Reviews — Geologij of Oban and Dahnallij. 179 



a later date than the movements which caused their foliation"; and 

 a fine view is given of " Coire Creachainn" (elsewhere apparently 

 spelt Cruachan). 



It is difficult, however, to find in any one place a good description 

 of the rocks and features depicted in the above-mentioned plates, nor 

 have we come across any discussion of the probable ages of the granites. 



Around Oban, as pointed out, the Lower Old Red Sandstone rests 

 on black schists of the Highland Series, and the basal portion consists 

 of coarse conglomerates which pass upwards into sandstones and shales. 

 The conglomerates are remarkable for the immense pebbles and boulders 

 of andesite which they contain, some of the blocks weighing nearly 

 half a ton. Hence the volcanic phenomena of Lome did not commence 

 with the lowest lavas of the plateau, which overlie the conglomerates 

 and some of the sandstones, but " lava-flows must evidently have been 

 erupted before any of the visible conglomerates began to be formed". 

 In the sandstones immediately above the conglomerates remains of 

 Cephalaspis, PterygoUts, and Kampecaris have been found. 



The evidence of the presence of Carboniferous rocks at the Bridge 

 of Awe, at the north-west end of the Pass of Brander, was established 

 during the course of the Geological Survey. The strata, previously 

 regarded as Old Bed Sandstone, consist of conglomerates overlain by 

 variegated marls, purple shales, and sandstones. Some fossils have 

 been found in the shales, and they include Asterocalamites scrobiculatus, 

 Schl., identified by Dr. Kidston, and a mollusc almost identical with 

 Modiola Macadami, Forth, determined by Dr. Peach. The fossils 

 favour the view that the beds are Lower Carboniferous. The 

 superficial deposits are not extensive. Mr. Kynaston remarks that 

 "the glens, as a rule, are narrow and the hills bold and steep, so that 

 surface accumulations would be apt to be rapidly carried away in 

 a climate characterised by a high rainfall". 



Abundant evidence of glaciation is met with in the polished and 

 sti'iated surfaces of the rocks, and in the mounds of morainic material 

 which fill the glens. The phenomena are attributed for the most part 

 to the period of later glaciation, and this applies also to the small 

 areas of boulder-clay in the Kilchrenan area and elsewhere. Fluvio- 

 glacial gravels, which occur in places, have been traced into the 

 100 foot beach. 



Baised beaches at elevations of 50 and 100 feet are noticed. The 

 cliffs bounding the 50-foot beach are here and there hollowed out 

 into caves, some of which " bear evidence from their contents of 

 having been inhabited from before historic times down to the present ". 

 A little more information might perhaps have been given respecting 

 them. We notice in the Bibliography that there are titles of papers 

 on'the caves, but there is no reference to these in the text. The same 

 remark unfortunately applies to many other papers in the Bibliography, 

 and we are at a loss to know to what extent others have contributed 

 to a knowledge of the geology of the district. 



Economic Geology occupies one chapter of two pages, relating to 

 granite and other building-stones, slate, lime, road-metal, and material 

 for pottery manufacture. Peat is dealt with in the previous chapter, 

 but there is no mention of water-supply. 



