The Works of Charles Darwin: v. 9: Geological Observations on South America (1846) (with the Critical Introduction by J.W. Judd, 1890) by Paul H Barrett

Author:Paul H Barrett [Barrett, Paul H]
Language: eng
Format: epub
Tags: History, General, Science
ISBN: 9781315477329
Google: 1h-3DAAAQBAJ
Publisher: Routledge
Published: 2016-07-22T16:18:09+00:00

Notes

1 Voyage, Part. Géolog., pp. 57 to 65.

2 Monatsberichten der König. Akad. zu Berlin, April, 1845.

3 At this spot, for a space of three quarters of a mile along the north side of the river, and for a width of half a mile, there has been a great slip, which has formed hills between 60 and 70 feet in height, and has tilted the strata into highly inclined and even vertical positions. The strata generally dipped at an angle of 45° towards the cliff from which they had slided. I have observed in slips, both on a small and large scale, that this inward dip is very general. Is it due to the hydrostatic pressure of water percolating with difficulty through the strata, acting with greater force at the base of the mass than against the upper part?

4 I found at both places, but not in situ, quantities of coniferous and ordinary dicotyledonous silicified wood, which was examined for me by Mr R. Brown.

5 Memoire spour Servir, etc., pp. 178 and 217.

6 Described in the Geological Transactions, vol. vi, p. 415.

7 Botany of the Antarctic Voyage, p. 212.

8 In a cliff of the hardest fragmentary mass, I found several tortuous, vertical veins, varying in thickness from a few tenths of an inch to one inch and a half, of a substance which I have not seen described. It is glossy, and of a brown colour; it is thinly laminated, with the laminae transparent and elastic; it is a little harder than calcareous spar; it is infusible under the blowpipe, sometimes decrepetates, gives out water, curls up, blackens and becomes magnetic. Borax easily dissolves a considerable quantity of it, and gives a glass tinged with green. I have no idea what its true nature is. On first seeing it, I mistook it for lignite!

9 The frequent tendency in iron to form hollow concretions or shells containing incoherent matter is singular: D’Aubuisson (Traité de Géogn., tom. i, p. 318) remarks on this circumstance.

10 Zoology of Captain Beechey’s Voyage, p. 163.

11 I was guided to this locality by the Report on M. Gay’s geological researches, in the Annales des Scienc. Nat. (1st series), tom. 28.

12 M. d’Orbigny states that the genus Natica is not found on the coast of Chile; but Mr Cuming found it at Valparaiso. Scalaria was found at Valparaiso, Arca, at Iquique, in lat. 20°, by Mr Cuming; Arca, also, was found by Captain King, at Juan Fernandez, in lat. 33° 30′.

13 It may be worth while to mention, that the shells living at the present day on this eastern side of S. America, in lat. 40°, have perhaps a more tropical character than those in corresponding latitudes on the shores of Europe: for at Bahia Blanca and S. Blas, there are two fine species of Voluta, and four of Oliva.

14 Professor H. D. Rogers, in his excellent address to the Association of American Geologists (Silliman’s Journal, vol. 47, p. 277), makes the following remark: ‘I question if we are

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.