530 H. HICKS ON THE PRE-CAMBRIAN 
Fig. 4.—Section from the Coast to Bryn-y-garn. 
a a Ss aa 
Cambrian. Dimetian. 
For explanation see fig. 3. 
conglomerates, with rolled fragments of Dimetian up to the size of a 
hazel-nut, or larger. Under the series No. 4 come the Lingulella- 
primeva beds, and good specimens of that fossil have been found 
here, especially in tne bright red beds on the east side of the creek. 
The yellowish sandstones and conglomerates at the base (Nos. 2 & 1) 
have been already referred to. The section, fig. 4, as taken from the 
centre of the Dimetian ridge from the well-known point of Bryn-y- 
garn ina S.S8.W. direction to the extreme end of the headland on 
the west side of Porth-melyn, contains such important and conclusive 
evidence in regard to the questions at issue between the Director- 
General and myself that I submit it with perfect confidence to the 
consideration of any one who is interested in them, and has an 
opportunity of visiting St. David’s. The slides described by 
Mr. Davies in Notes 49-60 were prepared from grits and fine con- 
glomerates found in the series of Cambrian rocks on the west side 
of Porth-melyn. They give abundant proof of what seems perfectly 
clear even on macroscopical evidence, that the material deposited in 
the very earliest Cambrian period in this area was derived from 
such rocks as we now claim to be of Pre-Cambrian age. Almost 
every peculiarity recognizable in the underlying Pre-Cambrian 
rocks, is equally visible in the fragments contained in the overlying 
Cambrian rocks. This, to my mind, is perfectly conclusive proof of 
the Pre-Cambrian age of the rocks I class under the names 
Dimetian, Arvonian, and Pebidian in the St. David’s area. My 
reply to Dr. Geikie might, as stated before, have been confined to 
these facts alone; but asso many statements have been made which 
I cannot allow to pass unchallenged. I propose to deal with each 
of the sections at the points referred to by him; and I shall be 
able. I think, to show how utterly impossible it would be, even on 
purely geological evidence, for the interpretations given by him of 
the conditions shown to be the true ones. Moreover, it is but 
fair to ourselves to state that our conclusions were mainly arrived 
at by critical investigations of the general geological facts exhibited 
by these sections. 
