318 
Lloyd says, it could have attained its present position only by passing 
over the almost perpendicular coast. 
The other letter is from Mr. Sherlock, and gives the following 
measurements of two blocks on the Black river :— 
Height. Width. Circumference. Distance from sea. 
Ist block ... 13 feet ... 30 to 40 feet ... 121 feet ..........4.. 350 feet. 
2nd block... 10 — ... 25 feet ......... Length, 41 feet.... 840 — 
Mr. Sherlock adds, there is no coral in the interior, except a 
small bed on the habitation, Le Gentele. 
4. On the mineral veins of the Sierra Almagrera, in the province 
of Almeria, in the South of Spain, by J. Lambert, Esq., F.G.S. 
The Sierra Almagrera extends from the mouth of the Almanzora 
(lat. about 37° 17’, long. about 15° 40’) in a N.N.W. direction for 
twelve miles. Its width is about a mile and a half, and its greatest 
height 1400 feet. It is composed of clay-slate, resting upon mica- 
slate, accompanied by beds of milky quartz, and crossed by numerous 
ferruginous veins containing sulphate of barytes and gypsum. The 
strata of the clay-slate are generally horizontal, but are sometimes 
inclined from 15° to 20°, and even mere, where disturbed by masses 
of greenstone. 
The vein of the Barranco Jaroso was the first discovered, and 
it is now of considerable richness. Its excavations extend more 
than 200 yards in length, with every indication of the lode con- 
tmuing. The direction of the vein is north to south, between 
one and one and a half hours, or 15° to 224° east of north; and the 
inclination is from 65° to 70° east. The breadth of the vein, where 
it was commenced at the surface, was half a yard, but it had in- 
creased to three yards at the depth of forty yards, the point to which 
it had been carried in April 1840. The mineral contents of the 
vein consist of parallel divisions of several varieties of galena, as ery- 
stallized, radiated with an antimonial aspect, brilliant large-grained, 
fine steel-grained, and black, of oxide and carbonate of lead, and 
argillaceous iron ore; carbonate of iron and carbonate of copper 
also occur; and sulphates of barytes and gypsum are abundant. 
Old workings, supposed to have been conducted by the Romans, 
occur in great numbers, principally at the mouths of the Barrancos 
or ravines of Pinalbo del Frances and dela Torre. Quantities of mine- 
timber, decayed iron tools and lamps of clay, have been found in 
them ; but in no case does it appear that gunpowder was used in 
making the excavations. Large heaps of slags and scoria are of 
frequent occurrence; one of the most important being situated be- 
tween the confluence of the Almanzora and the Rambla de Muleya 
at the foot of the little hill Cabéza de las Herrerias (Head of the 
Forges). 
This hill, Mr. Lambert says, presents the aspect of a volcanic 
crater, and has disturbed the tertiary deposits of the neighbourhood. 
He states, that it is an enormous mass of oxide of iron, with a mul- 
titude of veins of sulphate of barytes; and that it is absolutely 
