores of Loch Eribol. 



2e 



