TKANSACTIONS OF SECTION C. 7 IS 



From Tyndrum, ^-c. A somewhat varying series of schists, but with a 

 common facies. Some have but little mica, consisting mainly of quartz and 

 felspar, and pale grey or reddish in colour ; others ai'e very micaceous schists of a 

 lead coloui', with sheen surfaces and indications of mineral banding. There are 

 also very quartzose gneisses of a white or pinkish white colour. 



Crianlarich and Killin, ^-c. Calc mica-schists, with sheen surfaces due to sub- 

 sequent pressure, but showing mineral banding ; also fine-grained gneisses like 

 some of those near Tyndrum. But as they have a very marked cleavage foliation 

 they may originally have been somewhat coarser grained. A garnetiferous mica- 

 schist from several places. 



Blair Athol, ^-c. Dark mica schists, with rather a carbonaceous aspect and a 

 very marked cleavage foliation. Some show on close examination along the edges 

 a speckled aspect, recalling some of the gneisses mentioned above. There is also 

 a fairly coarsely crystalline limestone, with specks and streaks of green serpentinous 

 material and some scattered pyrite ; also a calc mica-schist modified by pressure 

 and some quartzose schists. 



To the south of this line, as mentioned by the author in another paper (' Pro- 

 ceedings of the Geologists' Association,' vol. vii. p. 8-4), 'schistose and slaty chlor- 

 itic rocks become more abundant in association with micaceous rocks,' and 

 ' everywhere strongly recall to mind the pre-Cambrian rocks of Wales, especially 

 those in Anglesea and in the Lleyn Promontory.' 



4. On the Still-possible Caiiibrian Age of the Torridon Sandstone. 

 By J. F. Blake, M.A., F.G.S. 



The Torridon Sandstone had been last year removed from the Cambrian on 

 account of the discovery of a species of Olenellus in the unconformably overlying- 

 series. There is, however, an a priori improbability in the rock being pre- 

 Cambrian — amongst which in this country no red grits and conglomerates are 

 known — while this is everywhere the character of the Lower Cambrian, except in 

 particular isolated spots whose peculiarities are due to special conditions, and not 

 to the epoch of the deposits. The main points, however, are that the fauna of the 

 Durness Limestone had been examined by C. D. Walcott, of the United States 

 Geological Survey, and recognised by him as Ordovician, and not Cambrian, by 

 comparison with the American series, and that the species of Olenellus discovered 

 in these fucoid beds in Durness was not of the same section of the genus as those 

 which had been definitely found in position below the Olenus and Paradoxides 

 beds, and might even be separated as a distinct genus. The supposed pre- 

 Cambrian age of the Torridon Sandstone depended therefore only on the supposed 

 limited range of a genus of several sections, which limited range had never been 

 proved. 



5. On the Alleged Proofs of Submergence in Scotland during the Glacial 

 Epoch. By DuGALD Bell, F.G.S. 



I. Chapelhall, near Airdrie. 



The maximum degree of submergence in Britain during Glacial times has been 

 the subject of much discu.ssion among geologists. The view held till recently — 

 that it may have been 1,500 feet or more— is now generally abandoned. Minor 

 yet considerable degrees of submergence are still usually admitted — up to 500 or 

 GOO feet — one of the supposed proofs of which is the shelly clay that was found at 

 Chapelhall. 



riegarding this deposit little is really known. It was first recorded by Mr. 

 Smith, of Jordanhill, in 1850, from information supplied to him by Mr. Russell, 

 an operative miner, who came upon it at 510 feet above the sea in digging a 

 well. Some sheila, curiously enough all of one species, Tellina calcarea (proximo), 

 had been taken from it, and the clay has not been seen since. Sir A. Geikie, Dr. 



