Personal Narrative Of Travels To The Equinoctial Regions Of America During The Years 1799-1804 - Volume 3 - By Alexander Von Humboldt And Aime Bonpland.



































































































































 -  The
blocks heaped together, which are found in Europe on the ridge of
granitic mountains (the Riesengebirge in Silesia, the - Page 570
Personal Narrative Of Travels To The Equinoctial Regions Of America During The Years 1799-1804 - Volume 3 - By Alexander Von Humboldt And Aime Bonpland. - Page 570 of 635 - First - Home

Enter page number    Previous Next

Number of Words to Display Per Page: 250 500 1000

Save Money On Flights

The Blocks Heaped Together, Which Are Found In Europe On The Ridge Of Granitic Mountains (The Riesengebirge In Silesia, The

Ochsenkopf in Franconia), are especially remarkable in the north-west part of the Sierra Parime, between Caycara, the Encaramada and

Uruana, in the cataracts of the Maypures and at the mouth of the Rio Vichada. It is doubtful whether these masses, which are of cylindrical form, parallelopipedons rounded on the edge, or balls of 40 to 50 feet in diameter, are the effect of a slow decomposition, or of a violent and instantaneous upheaving. The granite of the south-eastern part of Sierra Parime sometimes passes to pegmatite,* composed of laminary felspar, enclosed in curved masses of crystalline quartz. (* Schrift-granit. It is a simple modification of the composition and texture of granite, and not a subordinate layer. It must not be confounded with the real pegmatite, generally destitute of mica, or with the geographic stones (piedras mapajas) of the Orinoco, which contain streaks of dark green mica irregularly disposed.) I saw gneiss only in subordinate layers;* (* The magnetic sands of the rivers that furrow the granitic chain of the Encaramada seem to denote the proximity of amphibolic or chloritic slate (hornblende or chloritschiefer), either in layers in the granite, or superposed on that rock.); but, between Javita, San Carlos del Rio Negro, and the Peak of Duida, the granite is traversed by numerous veins of different ages, abounding with rock-crystal, black tourmalin and pyrites. It appears that these open veins become more common on the east of the Peak of Duida, in the Sierra Pacaraina, especially between Xurumu and Rupunuri (tributaries of the Rio Branco and the Essequibo), where Hortsmann discovered, instead of diamonds* and emeralds, a mine (four) of rock-crystal.

Enter page number   Previous Next
Page 570 of 635
Words from 156665 to 156958 of 174507


Previous 570 571 572 573 574 575 576 577 578 579 Next

More links: First 10 20 30 40 50 60 70 80 90 100
 110 120 130 140 150 160 170 180 190 200
 210 220 230 240 250 260 270 280 290 300
 310 320 330 340 350 360 370 380 390 400
 410 420 430 440 450 460 470 480 490 500
 510 520 530 540 550 560 570 580 590 600
 610 620 630 Last

Display Words Per Page: 250 500 1000

 
Africa (29)
Asia (27)
Europe (59)
North America (58)
Oceania (24)
South America (8)
 

List of Travel Books RSS Feeds

Africa Travel Books RSS Feed

Asia Travel Books RSS Feed

Europe Travel Books RSS Feed

North America Travel Books RSS Feed

Oceania Travel Books RSS Feed

South America Travel Books RSS Feed

Copyright © 2005 - 2012 Travel Guides