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XX. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued from vol. xvii. p. 559.] 



February 20, 1884.— Prof. T. G. Bonney, D.Sc., F.R.S., 



President, in the Chair. 



THE following communications were read : — 

 1. "Ona recent Exposure of the Shelly Patches in the Boulder- 

 clay at Bridlington." By G. W. Lamplugh, Esq. 



2. " On the so-called Sjoongia paradoxica, S. Woodward, from 

 the Red and White Chalk of Hunstanton." By Prof. T. McKenny 

 Hughes, M.A., F.G.S. 



3. " Further Notes on Bock-fragments from the South of Scotland 

 imbedded in the Low-level Boulder-clay of Lancashire." By T. 

 Mellard Reade, Esq., C.E., F.G.S. 



In his paper on the Drift-beds of the North-west of England, 

 Part II., Q. J. G. S. 1883, p. 119, the author noticed that the dis- 

 covery of Criffel-granite erratics in the Lancashire drift first made by 

 Mr. Mackintosh, had been confirmed by Mr. P. Dudgeon, from speci- 

 mens forwarded by the author in 1882. In August of last year, he 

 had an opportunity of travelling from Dumfries through Kirkcud- 

 bright to Wigtonshire, and of examining the rocks and the boulders 

 derived from them. Two masses of granite have broken through 

 Silurian strata in Kirkcudbright : the eastern of these granite masses 

 forms the isolated mountain of Criffel, 1800 feet above the sea ; the 

 western rises to 2331 feet, and is known as Cairnsmore of Fleet. 

 The granite of the former is, as a rule, finer than that of the latter. 

 Numerous boulders derived from both are found in the surrounding 

 country. 



The author pointed out in detail how different varieties of granite 

 observed on Criffel and Cairnsmore of Fleet are clearly the rocks of 

 which fragments are found in the drift of Lancashire ; and also 

 showed that the Silurian " Grey wacke's " through which the granite 

 of the mountains named has burst, are also represented by unmis- 

 takable specimens in the Lancashire Boulder-clay. The " Grey- 

 wacke " varies in texture from a fine-grained sandstone to a coarse 

 gritty sandstone, and in colour from dark blue and grey to deep 

 purple-red. These beds, which belong to the Queensbury-grit 

 gravels, are well seen in a line of cliffs called the Craigs of Garheugh, 

 at the side of the road from Glenluce to Fort William. Specimens 

 identical with these rocks have been found in the low-level Boulder- 

 clay of various parts of Lancashire, as at Great Crosby, Innewick 

 Fishery, and the Isle o£ Whithorn. 



These identifications go far towards completing the identification 

 of the rocks represented in the low-level Boulder-clay of Lanca- 

 shire, and confirm the views already expressed by the author that 



