182 Reports and Proceedings — 



:r:e:po:r,ts .A_3src> zpiR-ociEiEiDxisra-s. 



Geological Society of London. — I. — January 27, 1875. — John 

 Evans, Esq., F.E.S., President, in the Chair. — The following com- 

 munications were read : — 



1. "On the Structure and Age of Arthur's Seat, Edinburgh." By 

 John W.Judd, Esq., E.G.S. 



The author said that Arthur's Seat, so long the battle-ground of rival 

 theorists, furnished in the hands of Charles Maclaren a beautiful illus- 

 tration of the identity between the agencies at work during past 

 geological periods and those in operation at the present day. 



One portion, however, of Maclaren's masterly exposition of the 

 structure of Arthur's Seat, that which requires a second period of 

 eruption upon the same site, but subsequent to the deposition, the 

 upheaval and the denudation of the whole of the Carboniferous rocks, 

 is beset with the gravest difficulties. The Tertiary and Secondary 

 epochs have in turn been proposed and abandoned as the period of this 

 supposed second period of eruption ; and it has more recently been 

 placed, on very questionable grounds, in the Permian. 



The antecedent improbabilities of this hypothesis of a second period 

 of eruption are so great, that it was abandoned by its author himself 

 before his death. A careful study of the whole question by the aid of 

 the light thrown upon it in comparing the structure of Arthur's Seat 

 with that of many other volcanos, new and old, shows the hypothesis 

 to be alike untenable and unnecessary. 



The supposed proofs of a second period of eruption, drawn from the 

 position of the central lava column, the nature and relations of the 

 fragmentary materials in the upper and lower parts of the hill respec- 

 tively, and the position of certain rocks in the Lion's Haunch, all break 

 down on re-examination. While, on the other hand, an examination 

 of Arthur's Seat, in connexion with the contemporaneous volcanic rocks 

 of Forfar, Fife, and the Lothians, shows that in the former we have 

 the relics of a volcano which was at first submarine, but gradually rose 

 above the Carboniferous sea, and was the product of a single and almost 

 continuous series of eruptions. 



2. " The Glaciation of the Southern Part of the Lake-District, and 

 the Glacial Origin of the Lake-basins of Cumberland and Westmorland." 

 —Second Paper. By J. Clifton Ward, Esq., F.G.S. 



The directions of ice-scratches in the various dales having been pointed 

 out, the course of the several main glaciers was described, and it was 

 shown how they must have become confluent in all the lower ground, 

 forming a more or less continuous ice-sheet, which overlapped most of 

 the minor ridges parting valley from valley, and was frequently forced 

 diagonally across them. 



The positions of certain ice-grooves having an abnormal direction 

 were described ; in several cases these cross lofty ridges at right angles 

 to their direction, and generally at passes or depressions along a line of 

 watershed. Most of those noticed had a generally east and west 

 direction, and occurred at varying heights, from 1250 ft. to 2400 ft. 

 The author, while acknowledging the difficulty attendant upon any 

 explanation, was inclined, though somewhat doubtfully, to regard 



