76 
Mr Baird on the Geology qf the 
of the west side of the rock. The length of the rock from N. 
to S. may be about S J miles ; its breadth from W. to E. from 
half a mile to above a mile ; and its height about 1000 feet 
above the level of the sea. The top of the rock is a long nar- 
row ridge, running N. and S., the west side sloping down to the 
town and bay ; the east side, from its rugged, perpendicular 
front, almost inducing the opinion, that Gibraltar Rock, as it 
now exists, is only the half of* a large hill, the east side of which, 
in some great convulsion of nature, has been torn asunder from 
the other, and precipitated into the Mediterranean. 
The view from the top of the Rock of Gibraltar, the Mount 
Calpe of old, in a clear day, is most magnificent. To the east, 
the Mediterranean stretches out before us as far as the eye can 
reach ; and on either side its lofty shores, the mountainous coast 
of Africa on the one hand, and, on the other, the more beauti- 
ful perhaps, but scarcely less hilly coast of Europe, both gra- 
dually receding from each other, to form, as it were, a broader 
basin for the Mediterranean ; the village of St Roche, to the 
north, beautifully situate on the top of a gently sloping hill ; 
the Bay of Gibraltar, and town of Algeziras to the west, and 
to the south the sister pillar, the lofty Mount Abyla, and her 
neighbouring mountains. 
The Rock of Gibraltar is composed of limestone, of which 
there are two principal varieties, one, forming the great mass of 
the hill, hard, fine-grained, with a splintery or conchoidal frac- 
ture, possessing considerable lustre, and generally of a light- 
grey colour, sometimes also dark, sometimes nearly white, and 
in one part of the hill, where it is quarried as a marble, occur- 
ring beautifully variegated. This limestone is stratified, and 
near the top of the hill, as is well seen, the strata run from near- 
ly N.E. to S.W., and inclining to the S.W. at an angle of 60° 
or 70°. The other principal variety is a conglomerate or brec- 
ciated limestone, formed of -the debris of the former, connected 
by a red calcareous basis^ and capping round the other central 
mass. This conglomerate variety appears to be still forming on 
the hill. Besides these, there occur two beds of a flinty slate 
rock, both very much decayed, and one of them containing nu- 
merous round and angular pieces of limestone. These beds ap- 
