Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1860* edition. Excerpt: ...character being caused by the diffusion of oxide of iron. A beautifully crystallized form of calcareous spar, not uncommon, is composed of an aggregation of long slender translucent crystals, of a bright amber colour, and breaking with the Geo. Trans/ second series, vol. iv. p. 255. f Fissures in rocks of volcanic origin, are supposed to be occasioned by their contraction, while passing from a heated to a cool state. Their occurrence in stratified rocks may arise from the violent tension to which the solid strata would be subjected during its upheaval, a tension that could only be relieved by a rent or fracture. In the latter instance, it is not uncommon to rind the face of each side of the opening either polished or scratched from the rubbing together of the two sides. Another result is the horizontal displacement of the strata, i. e., a sinking or depression of the beds, on one side of the fracture, which sometimes amounts to several hundred feet. The continuity of the strata in the Portland fissures is but little interrupted. J In the caves of Matlock, they are formed of sulphate of barytes. rhomboidal fracture peculiar to crystallized carbonate of lime. Colourless crystals of the variety called dogtooth-spar are also found. Stalagmite (from araKayfia, a drop).--When the water drops too quickly from the roof to allow of the formation of a stalactite, the deposit takes place on the floor on which it falls, and is then called stalagmite. In this latter form it is known by the Portland quarrymen as sugar-candy, cauliflower, &c. It is not uncommon to find stalactites that attain such a length as to become united with the stalagmite; and thus by the gradual accumulation of infiltrating matter, as in the manner here pointed out, the...
