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Remember the Rainforest 1

 

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of Rio das Contas - that is, the formation of the soil is a bed of fine mica schist,

Mica schist

with crystalline quartz granulation

Rose quartz crystal

and many white, or light brown, mica straws. To an even greater extent, primitive ardosia arises, transitioning to mica schist, which runs in the direction N. to S., and declines east at an angle of about 40 °. It appears here dark green, with laminate texture and containing even crystals of magnetite; sometimes it is

Chlorite shale

flesh color, light or bluish, having a larger or smaller portion of chlorite shales mixed. Dark, luminous, fine-grained, schist amphibolite strands, deposits of

Diabase

compact diabase and early gray limestone, in which very small grenades and many chlorite shales are mixed, are found in this formation, which occurs near

Fazenda Aldeia, where we made the observations, in a series of low hills.

Grenade or garnet

In the partly artificially deepened plain between these hills and the Salitre River, to an extent of about 60,000 square feet, and along the Salitre River in many similar places, salt is extracted from the ground, which lies in layers. many inches thick on the stone. This earth is hollow yellow, thin, sometimes oily to the touch, and equally mixed, with both plant residues and rolled pebbles, brought on by the flooding of the river. Fractures of quartz, amphibole and breaches already observed in Fogo Island are more abundant in this land. As soon as the rain or the flood dissolves the saline part and the warmth of the sun comes over, this leach evaporates, whitish crystallized saltpeter appears, which crumbles under the feet, sometimes denser, sometimes thinner; In it, the hollow rectangular pyramids and the salt cubes can be distinguished with naked eyes.

Saltpeter

The thinner is the water layer, the faster is the evaporation in one place, and the sooner this deposit appears, which is why we could only observe it in the most abundant places, already worked, and also in the footprints of cattle. As is common with cooking salt on land and sea, here too it does not occur alone, but accompanied by plaster, calcium hydrochloride and magnesia hydrochloride; sometimes saltpeter is also found among the efflorescences. The area of this salt production is not limited to the region of the Salitre River, but extends from

these southernmost salt pans, over the great valley of the Sao Francisco River, to Urubu Village, over three degrees latitude, and in a width of 25 to 30 leagues. To the east, this district is bordered by the continuation of the Serra das Almas (Serra da Chapada, Morro do Chapeu, etc.) and several isolated limestone mountains that, in Minas Gerais, contain large saltpeter caves. The Paramirim, the Rio Verde, the Salitre River, which are born in these mountains, and join the Sao Francisco, all carry salt particles. In the west,

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