319 
heney-combed by old excavations in the barytes veins, the contents 
of which, he believes, were used as a flux in smelting the argen- 
tiferous minerals. The tertiary beds at this locality consist of clays 
resting upon conglomerates, and are all charged with iron. They 
are stated to contain also “‘ ferruginous and jaspery dendrites,’’ veins 
of felspar and crystals of barytes. 
A tertiary formation extends from the foot of the Sierra Almagrera 
to the Sierras de Filabres, de Alhamilla’ and Cabrera. The upper 
part consists of an arenaceous conglomerate alternating with marls, 
and beds of quartz and other pebbles of various sizes. The clays con- 
tain gypsum and sands very similar to those of the vicinity of Paris ; 
and numerous organic remains, belonging principally to the genera 
Ostrea, Pecten, and Dentalium; likewise corals. The formation is 
disturbed in many parts by protruded masses of greenstone; also 
by porphyries, trachytes and basalts, which are stated to present 
very singular phenomena. Gneiss projects above the tertiary strata 
in many places. 
The paper was accompanied by specimens of galena, of which the 
following analyses are given in the paper itself : — 
SpPecimenyWorlelarcceceess 70°38 per cent. Lead 1°05 per cent. Silver 16 0z. per gal. 
a 2, Radiated 62:1 : 0°65 10 
8. Black ... 22°25 ————___ 9-325 —— 5 
About 400 tons of numbers 1 and 2, have been extracted from 
the mine during the months it had been worked ; and the produce 
about the time the paper was written was fifteen tons a day. 
5. A notice on the Sierra de Gador, and its lead mines, by Josias 
Lambert, Esq., F.G.S. 
The Sierra de Gador, celebrated for its lead mines, is situated be- 
tween the Sierra Nevada and the Mediterranean. Its length from 
west to east is nearly forty miles; its breadth varies from five to 
ten miles, and its highest point,—the Collado de los Valientes, 
near its western extremity,—is upwards of 6000 feet above the sea. 
From that point eastward, the height gradually decreases till it 
is reduced near the Almeria to the level of that river. The 
southern face is precipitous, and from its base to the Mediterranean 
extends the tertiary plain of Dalias. The western flank is also pre- 
cipitous, but the northern face rises more gently from the river Al- 
meria, which separates the Sierra de Gador from the Sierra Nevada. 
The principal mass of this range of mountains is composed almost 
exclusively of a limestone, considered by Mr. Lambert to belong to 
the lowest of the transition rocks, because its stratification is in 
general conformable to that of the nucleus of the Sierra Nevada, 
and because it is believed to contain no organic remains. It is of a 
grey or dark colour, and of a compact or finely grained texture, but 
it is sometimes, though rarely, friable. It passes downwards by 
alternations and transitions into clay-slate, talcose or mica-slate 
and.in the upper part, it is connected with breccias and limestone 
conglomerates. 
