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tained the geology of Andalucia from the Sierra Nevada of Granada 
to the south ; the 2d described the mountain or rock of Gibraltar ; 
the 3d traced the succession of rocks from the Sierra Morena to 
the south and south-west ; and the 4th described the Sulphur Mine 
near Conil. 
1. In the part of the Sierra Nevada visited by Dr Traill, which 
was at about two-thirds of its height, the only visible rocks were 
mica- slate, in its lower portions approaching to gneiss, on which 
reposed beds of limestone, evidently belonging to the same forma- 
tion as the slate. These rocks, too, form the mountain ranges south 
of Granada, towards the shores of the Mediterranean, near Velez- 
Malaga, where they are covered by a very shining clay-slate without 
organic remains ; and which, in the Sierras Mijas and Bermeja, 
often contain beds of white statuary marble. 
The clay-slate continues along the coast to the south of Malaga 
and Marbella ; but at the Bio Verde it gives place to Old Bed Sand- 
stone, or Devonian strata ; while the rugged mountains to the west 
appear to consist of primary rocks. This Devonian sandstone is 
the fundamental rock of the Sierra Carbonera, the nearest range to 
Gibraltar, and around the bay of that fortress. On this appears to 
repose a limestone, which the author referred to the mountain lime- 
stone. On going westwards from Granada by Loja, Archidona, 
and Antequera, the mountains seem to consist of limestone like 
that of the Sierra Nevada. But on reaching the valley of Teba, 
he found newer rocks, viz., a limestone containing shells, on which 
reposed beds of gypsum and a reddish clay. In this valley is a salt 
lake, evaporated for culinary salt ; and the gypsum often contained 
crystals of rhomb-spar. This valley he therefore considered as 
belonging to the Magnesian Limestone and New Bed formations, or 
Permian system of Sir Boderick Murchison. Farther to the south, 
as about Bonda and Guarroman, a gritty limestone occurs in which 
he found ostracites and other marine shells ; and in the valley of 
Alhama, in Granada, similar limestone occurs, with those shells, 
mytilites and corals. Both formations he refers to the Oolite 
system. 
2. The author described the geology of Gibraltar, which he 
referred entirely to the true mountain limestone, and illustrated his 
remarks by specimens of the solid rock, of the fibrous limestone, 
and of the calc-sinter deposits containing bones. 
