dol 
but in the full discussion of which he declines to enter till the whole 
subject is before the Society. 
Jan. 6, 1841.—John Dakin Gaskell, Esq., Norfolk-street, Strand, 
and the Marquess of Bute, F.R.S., Camden Hill, Kensington, were 
elected Fellows of this Society. 
A paper was first read ‘‘ On the Ilustration ef Geological Phe- 
nomena by means of Models,” by Thomas Sopwith, Esq., F.G.S. 
Mr. Sopwith commences by stating, that drawings cannot con- 
vey to the mind a correct notion of geological phenomena where 
more planes than one are required; and that few persons are aware 
of the extraordinary changes which are produced in the combina- 
tions of strata by viewing them on different planes, especially if the 
strata are dislocated; or in undisturbed and parallel strata, of the 
totally different apparent forms which are exhibited on an un- 
dulating surface and in any plane section of the interior. This - 
difference is of great importance in mining plans, where the sur- 
face only in the first instance is accessible to examination, and the 
observer is too apt to infer from it, the subterranean relations of 
the strata. ‘To convey clear notions of these differences Mr. Sop- 
with has prepared a series of hand models, about two inches square, 
formed of layers ef differently coloured woods, and capable of being 
dissected, to a certain extent, vertically, obliquely or horizontally. 
They are also so shaped on the upper surface as to exhibit the un- 
_dulations of the ground. It is not possible to convey verbally, a 
clear notion of the many curious combinations exhibited by these 
models. 
A paper was next read, “ Qn the Geology of the island of Ma- 
deira,” by James Smith, Esq., of Jordan Hill, F.G.S. 
The crust of that island, Mr. Smith states, is composed to the 
depth of several thousand feet of subaérial volcanic matter, erupted 
during the tertiary period; and he adds, perhaps no other volcanic 
region offers more favourable opportunities for investigation. ‘To 
account for its rugged and fragmentary character, it is not neces- 
sary, he says, to have recourse to the supposition that Madeira 
is one of the remains of a vast continent, as there are in the vol- 
canic constitution of the island, and in the action of the mountain 
torrents, sufficient elements to afford data for explaining every 
physical phenomenon. 
‘The igneous rocks composing the greater part of the island, are 
lavas, sand, and ashes, with bombs, lapilli, pumice, volcanic scoriz or 
cinders, tufas and conglomerates; and the non-igneous, the limestone 
of San Vincente, the coal or lignite ef San George, and the sands 
of Canical. 
Volcanic Rocks. 
The lavas are wholly basaltic, containimg numerous crystals of 
olivine ; and they are compact, scoriaceous and vesicular. 
The compact variety occurs in beds or coulées interstratified ih 
the other volcanic products, and in dykes which intersect all the 
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