57$ Geological Society : — 
ean only be in situ and must have once formed part of a large 
continuous mass, and that the bulk of this mass must have lain to 
seawards of the present coast-line. 
February 5th.— Sir Archibald Geikie, K.C.B., D.C.L., Sc.D., 
Sec.R.S., President, in the Chair. 
The following communications were read : — 
1. 'On Antigorite and the Val Antigorio, with Notes on other 
Serpentines containing that Mineral.' By Prof. T. G. Bonney, 
Sc.D., LL.D., F.R.S., F.G.S. 
It is by no means certain, as the author ascertained after his 
joint paper with Miss Raisin, published in 1905, that the first- 
described specimen of antigorite was really found in the Val 
Antigorio. So last summer he visited that valley, in company 
with the Rev. E. Hill, and after an examination, of which he gives 
an account, came to the conclusion that the rock most probably 
does not occur there in situ, though it is found in pebbles, etc. 
from tributaries. 
He next describes other specimens of antigorite-serpentine, 
examined since 1905 : some from New Zealand, kindly sent to him 
by Dr. J. M. Bell, and others obtained in the Saasthal, especially 
from the Langefluh : giving further particulars about specimens in 
the National Collection at South Kensington and in the University 
Collection at Cambridge. 
He then discusses the origin of the mineral. Pressure is 
apparently essential ; certainly it can be formed from augite, and, 
though he has not discovered residual olivine in his own rather 
numerous specimens, or typical antigorite in Alpine bastite-serpen- 
tines, he finds indirect evidence of its coming from this mineral, 
proofs of which are given by F. Becke, M. Preiswerk, and J. M. 
Bell. If, however, we suppose the former existence of two types 
of peridotite in the Alps, as at the Lizard and in the Vosges, and 
pressure sometimes to have preceded, sometimes to have followed 
serpentinization, we can account for the apparent conflict of 
evidence. 
2. ' The St. David's-Head " Rock-Series " (Pembrokeshire).' By 
James Vincent Elsden, B.Sc, F.G.S. 
The St. David's-Head and Carn-Llidi intrusions are of complex 
composition, ranging from a basic biotite-norite to an acid quartz- 
enstatite-diorite, and finally to soda-aplite. Throughout all the 
types, except the last, there is a high magnesia-percentage. The 
extreme types sometimes pass abruptly one into the other, and at 
other times they are mixed in various proportions. They do not 
represent a composite intrusion, but simultaneous intrusions of an 
