436

1835 Appendix p 54. — Chili

conjointly have determined "the disposition of the great slopes, which compose the polyedrical surface of the plains" Vol V P 1 p 450¹ Phenomena —which Humboldt has so admirably explained in his discussion on the intertrenchings of the Orinoco & Amazons. —

He states, that the basin of the former seems primarily confounded with that of the latter.

The junction of the basin takes place, as the analogy from Deltas would suggest, where the the ground is exceedingly horizontal. This happens in the space included between the long slope from the Cordilleras of New Grenada & the shorter counterslope from the Sierra Parime. —

Does not this remarkable equality in the configuration of the ground arise from the long & tranquil residence of an ocean? Where by the gradual rise of the land, the Sierra Parime first existed as a large island, did not its degradation from the counterslope & subsequently. the level region, where the waters of the two great rivers could intermingle? — It is only by such considerations, that it is possible to explain "the analogous & very remarkable example, which Hungary

¹ Humboldt 1819-1829, vol. 5, part 1, pp. 453-4: "We should seek in vain on these points of counterflexure, so important to geography, any mountains or hills, that prevent the great river from continuing it's original course. None exist at the mouth of the Guaviare; and the little hill of Cabruta, near the confluence of the Apure, has certainly had no influence on the direction of the Oroonoko. These variations of direction are the effect of more general causes; they result from the disposition of the great slopes, which compose the polyedrical surface of the plains. The chains of mountains do not rise like walls on horizontal plains; their masses, more or less prismatic, are always supported by table-lands, and these are lengthened out into slopes".

436 verso

The foregoing pages with mere propriety ought solely to apply to formation of land in S. America. This last sheet generally. —

437

1835 Appendix P. 54

furnishes of rivers, which rising to the S of a chain of mountains belong to the hydraulic system of its northern declivity."¹ — With respect to the great influence, which my examination of S. America, has induced me to grant to a retiring ocean, in determining the configuration of the land: it must be remembered, the more remote the epoch of the two first causes, the less will the evidence the of their power grow. —

The long possession by a river of its valley, will make its claims of being the sole labourer in the work of excavation more plausible. —

From this cause the converse of this happening in Chili I have ventured to describe minutely, what I there observed in Chili & still more boldly I have ventured to generalize the results. —

¹Humboldt 1819-1829, vol. 5, part 1, p. 459.

437 verso

page 1. red note Book ¹

A chain of islands formed Sumatra like Chile must once have been. —

¹ Red notebook, p. 1 (excised and not located). There are notes on Marsden 1811 on Sumatra.