558 ON THE FRE-CAMBRIAN ROCKS OF PEMBROKESHIRE. 
Both of these rocks (Nos. 82, 83) present a distinctly gneissic 
aspect, more marked in No. 82, which, especially, bears a remarkable 
resemblance to some old gneisses. 
EXPLANATION OF PLATE XXIV. 
Geological Sketch of the older rocks of the St. David’s district. 
Discussion. 
The PresrpENT, in inviting discussion on this important paper, 
expressed a hope that Fellows would limit their remarks to the 
points raised in connexion with the St. David’s district and not 
attempt to consider the general theories of metamorphism. He also 
trusted that the question would be discussed in a calm and scientific 
spirit. 
OMe Torrey said that the Director-General of the Geological 
Survey went to St. David’s quite prepared in large part to accept 
Dr. Hicks’s views. He stated that Sir Andrew Ramsay’s earlier 
views were certainly much more correct than the later. He ad- 
mitted that if the statements now made by Dr. Hicks as to the 
presence of undoubted Dimetian fragments in the conglomerate 
could be substantiated, the main question was settled. He adverted 
to the fact that this evidence had not been brought forward at the 
reading of Dr. Geikie’s paper. He insisted that the specimens now 
exhibited were exceptional in character, and that the Cambrian 
conglomerate is mainly a quartzose conglomerate and not made up 
of Dimetian materials. He admitted that some small fragments 
in the conglomerate did resemble Dimetian. He accepted the 
apparent unconformity in some places between the Cambrian and 
Pebidian; but this was explained by Dr. Geikie as due to con- 
temporaneous erosion. The sections could only be judged by those 
who visited the country and compared the interpretations of Dr. 
Hicks and Dr. Geikie. He remarked on the peculiar fact of Dr. 
Hicks finding everywhere in small areas no less than three uncon- 
formable divisions of the Archean series. This point had been 
insisted on by Prof. Blake. He alluded to the views of MM. Renard, 
Wichmann, and Zirkel as confirming those of Dr. Geikie. With 
respect to the paper of Mr. P. Frazer, Dr. Geikie was not responsible 
for it, for that gentleman left the English surveyors before their work 
was concluded. 
Prof. Hurt had not visited the district, but he insisted that the 
field-work at St. David’s had been done by such excellent geologists 
that he could not believe that it was to be set aside on such evidence 
as that brought forward by Dr. Hicks. He thought that the sup- 
posed inclusion of fragments of the older rocks might be accounted 
for by the breaking up-of lavas as they flowed over the bottom of the 
sea, and the inclusion of the fragments in the still flowing mass. 
Principal Dawson remarked that some Canadian geologists had 
objected to the use of the terms Pebidian and Dimetian for the 
Pre-Cambrian rocks described by Dr. Hicks, and thought they 
