1858.] MTJUCHISON NOETHERN HIGHLANDS, ETC. 395 



tiguous and subjacent rocks, — the derivative beds having always 

 a strike and dip different from those of their parent crystalline 

 rocks ; any approach to an agreement in their relations being local 

 and accidental. Allusion has already been made to the great change 

 observable in the outline and aspect of the country when we pass 

 from the one to the other group of rocks ; and it is useless to enume- 

 rate the numberless cases which have fallen under my own obser- 

 vation, where the younger deposit overlies in slightly inclined layers 

 the highly inclined crystaUine strata, which, together with an occa- 

 sional boss of granite or syenite, have invariably afforded the mate- 

 rials out of which the Old Eed strata have been composed. 



Describing some striking examples of the lower conglomerate, we 

 shall see how it passes up gradually into the Caithness Flagstones. 



On the east coast of Caithness, inclined both to the west and east, 

 the Old Red conglomerate and sandstone clasp round the quartz -rocks 

 of the Scarabin Hills. When adjacent to the quartz-rock, the Old 

 Eed conglomerate abounds in its fragments ; but on the east and 

 south of Braemore, granite and gneiss are added to the debris. I 

 ascertained, by passing along the summits of the rugged Scarabin 

 Hills, that the Old Red conglomerate is there almost entirely com- 

 pounded out of the white quartz-rock on which it rests *. 



This feature is remarkably well seen on the western slope of the 

 Scarabins, where the white brecciated conglomerate, in twisted sheets, 

 dips off the various shoulders of the quartz mountain, to the W.S.W. 

 and N.W. Other conglomerates, whether capping the detached and 

 lofty Morven, or its peaked and low satellites, the Maiden Pap and 

 the Schmian, being further removed from the pure quartz, are more 

 or less red, and were described by Professor Sedgwick and myself 

 thirty-one years ago, when we ascended the Schmian f. 



In descending the River of Langwell, the usual conglomerate is 

 seen to be equally local ; for there, whether it rests upon the newer 

 gneiss and grey-coloured flagstones, or on the associated and eruptive 

 granitic rocks which range from the Ord and across Ousedale, it is 

 found to be of a prevailing red colour, chiefly due to the prevailing 

 quantity of granitic fragments. In further descending the stream 

 from these bosses of conglomerate to the bridge under the House of 

 Langwell, a grand succession of thin-bedded deep-red sandstone is 

 exhibited, which, dipping to the E. and E.N.E., cannot have less than 

 a thickness of 800 or 1000 feet. 



Now, aU this thin-bedded sandstone (fig. 9, h, c), which passes 

 under and graduates upwards into the series of Caithness flagstones, 

 did not afford to the patient search of Mr. Peach the trace of a fish, 

 any more than it did to my former endeavours. It is this great lower 

 member of conglomerate and thin-bedded sandstone, which I have no 

 hesitation in considering to be the representative in time of the 



* I made this last examination fi'om the hospitable mansion of the Right 

 Honourable the Speaker and Lady Charlotte Denison, in September 1858. The 

 Scarabin is probably derived from the Graelic word Skearach (rough), and ben or 

 hein (hill). 



t See Trans. Geol. Soe. 2nd ser. vol. iii. p. 138, 



