'Transactions of the Bombay Geographical Society, from September 1850 to June 1852. Edited by the Secretary. Volume X.' [‎159] (292/458)

ARABIAN AND AFRICAN VOLCANOES*
entw * tin J
' ,mson suppostii!
¥m of »iij
on tlie easIcnJ
'as shattereJiu
liern pass, y
era side of tM
se \\m I ct
this wliicliiei
eet, ami tlienk
en thesideoflS
of the cratensi:
Jie most magnltf
. • 1'
ice, five A i»t
i in most placesf
r, and fullof^
a Gothic cai*
• to poiiiMsii:
and oonjeaH 1
r. On
,,_to the |«
jst na™^ ®
ic ashes are!,#!
159
amongst the crevices of the rocks, these generally abounding, as does
the surface all around, with sea shells in a state of great decay, to all
appearance borne up by the volcano on its last emergence from
the deep.
The minerals found at Aden are very numerous. We have almost
every variety of lava, compact, earthly, vesicular, amygdoloidalporphy-
etic, and obsidian in all its forms, from dull coarse green and bluish-
green to beautiful jet black. Pumice is found, but is not plentiful. It
is mostly of a dark redish brown colour, and is heavier and more coarse
in its texture than the mineral of commerce, and less suited for the finer
purposes of the polisher. Brimstone is sometimes found, but rarely.
Bock crystals in veins, nests, and crusts, are very plentiful everywhere.
On many parts of the volcano chalcedony in various forms abounds ; in
some cases it appears in thin crusts, in button-shaped encrustations
or in drops or studs, occasionally covered over with delicate rock
crystals. They are of a beautiful bluish white, and take a prominent
place in any cabinet. On these are occasionally found small crystals
of purple fhior spar, from the size of a mustard seed to that of a sweet
pea. Carbonate of lime appears as calcareous spar, frequently filling
veins and cavities, as a slightly crystallised veined variety of marble of
various tints of brown, exactly like the Gozo marble seen at Malta,
ami the portions of the Bock of Gibraltar from which ornaments are
mostly cut. Sulphate of lime is found in veins in the form of
beautiful fibrous gypsum, semi-transparent, and colourless. It also
occurs in plates, specimens of all the minerals here described I have
in abundance in my own cabinet—they have been mostly collected for
me by Dr. Maleolmson, Mr. Mayes, and Mr. Adie, the duration of
my own visits to Aden precluding me from procuring the rarer
minerals.* Bight across the bay to the eastward, at a distance of five
miles are the magnificent remains of another crater, called Gibbel
Hassan. It is nearly the same size and form as Aden, but rests on the
* The following author-* Iiftv» been Oonsu fed in preparing these Observations:—
Bruce’s Travels. Lands of the B ble, by the Rev. Dr W Ison, voi. i p. 9—25. name's Deg-
cri, non of Peninsula, Shores, and Climate 1 ond«»n 'Irmi ., vols. ix. and xv. Salt's
account of, Travels. Medical Topograph\ of, Bombay Times, January 16, 18 9. Cor. Ind.
Rev. rol. iii, i onn ay Med. Trans., p. 666. Ulcer.-, Dr. Campbell on Ibid, repiinted Ind.
Jour, of Med. and Pby Science. F<»sier, Bombay Engineers, Description of.—bom nay
Geog. Trans., 1839. Description of, by Rev Dr. Duff. Dome and Foreign Missionary
Record, 1846, Bombay Times, 1840. p 467. Mignon, Lieut. Colonel, account of.—Almanac
1842. .^n. Mr. F. Burr’s account of, Lond. Geol. Tans., 1841, vol. vi. p. 30.—Bombay
As. Trans., yob i., p. 84. Ind. Rev., vol. 6, 1842. Malcolmson Dr., Geology of, London as