
TRANSACTIONS OF THE SECTIONS. 5q 
The author is engaged in making out a list of the organic remains of Cornwall, 
which he has found, and are now in his possession. 
The author has found a conglomerate in Gorran, in which are large rolled masses 
of limestone inclosing Orthoceratites, Crinoidea and corals, as well as detached corals 
in the softer parts. 
A large specimen was exhibited from the quartz rock of Great Peraver Goran. It is 
rather abundant there, and covers the sides of some of the blocks four or five feet over: 
some of the tubes are more than a foot in depth: it appears to be very much like the 
Sabellaria alveolata (recent) in its habit. The upper part of the tubes is funnel-shaped 
and filled with clay-slate: it is also found sparingly in the quartz rock of Caerhayes 
and Gerrans Bay. Generally they are much distorted. 
On the Granite and other Volcanic Rocks of Lundy Island. 
By the Rev. D. Wituams, F.G.S. 
Mr. Williams described this island as a mass of gray granite, three miles long by 
about half a mile wide, flanked at its south-east angle by slate rocks, which, beyond 
the immediate influence of the granite, had an east and west strike, and extended for 
about half a mile. The circumstances attending the granite were altogether unlike 
those of any granite mass of Devon or Cornwall. The usually abundant evidences 
of the processes by which the bounding rocks had been reduced and converted into 
granite in the vast volcanic laboratories, were all absent, He could not discover a 
vestige of a granite vein, nor could he observe anywhere a trace of gneiss, mica, or 
chiastolite slate. In Devon and Cornwall he had often observed that the mineral 
characters of granite, especially in the veins, varied with the lithological constitution 
of the sedimentary or other rocks, out of which it had been derived, and with which 
it was so intimately associated. Besides, the incorporation, the welding, as it were, 
of the granite in veins with the sedimentary rock, was commonly so perfect that it 
was altogether impossible to separate them. Now at Lundy Island, although he had 
repeatedly tried at several visits, he never had succeeded in detaching a specimen of 
slate united with either the granite, trap, or porphyry, though it was considerably 
indurated and altered by them, and otherwise in precisely the same condition as the 
slates in Cornwall. He proposed, in reference to the agency of heat on rocks con- 
tiguous to igneous masses, to distinguish between active and inert heat—the former 
exerted in reducing the minerals to fluids, the latter simply indurating and otherwise __ 
partially altering them. The junctions of the slate and granite at Lundy, which 
were very clearly exposed on the north-east and the south-west, evidenced nothing 
more than the operation of inert heat: the granite there was manifestly older than 
the slates, the slates were older than the traps, and the traps which traversed slate 
and granite were older than the porphyries, which cut off and shifted the traps. 

On the Geology of Corfu. By Captain Porrtock. 
Extract from a letter to Professor Phillips, dated July 9, 1843 :—‘‘ The secondary 
limestone here is remarkable: some of it has strongly the aspect of our Irish 
hardened chalk, and abounds in flints; but other portions resemble some of the 
varieties of Irish mountain limestone. Fossils are not abundant; but I have obtained 
two species of Terebratula from the little fortified island of Ordo, close to us, and 
they appear to resemble cretaceous species,—certainly not mountain limestone,— 
though Dr. Davy in his description of these islands seems to consider it the latter. 
By the autumn I hope to settle this question completely, which will decide the age 
also of a remarkable conglomerate, containing pebbles of the limestone and flint, and 
probably tertiary, though called secondary by Dr. Davy.” 

On the Phenomena and Theory of Earthquakes, and the explanation they 
afford of certain facts in Geological Dynamics. By H. D. Rocerrs, Pro- 
Sessor of Geology in the University of Pennsylvama, and W. b. Rocrrs, 
Professor of Natural Philosophy in the University of Virginia. 
This communication was prefaced by a recapitulation by Mr. Lyell of Messrs. 
Rogers’s observations on the structure of the Appalachian chain of mountains [See 
nd 
