40 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
Here I may be excused for insisting that no new reading which 
may atise out of a revision of the work of the early explorers of the 
Highlands should be thought to cast any discredit upon them; they 
themselves would have been foremost in disclaiming its finality. I 
am confident that no geologist can have visited the north of Scotland 
without bringing away an intense admiration at the grand results 
attained by those pioneers who did not possess the topographical 
advantages and the refined methods of optical and chemical analysis 
we enjoy. 
In a paper read on the 7th of January, ‘‘On the Voicanie Group 
of St. Davids,” Prof. J. F. Blake gave a third reading of the geolo- 
gical structure of this memorable district, to the effect that Dr. 
Hicks’s three groups or systems—Dimetian, Arvonian, and Pebidian, 
constitute a gradational, continuous series of volcanic rocks of earlier 
age than the ‘* Lower Cambrian Conglomerates.” Prof. Blake there- 
fore is in accord with Dr. Hicks as to their age, and, in the main, 
in accordance with Dr. A. Geikie as to their nature. Mr. Blake’s 
opinions being the outcome of field-work, carried on during a resi- 
dence in the district, claim attention. 
Two short papers by Prof. Bonney, one “On a Section recently 
exposed in Baron-Hill Park, near Beaumaris,” the other “On the 
Rocks between the Quartz-felsites and the Cambrian Series in the 
neighbourhood of Bangor,” were very valuable contributions to our 
knowledge of the Archean rocks of those localities. 
A communication by Dr. Hicks, ‘‘ On the Cambrian Conglomerates 
resting upon, and in the vicinity of, some Pre-Cambrian Rocks (the 
so-called intrusive masses) in Anglesey and Caernarvonshire,” was a 
rejoinder to Dr. A. Geikie’s paper, the first noticed in this retrospect. 
The great value of Dr. Hicks’s paper consisted in the evidence, appa- 
rently unimpeachable and supported by numerous rock-specimens, 
brought forward in proof of the composition of these conglomerates 
largely or mainly of pebbles derived from the granitoid rocks beneath 
them. ‘The identity of the pebbles with the underlying rocks was 
established by Prof. Bonney, by microscopical evidence, in a supple- 
mentary note, which for perspicuity left nothing to be desired. 
In a paper “On the Geology of the South-Devon Coast from Tor- 
cross to Hope Cove,” Prof. Bonney discussed the problem of a tran- 
sition from slaty to foliated rocks. He showed that for this district 
the evidence is against it, and upon clear indications that the foliated — 
rocks had undergone much folding and crumpling after their foliation 
-was completed, and betore the great earth-movements which had 
affected the Palzozoic rocks, he referred the foliated rocks to the 
Archean division. 
Mr. J. H. Collins, in a communication “On the Serpentines and 
Associated Rocks of Porthalla Cove,” stated his belief that an actual 
transition between the rocks mentioned in the title occurred, 
an opinion which he supported by evidence in part drawn from their 
chemical constitution. In the discussion which followed, the con- 
sensus of opinions appeared distinctly unfavourable to the author’s 
views. 
