400 Geological Society :— 



form the eastern wing of a huge anticlinal of granites ; on the 

 western base of this central chain younger granites of secondary age 

 support semimetamorphic strata. The eastern side of the arch con- 

 sists of a succession of huge folds of dioritic sandstones, clayslates, 

 and breccias, overlain by either Upper Devonian or Lower Carboni- 

 ferous strata. 



The Southern Alps are bounded on the eastern side by a belt of 

 old Tertiary quartzose trachytes and pearlstones, on which repose 

 extensive agglomeratic and tufaceous deposits (clays, sands, and 

 lignite bands) ; these are succeeded by thick-bedded calcareo-arena- 

 ceous strata, — the whole broken through by Dolerites, which in 

 their turn are covered by sand, clays, and thin limestones, probably 

 of Pliocene age. 



The author concluded by describing the Postpliocene moraine- 

 accumulations which are found on both sides of the Southern Alps. 



7. "On the Chemical Geology of the Malvern Hills." By the 

 Rev. J. H. Timins, M.A., F.G.S. 



From a detailed examination and analysis of the rocks composing 

 the Malvern Hills, with a view to the determination of the chemico- 

 physical processes which have contributed to their formation, Mr. 

 Timins has arrived at the following general conclusions in regard to 

 those rocks of eruptive origin : — (1) that, in the intrusive trap-rocks, 

 the ratio of the oxygen of the silica to that of all the bases taken 

 together, varies progressively from 5 : 4 to nearly 2:1; (2) that the 

 relative proportions of the several bases vary considerably in different 

 rocks, and often characterize particular localities ; (3) that the che- 

 mical composition of the eruptive rocks does not vary according to 

 their age ; (4) that the atomic proportion of the silica to the bases 

 is generally highest in the largest masses of trap, and lowest in the 

 smallest masses ; (5) that in the same masses of trap there is an 

 appreciable increase in the silica towards their centres, and that the 

 primary source of all the trap-rocks in the Malvern Hills was nearly 

 a bisilicate, which, during the various processes by which it has 

 been brought to the surface, has become united more or less with 

 other substances, assimilating metallic oxides, lime, magnesia, or 

 alkalies, according as one or another might be locally prevalent, just 

 as, in modern times, the lava of Vesuvius takes up soda, and that of 

 Etna lime ; and (6) that in all the eruptive rocks the atomic propor- 

 tion of the silica to the bases varies according to a common law. 



8. " On the Relative Distribution of Fossils throughout the North 

 Devon series." By Townshend M. Hall, Esq., F.G.S. 



The author gave a table showing the relative distribution of the 

 organic remains throughout the members of the Devonian system of 

 North Devon. The subdivisions of the rocks employed by Mr. Hall 

 are : — (1) The " Piiton Beds," highly fossiliferous ; (2) " Cuculleea 

 Zone," a term proposed in place of that of the " Marwood Beds," 

 and suggested by the abundance of the shells of several species of 

 Cucullcea, which are contained in the sandstone of the series ; (3) 

 the " Morthoe group," unfossiliferous; (4) the " Ilfracombe group," 



