428 Correspondence. 
The Club met for dinner in the ‘Tower’ on the top of Sweeney 
Hill. After dinner, several new Members were elected, and it 
was decided, in addition to the Meeting intended to be held at 
Llangollen in August, to have an excursion to Westbury in Sep- 
tember. A visit was then paid to the quarries in the Millstone 
Grit on the west side of Sweeney Hill; and in the one nearest to 
the Tower, the line of fault to which the hill owes its elevation 
was well seen. In the next, the uppermost beds of Grit were seen 
dipping unconformably under the Coal-measures; and from some 
of the highest beds were obtained numerous specimens of Productus 
semireticulatus, var. Martini, associated with Calamite-stems and 
a unique example of a large Annelid, together with many Fucoids. 
Some attention was next paid to the ‘ Pockets’ which occur in the 
thick Sandstone-beds. The character of the beds downwards to the 
subjacent Mountain-limestone was noticed as fully as time would 
allow, and the horizon of the various fossils hitherto discovered was 
pointed out by one of the Members. ‘The branch railway before 
referred to cuts through the formation in a line nearly coincident 
with its dip; and the Members present were able to traverse the 
whole series, and to verify the fossiliferous nature of the lower 
beds. Thus terminated a very pleasant and instructive excursion. 
—D. €. D: 
CORRESPONDENCE. 
—>—_——_ 
To the Editor of the GEOLOGICAL MAGAZINE. 
Dear Sir,—A few days ago, I observed at the Talargoch Mine, 
near Prestatyn, Flintshire, a very curious, and, as I believe, unusual 
form of quartz, which, I think, is worth noticing in the Magazine, 
The mine is situated at the foot of a bold escarpment of Mountain- 
limestone forming the western termination of one of the great lime- 
stone ranges that run through Denbighshire and Flintshire. Most 
of the lodes occurring in the black shales and limestones at the base 
of the Carboniferous series run ENE. by WSW., and contain 
sulphurets of lead and zinc in a matrix of quartz and cale-spar. One 
of the lodes running east and west, nearly vertical, and from three 
to six feet in width, is almost entirely occupied with silicious sand 
of the most perfect purity and lustrous whiteness. Just at the side 
of the lode, at its junction with the limestone, a little calcareous and 
quartz-spar occurs, which, in a few places, runs into the body of the 
lode ; and an isolated nodule of spar, with a little galena, is occasion- 
ally found: but otherwise the whole lode is a mass of homogeneous 
and fine-grained sand, soft enough to be friable under the miner’s 
‘pick,’ and when dry quite incoherent, breaking up into fine dusty 
particles. A gradation between this white sand and the regularly 
crystallized quartz is occasionally met with in the form of white 
saccharoid spar ; and it would be difficult to determine whether this 
sand-lode is merely decomposed quartz, or a segregation of silica 
that had never attained complete crystallization. The lode near the 
