the Neighbourhood of Gamrie, Banffshire. 141 



ancient rocks, as forming the base on which the younger deposits were accu- 

 mulated, and as exhibiting a type of the general character of the slate series of 

 the district. 



Upon a bed of light-coloured, fine-grained gneiss, exhibited occasionally in some of the anti- 

 clinal lines, reposes a beautiful variety of mica slate, consisting of slightly waved beds, alternately 

 of a silver grey and light red colours, and occasionally studded with imperfectly crystallized gar- 

 nets. These strata pass up into siliceous beds, consisting of a colourless quartz with a small quan- 

 tity of hornblende ; and are succeeded by argillaceous schists alternating with coarse roofing slate; 

 which in turn are overlaid by strata of dark micaceous schist with waved surfaces, the uppermost 

 beds being light grey and dark red, sandy and argillaceous. 



The minerals found in this formation consist, as usual, of crystalline white quartz in the veins 

 of the rocks; of a few small crystals of hornblende disseminated in some of the schists; and of 

 small, imperfect garnets in the mica slate. Chromate of iron is also found, in the state of fine 

 powder, in the sands at the base of the cliffs at Macduff, but the vein whence it was derived has 

 not been discovered. An excellent section of the slates is exhibited along the coast from Black- 

 pots to Gamrie ; the lowest and the middle parts being displayed between Blackpots and Banff*, 

 and the middle and upper parts between Banff and Gamrie. The strata are greatly contorted, and 

 present, especially near Macduff and between Blackpots and Banff, numerous anticlinal and syn- 

 clinal dips. 



Old Red Sandstone. 

 In the cliffs behind Gamrie, and in the brook at Crovie, the upper beds of 

 the schistose rocks pass apparently into the old red sandstone; strata of a dark 

 purplish sandstone at first alternating with slates, sandstones and marls, and 

 finally graduating into a bright red sandstone. 



This deposit is of great thickness, and is well characterized by its lithological structure. Its 

 lower beds form beautiful cliffs to the west of Gamrie, but the upper can be studied only on the 

 banks of the streams below Findon ; where, the friable sandstones and fine conglomerates of the 

 higher part of this formation crop out. These upper strata dip slightly south-west, and are ex- 

 posed in a succession of soft, red and yellow, slightly micaceous sandstones and marls, alternating 

 with thin, subordinate beds, containing a few pebbles of quartz and slates. In the descending 

 series, the beds become thicker, more compact, and of a brighter red streaked with yellow, and 

 the subordinate conglomerates gradually disappear. That part of the formation which crops out 

 on the coast, is peculiar (as I have before mentioned) for its fine bright red colour. In the lowest 

 beds, the yellow streaks are replaced by round, light yellow spots, about the size of a shilling, and 

 as regularly shaped. These beds are tolerably hard, and are used as a building-stone. I could 

 discover no fossils in any part of this red sandstone. 



Red Conglomerate and Clays with Ichthyolites. 

 A good, and indeed almost the only section of the Ichthyolite-bed, is exhi- 

 bited in a cliff, overhanging a small rivulet about 200 yards north of Mr. 



* Pl.X. Sec. No. 1. 



