And neighbouring lines of elevation, except on this
view of the rock of the axis having been repeatedly injected,
after intervals sufficiently long to allow the upper parts or
wedges to cool and become solid; - for if the strata had been
thrown into their present highly inclined, vertical, and even
inverted positions, by a single blow, the very bowels of the
earth would have gushed out; and instead of beholding abrupt
mountain-axes of rock solidified under great pressure, deluges
of lava would have flowed out at innumerable points on every
line of elevation. [2]
[1] M. Arago in L'Institut, 1839, p. 337. See also Miers's
Chile, vol. i. p. 392; also Lyell's Principles of Geology,
chap. xv., book ii.
[2] For a full account of the volcanic phenomena which
accompanied the earthquake of the 20th, and for the conclusions
deducible from them, I must refer to Volume V. of the Geological
Transactions.
CHAPTER XV
PASSAGE OF THE CORDILLERA
Valparaiso - Portillo Pass - Sagacity of Mules - Mountain-
torrents - Mines, how discovered - Proofs of the gradual
Elevation of the Cordillera - Effect of Snow on Rocks -
Geological Structure of the two main Ranges, their distinct
Origin and Upheaval - Great Subsidence - Red Snow -
Winds - Pinnacles of Snow - Dry and clear Atmosphere -
Electricity - Pampas - Zoology of the opposite Side of
the Andes - Locusts - Great Bugs - Mendoza - Uspallata
Pass - Silicified Trees buried as they grew - Incas Bridge -
Badness of the Passes exaggerated - Cumbre - Casuchas -
Valparaiso.
