ON THE PRE-CAMBRIAN ROCKS OF PEMBROKESHIRE, 559 
should have been named Huronian and Laurentian, since they 
resembled these rocks so much in mineral character. After hearing 
the paper and the discussion which followed, he thought Dr. Hicks 
might be excused for inventing new names rather than identifying 
the disturbed and much disputed rocks he had described with the 
widely distributed and indisputable Pre-Cambrian rocks of Canada. 
The questions involved as to these beds were both stratigraphical 
and lithological. The sections exhibited showed great disturbance 
and complexity, except two of them, which appeared to show 
distinct uncontormable superposition of the Cambrian on the Pebi- 
dian. He would ask Dr. Hicks to,explain if these cases were really 
as plain in nature as they appearedin the diagrams. With reference 
to lithological questions, the most important and, indeed, devisive 
fact was the occurrence of pebbles of Pebidian and Dimetian rocks 
in the Cambrian conglomerates. In the case of mere grits, quartz 
sand and fragments of felspar went no further than to indicate deri- 
vation from granitic rocks of some kind. ‘The occurrence of actual 
pebbles was, however, a decisive point. With reference to the Pre- 
Cambrian rocks of Canada, which had been referred to, he would say 
that, though the great Laurentian and Huronian series were clear 
and undisputed, there were cases where rocks haying many of the 
mineral characters of these series were so involved with folded and 
partially altered Palaeozoic sediments that they presented as great 
complexity as any in Wales or Scotland, and had led to much con- 
troversy. As an old member of the Society, but one who could very 
seldom be present at its meetings, he desired to express his gratifica- 
tion in witnessing its continued life and activity, and its energetic 
discussions of matters of geological fact, and more especially its 
prosecution of the great questions involved in the itholozy and 
stratigraphy of the old crystalline rocks. 
Prof, T. McK. Hueues said the principal question at issue was 
whether the so-calied Dimetian was older than or intrusive in the 
Pebidian and Cambrian. He thought that Dr. Hicks had somewhat 
unwisely accepted the challenge of the Director-General to allow 
the settlement of the question to depend upon the finding of frag- 
ments of Dimetian in the base of the Cambrian, as he did not believe 
that the little particles.of felspathic rock in the grit would carry 
conviction. All the junctions between the Cambrian and the 
Dimetian are faulted ones. At the one point where the junction 
could be best studied, there was no proof of contact-metamorphism 
but only of crushing. He thought Dr. Hicks had gone far towards 
demonstrating the truth of his views concerning the principal 
question. 
The Presrpent could not admit the validity of the rule which 
Mr. Topley sought to establish, that the reply to an attack should 
be given immediately. He had seen all the slides referred to by 
Dr. Hicks and Mr. Davies, and was bound to say that they bore out 
the views of the author as to the presence of fragments of Dimetian 
rock in the grit of the Cambrian. He fully agreed with ell the 
more important conclusions at which Mr. Davies had arrived. 
PL Pe 
