Reports and Proceedings — Geological Society of Glasgow. 277 



diabases, and picrite-porphyrites are placed only in the latter. 

 Explanatory notes on the minei-alogical tables succeed, and these 

 contain a good many useful hints on the determination of some 

 microscopical characters and the application of optical tests. 



Finally come the determinative tables, arranged under such heads 

 as the Felspars, Micas, Silicates and Oxides, Zeolites, Iron-ores, 

 Alteration products, and the like, reference being made easy by 

 a separate index of minerals. 



The work is likely to be very useful to the beginner from the 

 simplicity of its arrangement and the avoiding of all controversial 

 matter, while even to the advanced student it will furnish a most 

 valuable aid to memory, which will save the trouble of reference to 

 larger works at the same time that it will make such reference 

 more easy. 



:K,E]I=0K,TS ^^n^HD IF'S-OG-EEHDIira-S- 



Geological Society of Glasgow : May 9, 1895. 



The " Shelhj Clays'' and the Great Ice Age.— Mr. Ddgald Bell, 

 F.G.S., read a paper "On the High-level Shelly Deposits, and 

 their bearing on the question of Submergence ; with special 

 reference to the recent edition of Dr. James Geikie's Great Ice 

 Age.'' Dr. Geikie had intimated that he no longer believed in a 

 "great submergence" of about 1400 feet during the Glacial period, 

 which had been inferred from such high-level shelly "drifts" as 

 those of Moel Tryfaen, in Wales. These, he admitted, were most 

 probably transported to their present position by an ice-sheet. He 

 still, however, believed in a submergence of from 500 to 600 feet, 

 the evidence for which rests on one or two instances of high-level 

 shelly clay in the west and north of Scotland. Indeed, it may be 

 said to rest on only one instance ; for the Aberdeenshire " beds," it 

 was tolerably clear, could not be accepted as proofs of submergence ; 

 and another and, till lately, leading instance was in this edition 

 " conspicuous by its absence." Chapelhall, near Airdrie, which had 

 figured so largely in connection with this subject for forty years, 

 and on which great stress was formerly laid by Dr. Geikie, is now 

 entirely omitted, without a word of explanation ! It seemed unusual 

 to allow one's favourite facts thus to sink out of sight, without some 

 brief In Memoriam being inserted where they once figured so 

 largely. But Chapelhall being thus summarily discarded, Clava, 

 near Inverness, which had become known since the last edition, 

 might be said to be the single instance on which Dr. Geikie had to 

 rest his proof of a submergence of about 500 feet. It was, so to 

 speak, the " a'e button," which had to bear a great " responsibility." 

 Accordingly, in this edition, much is made of Clava. A minority of 

 the investigating committee were inclined to think that the shelly 

 deposit there may have been transported by ice to an elevation of 

 500 feet, just as that of Moel Tryfaen had been to an elevation 

 of 1400 feet. But Dr. Geikie will have none of this. Moel Tryfaen 

 he admits, but Clava, he thinks, would be a "freak" of the ice, and 



