122 PEOCEEDLNGS OF THE GEOLOGICAL SOCIETY. [Jan. 8, 



to the southward, and between it and Loch Brora, and at a number 

 of small exposures along the mountain-side. They are also seen on 

 the sides of Loch Brora, wherever the streams have cut sufficiently 

 deep to pass through the thick masses of moraine-matter which 

 mask the flanks of the mountains on either side of Strathbrora. 



South of the Loch we find in the Allt-Duchary * an admirable 

 exposure of the metamorphic (Silurian) strata, which here consist 

 in parts of a rock like that of the Clyne-Kirk gorge, but in other 

 parts of red and gray fine-grained gneiss, penetrated by veins of 

 red granite, and identical in character with the great mass of the 

 Silurian strata of the district. 



The next point at which a section is cut through the great mantle 

 of glacial detritus which covers the country is in the Sputie Brook. 

 Here the Jurassic sandstones, which are tolerably well exposed at 

 several points about Lppat, are seen in the bed of the brook ; and 

 at a short distance above, the Old Bed Sandstone and Conglomerate 

 are found in situ, having been brought to a much lower level than 

 near Loch Brora by the southerly dip of the strata, which seems to 

 be here greatly increasing in amount ; so that the Old Bed nearly or 

 quite overlaps the Silurian at this spot. 



At several points above Lppat and Dunrobin the Jurassic sand- 

 stones and clays are found dipping at considerable angles, but no 

 actual junction of the Primary and Secondary rocks is exposed. It 

 is evident, however, that the Jurassic strata lie against the Old Bed 

 Sandstones and Conglomerates, and that near the line of contact 

 they are greatly disturbed ; in one place they are seen dipping 

 N.E. 15°, while at a distance of about a quarter of a mile they dip 

 S.W. 30°. These sections are observed in sandstone pits opened in 

 the great deer-forest above Dunrobin Castle ; but here the surface 

 of the country is so greatly concealed as to render hopeless the task 

 of tracing out in detail the curves and dislocations of the strata. 



In JJunrobin Glen the Old Bed Sandstone strata show consider- 

 able signs of disturbance. Triassic strata appear, as will be here- 

 after described, lower down the glen ; but no actual contact with the 

 Old Bed is seen. At Bhives, near Golspie Inn, and in the cliff and 

 on the shore between Dunrobin and Golspie the same Secondary 

 rocks occur ; and these are the last localities at which they have been 

 detected in the county of Sutherland. Southward the beds of the 

 Lower Old Bed Sandstone are by their dip brought down to the 

 sea-level ; and at the extreme southern extremity of the county of 

 Sutherland, higher and fossiliferous strata of the same system make 

 their appearance f. 



The shores of the Moray Birth, with those of the several inlets 

 which open into it, namely Loch Fleet, Dornoch Birth, Cromarty 

 Birth, and Inverness and Beauley Births, are almost wholly composed 

 of the various strata of the Old Bed Sandstone, which succeed one 

 another in a regular manner, and with usually slight dips. But 



* Trans. Geol. Soc. 2nd ser. vol. ii. pt. 3. p. 355. 



t Murchison, Quart. Joum. Geol. Soc. vol. xv. (1859) p. 398. Joass. ibid. 

 vol. xsv. (1869) p. 318. 



