the Primary Rocks and the Oolitic Series in the North of Scotland. 153 



forty feet in length, for the purpose of constructing^ columns. They are all 

 hewn out into large troughs and cisterns, and the hardest of the blocks have 

 been occasionally used for millstones, — a purpose for which, however, they do 

 not seem to be well adapted. The higher parts of the hill seem to be com- 

 posed of stone of nearly the same quality, but no quarries have yet been 

 opened in them. 



We do not attempt to enter upon any further details respecting the secon- 

 dary deposits on the southern shores of the Murray Firth, but, from what has 

 been stated, it appears that they may be divided into three groups, the lowest 

 of which is composed of red sandstone and conglomerate — the middle, of sand- 

 stone associated with variegated marls and cornstone — and the highest, of 

 light-coloured siliceous sandstone. These three groups are, however, very 

 ill-defined; and, as in our examination of this part of the country we did not 

 visit all the successive promontories to the east of Burg-head, there may be 

 other beds superior to the white sandstone which are not noticed in this trans- 

 verse section. 



A peculiar character is given to the deposits here described by the great 

 abundance of cornstone, which may perhaps be considered to replace the 

 lower portions of the calcareo-bituminous schist. Whatever be its relations, 

 its appearance is not to be regarded as altogether anomalous ; for, in the 

 county of Sutherland (especially in the immediate neighbourhood of Golspie, 

 and between that place and Loch Fleet), there are several examples of this 

 peculiar, concretionary limestone associated with the red sandstone which 

 alternates with, and overlies the old conglomerates. And there may be many 

 other examples of cornstone with similar relations, which, in the transverse 

 sections through the secondary series, entirely escaped our notice. 



Red Sandstone and Conglomerate Series of the North-west Coast of Sutherland 



and RosS'Shire. 



These deposits stretch almost without interruption from the neighbourhood 

 of Cape Wrath to the southern extremity of Applecross, and are developed 

 on an enormous scale, sometimes rising into pyramidal mountains more than 

 3500 feet in height. For their general description and mineralogical cha- 

 racters, we must refer to the works of Dr. MacCulloch ; but it may be proper, 

 very briefly, to notice the phaenomena exposed by the excavations for the new 

 road over the red sandstone mountains of Applecross, as this great work fiad 

 not commenced at the time he visited the western Highlands. Tiie road 

 ascends by traverses, frequently conducted in the solid rock, to a great eleva- 

 tion, and affords an admirable opportunity for studying in detail the structure 



VOL. III. SECOND SERIES. X 



