304 Royal Geological Society of Cornwall. 
and, consequently, as demonstrating the secondary nature of our 
Cornish slate. -Mr. Rogers is of opinion—and it would seem 
justly—that these supposed organic impressions are mere va- 
rieties of structure of the slaty matter itself. 
5. A paper by Miss Hill, of Barnstaple, ‘ On the Discovery 
of Hydrargyllite.”” From this communication it appears that the 
brother of Miss Hill, late surgeon in Barnstaple, and not Dr. 
Wavell, as is commonly believed, was the original discoverer of 
this mineral. 
6. A paper by Dr. Forbes, “ On the Geology of that part of 
Cornwall lying to the westward of Hayle and Cuddan Point ;’ 
illustrated by numerous specimens, and by an elegant geological 
map, and many drawings by Mr. Moyle, assistant secretary. On 
the present occasion Dr. F. had only time to read that portion of 
his paper which treated of the granite of the Land’s-End district, 
and of the slate for mation, observable on the shores of the pa- 
rishes of Burian Sennen, St. Just, Zennor, Towednack, St. Ives, 
and Lelant. In this paper the author denied the stratification of 
the Cornish granite; stated the slate formation of the district, 
which he described to consist of the following five rocks, horn- 
blend rock, greenstone, felspar rock, slaty felspar, aid clay slate ; 
and expressed his belief of the contemporaneous origin of these 
rocks, and the fundamental granite. As an irresistible argument 
in favour of this opinion, and as of itself subversive of the Hut- 
tonian theory, he adduced the frequent instances observable on 
the Cornish shores, of granite veins originating in the same rock, 
intersecting each other, and exhibiting at the point of intersec- 
tion the appearance called a shift or heave. 
7. Two very interesting papers “On the Tin Trade of the An- 
cients ;”,—one by the Rev. Mr. Greatheed, the other by the trea- 
surer, H. Boase, Esq. ‘The latter gentleman brought forward many 
ingenious arguments in support of a somewhat heterodox opinion 
which he holds, respecting the knowledge of Britain possessed by 
the Ancients. He denies that Cornwall was ever visited by the 
Phoenicians, and maintains, that if any islands denominated Cas- 
siterides really did exist, they certainly formed no part. of the 
present British dominions. 
Besides the papers above mentioned, there were some before 
the Society that were not read. Notices were also delivered in by 
Mr. Joseph Carne, of the quantity of tin and copper raised in 
Cornwall, Ireland, and Wales, during the year ending June 30th, 
1818; and several catalogues of geological and other specimens 
were presented to the Society by different gentlemen. 
In the course of the meeting Lord De Dunstanville took oceasion 
to notice the presentation of a piece of plate, value 150 guineas, 
to Dr. Paris; to whom, also, thanks were voted for superintend- 
ing 
