Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 22, 2025
It is true, as Humboldt has happily remarked, that when we pass to another hemisphere, we see new forms of animals and plants, and even new constellations in the heavens; but in the rocks we still recognise our old acquaintances the same granite, the same gneiss, the same micaceous schist, quartz-rock, and the rest.
This greenstone must, I conceive, be considered as metamorphosed hornblende- slate. The Cerrito, the next highest, but much less elevated point, is almost similarly composed. In the more western parts of the province, besides gneiss, there is quartz-rock, syenite, and granite; and at Colla, I heard of marble.
Northward of Las Minas, the more regular northerly ranges predominate: from this place to near Polanco, we meet with the coarse-grained mixture of quartz and feldspar, often with the imperfect hornblende, and then becoming foliated in a N. and S. line with imperfect clay-slate, including laminae of red crystallised feldspar with white or black marble, sometimes containing asbestus and crystals of gypsum with quartz-rock with syenite and lastly, with much granite.
Some members of the nummulitic and overlying tertiary strata called flysch have actually been converted in the central Alps into crystalline rocks, and transformed into marble, quartz-rock, micha-schist, and gneiss.
Thus, for example, we have seen that in the Apennines, near Carrara, the descending series, where it is metamorphic, consists of, first, saccharine marble; secondly, talcose-schist; and thirdly, of quartz-rock and gneiss: where unaltered, of, first, fossiliferous limestone; secondly, shale; and thirdly, sandstone.
From these peculiarities and from the lens-form of the strata, it is probable that this great pile of strata was accumulated on a shallow and very uneven bottom, near some pre-existing land formed of various porphyries and quartz-rock.
More generally the surface is covered with coarse sand the debris of granite or quartz-rock upon which no vegetable, save the lichen or the moss, can find life and nourishment. In one respect these "Barren Grounds" are unlike the deserts of Africa: they are well watered. In almost every valley there is a lake; and though many of these are landlocked, yet do they contain fish of several species.
While sitting down, in his dilemma, on a quartz-rock, he observed something glittering beside him, and breaking off with his tomahawk a piece of the stone, he carried it home with him as a curiosity. At home it lay for years, till the reported discoveries of gold induced him to offer it for sale to a goldsmith in Sydney.
Some poor miner usually finds a ledge of quartz-rock and digs down the way the ledge goes. He puts up a windlass, worked by hand, over the well-like hole he has dug out, and hoists the ore out in buckets. But he soon finds, as the hole or shaft goes deeper, that he must timber the sides to keep them from caving in, that he must have an engine to raise the ore and a mill to crush the hard rock.
The salinas occur at different elevations above the sea; they are often several leagues in diameter; they are generally very shallow, but there is a deep one in a quartz-rock formation near C. Blanco. In the wet season, the whole, or a part, of the salt is dissolved, being redeposited during the succeeding dry season.
Word Of The Day
Others Looking