Geological Excursion to Guildford. 331 



Venezuela, the pre-Cretaceous age of wliicli is proved by their being 

 overlain by unaltered Neocomian beds. Indulging in speculation as 

 to the age of these auriferous rocks, the author sought, by analogy of 

 their mineral contents and their lithological similarity to certain 

 auriferous and associated strata in Bolivia, to establish their Silu- 

 rian age. 



Skirting the Orinoco and abutting against the escarpment of the 

 Itacama Mountains, were described the ''Llanos" sandstones and 

 conglomerates, derived from the metamorphic series. These beds, 

 which were referred to the Upper Miocene, are in their easterly 

 extension lignitiferous and asphaltic ; and as the basin of the Ori- 

 noco is excavated in them, it was contended that the present river 

 could have played no part in the accumulation of the materials from 

 which the asphaltic deposits have been supposed to have originated. 



5. " On the Nature and Cause of the Glacial Climate." By Jos. 

 John Murphy, Esq., F.G.S. 



The author cited the conclusions arrived at by Mr. CroU as to the 

 causes of Glacial climate, and stated his agreement with them, ex- 

 cept in one instance ; he maintained, in opposition to Mr. Croll, that 

 the glaciated hemisphere must be that in which the summer occurs 

 in aphelion during the period of greatest eccentricity of the earth's 

 orbit. He showed that a cool summer had more to do with the 

 prevalence of glacial conditions than a cold winter, and referred to 

 several phenomena furnishing arguments in favour of his opinion. 



Discussion. — Prof. Ramsay remarked that Prof. Dana and himself had both re- 

 ferred the origin of many fjords to the same cause as the author. 



GEOLOGICAL EXCURSION TO GUILDFORD. 



Geologists' Association. — A geological excursion of the members 

 and friends of this Society, accompanied by some of the students 

 belonging to Prof. Morris's class at University College, took place 

 on June 2nd, for the purpose of examining the geology and other 

 natural features of the beautiful neighbourhood of Guildford. The 

 excursion was under the superintendence of Prof. Morris, the Presi- 

 dent, who availed himself of the very valuable co-operation and 

 guidance of Mr. C. J. A. Meyer, formerly resident at Godalming, 

 and long interested in the district, and whose published memoirs 

 have largely assisted in elucidating its geology. At Guildford the 

 party was met by Prof. Kupert Jones, from the Eoyal Military 

 College, Sandhurst, accompanied by several friends and officers of 

 the Eoyal Staff College. The chief object in view in this excursion 

 was the examination of the several kinds of strata foi-ming the hills 

 and vales in the vicinity of Guildford, Shalford, and Chilworth, 

 especially as to the relative positions of the several beds of chalk, 

 clay, and sandstone, which, lying either horizontal or in more or less 

 inclined positions (in some places turned up almost on end), come to 

 the surface in succession, and form flat, raised, or hollow ground, 

 according to their power of resisting the wear and tear of frost, rain, 

 rivers, and other denuding agencies that have worked over the land 

 during the countless ages looked back into by geologists. 



