466 



with the heaving-up of the whole chain. It 

 maybe said that the phenomenon of the steeps or 

 narrow declivities of Sarenthal and of the valley 

 of Eysack in the Tyrol, is repeated at every step, 

 and on a greater scale in the Cordilleras of 

 equinoxial America. We seem to recognize 

 those longitudinal sinkings, those (i rocky 

 vaults/' which , to use the expression of a great 

 geologist " are broken when extended over a 

 great space, and leave deep and almost perpen- 

 dicular rents." 



If, to complete the sketch of the structure 

 of the Andes, from the Land of Fire to the 

 northern Polar Sea, we pass the limits of South 

 America, we see the western Cordillera of New 

 Grenada, after a great depression between the 

 mouth of the Atrato and the gulph of Cupica, 

 again rise in the isthmus of Panama to 80 or 

 100 toises high-f*, augmenting towards the west, 

 in the Cordilleras of Veragua and Salamanca %, 



* Leopold de Buck, Tableau du Tyrol meridional, 1823, 

 p. 8. 



f See above. Vol. vi, p. 254, 255. 

 % If what navigators affirm be true, that the mountains at 

 the N. W. extremity of the republic of Columbia, and known 

 by the names of Silla de Veragua, and Castillo del Choco 

 (in the meridian of the Boca del Toro, and la Laguna Chi- 

 riqui), are visible at 36 leagues distance (Pardy, Columbian 

 Navigator, p. 134), the elevation of their summits must be 

 nearly 1400 toises, and would differ little from that of the 

 Silla de Caraccas. 



