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It so happens that calcareous skeletons, exactly similar to the Globigerinae of the chalk, are being formed, at the present moment, by minute living creatures, which flourish in multitudes, literally more numerous than the sands of the sea-shore, over a large extent of that part of the earth's surface which is covered by the ocean.
The specific gravity of ordinary limestone varies from 2.6 to 2.75; pure Carrara marble was found by Sir H. De la Beche to be 2.7. The great accumulation of loose calcareous particles, lying on the beach near the Settlement, commences in the month of October, moving towards the S.W., which, as I was informed by Lieutenant Evans, is caused by a change in the prevailing direction of the currents.
Calcareous deposits are rapidly building up these terraces in various beautiful forms, the edges of many being supported by delicate columns, some of which resemble organ pipes. Different names are given to the terraces according to form or fancy, as Pulpit Terrace, Jupiter Terrace, Narrow Gauge Terrace, Minerva Terrace, etc.
This calcareous matter not only tends continually to choke its bed, but clothes the precipices over which the torrent thunders with fantastic drapery of stalactite; and, carried on the wind in foam, incrusts the forests that surround the falls with fine white dust.
It so happens that calcareous skeletons, exactly similar to the Globigerinoe of the chalk, are being formed, at the present moment, by minute living creatures, which flourish in multitudes, literally more numerous than the sands of the sea-shore, over a large extent of that part of the earth's surface which is covered by the ocean.
This spot commands a view of the islet of Cubagua, the lofty hills of Margareta, the ruins of the castle of Santiago, the Cerro de la Vela, and the calcareous chain of the Brigantine, which bounds the horizon towards the south.
It will grow in almost any soil that is capable of sustaining a vegetable, from the banks of rivulets to the top of the thin-soiled calcareous hills, where it produces herbage equal to any other plant of the kind; and all descriptions of cattle eat it, and are nourished by the food. The plant is of easy culture, as it yields seeds very abundantly, and they grow very readily.
At Cumana, for instance, before the great catastrophe of 1797, the earthquakes were felt only along the southern and calcareous coast of the gulf of Cariaco, as far as the town of that name; while in the peninsula of Araya, and at the village of Maniquarez, the ground did not share the same agitation.
It is well known that many plants appear to select certain mineral soils and avoid others, that a number of plants which prefer calcareous soils are grouped together as calcicoles, and others which shun such ground as calcifuges. Herr Hoffman has grown the specimen which has been cited by many authors as absolutely calcifugic.
If the original writing has been done with a very acid ink on a paper containing a carbonate, such as calcium carbonate, the ink, in attacking the calcareous salt, stains the paper, so that if the forger has removed the ferruginous salts this removal is denoted by the semi-transparence that water gives to the paper.
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