﻿Reports and Proceedings. 35 



IV. — The Puzzlk of Life and How it has been Put Togethee. 

 A Short History of Vegetable and Anibial Life upon thI'^ 

 Earth from the Earliest Times, including an account of Pre- 

 historic Man, his Weapons, Tools, and Works. Bj Arthur 

 Nicols. pp. 148. (London, Longmans & Co., 1877.) 



ANY attempt to put the leading facts of a science within the com- 

 prehension of children, and of grown-up persons whose educa- 

 tion has not fitted them to grapple with technical terms, must be 

 fraught with considerable difficulty. Science, as often observed, has 

 a language of its own, and it is frequently impossible to translate it 

 in so simple a form, that all who read may understand. The present 

 little work, however, which is specially addressed to children, is 

 written in so pleasant and easy a style, and its descriptions of life 

 on the earth are on the whole so simple and accurate that we can 

 heartily recommend it to the attention of those who seek such a 

 guide. The illustrations are good and the general appearance of the 

 book such that it may compare most favourably with other primers 

 of geology. H. B. W. 



Gteological Society of London. — November 22nd, 1876. — Prof. 

 P. Martin Duncan, M.B., F.R.S., President, in the Chair. The 

 following communications were read : — 



1. '' On the Pre-Cambrian (or Dimetian) Eocks of St. David's." 

 By Henry Hicks, Esq., F.G.S. 



Referring to the ridge of pre-Cambrian rocks, which he described 

 in a former paper as running down the St. David's promontory, and 

 as previously supposed to consist of intrusive syenite and felstone, 

 the author stated that he had now found it to be composed exclusively 

 of altered sedimentary rocks of earlier date than the Cambrian de- 

 posits, the conglomerates at the base of which are chietiy made up 

 of pebbles derived from these rocks. Recent investigations had led 

 him to the conclusion that the main ridge was composed of two 

 distinct and decidedly unconformable formations, the older of which 

 composed of quartzites and altered shales and limestones, con- 

 stituting the centre of the ridge, has a N.W. and S.E. strike, and 

 dips at a very high angle ; whilst the newer series, consisting of 

 altered shales, and having at its base a conglomerate composed of 

 pebbles of the older rock, has a strike nearly at right angles to that 

 of the latter. For the former he proposed the name of Dimetian, and 

 for the latter that of Pebidian. The author indicated the points of 

 resemblance between these pre-Cambrian Eocks and the Laurentian 

 of Canada, the Malvern Eocks, and others in Scotland and else- 

 where, but thought it safer at present to abstain from attempting 

 any definite correlation of them. The exposure of the older, or 

 Dimetian, series led the author to ascribe to those rocks a thickness 

 of at least 15,000 feet; the upper or Pebidian rocks, which flank both 

 sides of the old ridge through a great portion of its length, are 

 apparently of considerably less thickness, but they are in most parts 



