35 
Reports and Proceedinys. 
IV. — Töe Puzzle of Life and How it has been Put Together. 
A Short History of Vegetable and Animal Life upon tiie 
EaRTH FROM THE EaRLIEST TlMES, INCLUDING AN ACCOUNT OF PrE- 
Historic Man, his Weapons, Tools, and Works. By Arthur 
Nicols, pp. 148. (London, Longmans & Co., 1877.) 
A NY attempt to put the leading facts of a Science within the com- 
prehension of children, and of grown-up person s whose educa- 
tion has not fitted thern to grapple with teclinical 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, wbich is specially addressed to children, is 
written in so pleasant and easy a style, and its descriptions of life 
on the eartb are on the whole so simple and accurate that we can 
heartily recoramend 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. 
ZEaZEHPOIRTS JkHsTID PEOCEEDIUG-S. 
Geological 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) Rocks of St. David’s.” 
By Henry Hicks, Esq., F.G.S. 
Refen'ing 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 chiefly 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 Rocks and the Laurentian 
of Canada, the Malvern Rocks, 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 
