40 



SCIENTIFIC NEWS. 



[July 13, 1888. 



The second set of striations was referred to the ice of 

 the Scottish Glacial System, and evidence was cited from 

 the researches of Messrs. Symes and McHenry, Dr. 

 Geikie, and others in support of this view, which is con- 

 firmed by the relative positions of the boulders 

 and their parent rocks. Striae bearing westward 

 have been observed at a height of 1,100 feet in co. 

 Mayo. 



The effects of the Irish Glacial System have been con- 

 sidered by the Rev. W. Close, Mr. G. H. Kinahan, and 

 Prof. Hull. Striations occur up to 1,340 feet in Donegal. 

 The ice of this system flowed in a general S.E. direction 

 to the S. of the axis. 



With regard to the relative age of the two set of striae, 

 it is observable that those bearing northward are by far 

 the most numerous ; so that although it is reasonable to 

 suppose that as a considerable accumulation of snow and 

 ice obtained in the Irish area whilst the Scotch system 

 was gathering its maximum strength, the striations pro- 

 duced by this gathering would be largely effaced by the 

 westward-flowing Scotch ice ; and that, after the decline 

 of the latter, an independent Irish mer de glace flowed 

 northward and southward, finding its axis of movement 

 in the great central snow-field. 



" Evidence of Ice-Action in Carboniferous Times." By 

 John Spencer, Esq., F.G.S. 



The author combated the notion that there is any a 

 priori improbability in the action of ice during the period 

 in question. In the case under consideration, of the two 

 agents, land-ice or floating-ice, he was inclined to adopt 

 the latter, as having been the cause of the phenomena he 

 described. The bed affected is the Haslingden Flag-rock, 

 a member of the Millstone-Grit series, which is directly 

 covered by a shale of the same series. The surface of 

 this Flag-rock is largely striated, the striae having a N.E. 

 and S.W. direction, and being nearly parallel. The 

 area exposed is 200 square feet. The Flag-rock dips to 

 the east at an angle of 30 ; but there seems no possibility 

 of these striae having been produced by landslips or local 

 disturbance. A quarry on the same horizon, near Roch- 

 dale, exhibits similar phenomena. As collateral evidence 

 of ice-action, he alluded to the boulders frequently found 

 in the coal-seams. 



In the subsequent discussion, Mr. Topley said the 

 question of the striae was difficult to decide ; but he 

 thought the reference to boulders in a coal-seam a 

 thousand feet above did not help matters. He considered 

 the appearances due most probably to movement of the 

 nature of slickensides. It was too hazardous to put it 

 down to ice-action. 



" The Greensand bed at the base of the Thanet Sand." 

 By Miss Margaret I. Gardiner, Bathurst Student, Newn- 

 ham College, Cambridge. Communicated by J. J. H. 

 Teal, Esq., M.A., F.G.S. 



This bed may be seen between Pegwell Bay on the 

 east, and Chiselhurst on the west, and a somewhat 

 similar bed occurs at Sudbury, Suffolk. An examina- 

 tion of the Kentish layer showed it to consist of 45 per 

 cent, of quartz, 15 per cent, of glauconite, and 40 per 

 cent, of flint. Amongst the rarer minerals are felspar, 

 magnetite, spinel, zircon, garnet, rutile, tourmaline, 

 actinolite, epidote, and chalcedony ; and there are a few 

 microscopic organisms, either Radiolarians or Diatoms, 

 and some Foraminiferal casts. 



The Sudbury greensand has 75 per cent, of its grains 

 consisting of glauconite, and of the quartz and flint- 



grains only 10 per cent, are flint; several of the rarer 

 minerals found in Kent occur here also. 



The large flint-percentage in the Kentish grains was 

 alluded to in support of the existence of an unconformity 

 at the base of the Tertiary deposits of that area ; and the 

 relatively small percentage of flint in the sands now 

 being formed along a very similarly situated shore, was 

 suggested to be due to the drifting of debris derived from 

 the coasts composed of Tertiary and Wealden rocks, 

 which became mixed with the material brought down by 

 the Thames. 



" On the occurrence of Elephas mcridionalis at 

 Dewlish, Dorset. By the Rev. O. Fisher, M.A., 

 F.G.S. 



The author's attention was first drawn to this subject 

 on seeing two molars of an elephant in the Blackmore 

 Museum labelled " Dewlish, Dorset." He at once 

 attributed them to E. meridionalis. Subsequently he 

 ascertained that they were part of a find made in 1813 

 by a Mr. Hall. Dr. Falconer, from rubbings, attributed 

 the teeth to E. antiquus ; and Dr. Leith-Adams would 

 not allow that they belonged to E. mcridionalis, because 

 that species had never been found so far west. Last 

 year the author and Mr. Mansel-Pleydell went to Dew- 

 lish, and the latter has since continued the workings. 

 The remains have been found high up on the face of a 

 steep chalk scarp facing west, ten feet below the brow 

 and ninety feet above the existing stream, in such a 

 position as to suggest that the deposit was the result of 

 an undercut of the stream when it flowed at a higher 

 level. 



" On Perlitic Felsites, probably of Archaean age, 

 from the flanks of the Herefordshire Beacon, and on the 

 possible Origin of some Epidosites." By Frank Rutley, 

 Esq., F.G.S. 



The author has previously described a rock from this 

 locality in which faint indications of a perlitic structure 

 were discernible. In the present paper additional in- 

 stances were enumerated and a description was given. 

 The perlitic structure is difficult to recognise, owing to 

 subsequent alteration of the rock. 



The author suggested, from his observations, that 

 felsites, resulting from the devitrification of obsidian, 

 quartz-felsites, aplites, etc., may, by the decomposition 

 of the felspathic constituents, pass in the first instance 

 into rocks composed essentially of quartz and kaolin ; 

 and that by subsequent alteration of the kaolin by the 

 action of water charged with bicarbonate of lime, and 

 more or less carbonate of iron in solution, these may 

 eventually be converted into epidosites. 



He regarded it probable that the rocks are of later 

 Archean or Cambrian age. 



"The Ejected Blocks of Monte Somma. Part I. 

 Stratified Limestones." By H. J. Johnston-Lavis, M.D. 

 F.G.S. 



Introductory. — The author referred to the Hamilton 

 collection, now in the British Museum, and to the work 

 of Professor Scacchi, who enumerates 52 mineral 

 species as having been found in the ejected blocks, and 

 indicated the importance of these from a geological and 

 volcanological point of view. His own collection con- 

 tains over 600 specimens, showing the graduation from 

 unaltered limestones, through various stages of change 

 into numerous varieties of " true metamorphic rocks," 

 which, in their turn, shade into igneous rocks more and 

 more approaching the several modifications of the normal 



