COHNEXIOS OF TOLCANIC ACTION. 
403 
trachytes, at a distance of eighteen or twen^-^e leagues 
from the present coast of the Pacific Ocean.* Permanent 
communiLions. or at least communications requently 
renewed between the atmospliere and the interior ot the 
globe, have been preserved only along that immense crevice 
on which the Cordilleras have been upheaved; but sub- 
terranean volcanic forces are not 
America, shaking the soil ot the littoral Cordillera ot 
Venezuela, and of the Parime group. In desmbing the 
phenomena which accompanied the great ^ 
Lracas,t on the 26th March, 1812, 1 mentioned the detona- 
tions hoard at difierent periods, in the mountains (altogether 
granitic) of the Orinoco. The elastic forces which agitate 
thrSoind, the stUl-buriiing volcanos, the hot sulphurous 
sprigs, sometimes containing fluoric md, the presence of 
asnhaltum and naphtha in primitive strata, all point to the 
interior of our planet, the high temperature of which is per- 
ceived even in mines of little depth, and which, fiom the 
times of lleraclitus of Ephesus, and Anaxagoras of Clazo- 
men® to the Plutonic theory ot modern days, has been 
considered as the seat of all great 
The sketch I have just traced contains all the foimatioiis 
knoum in that part of Europe lyhich has served as the 
tvne of positive geology. It is the fiuit ot sixtee i 
months’ labour, often interrupted by other occupations. 
Porinatioiis of quartzose porphyry, pyroxeiuc porphyi) 
Ld trachyte, of ^auwacke, muschelkalk, and quadersaud- 
* I believe the — dt 
l“;tated in another place the influence of that great catastrophe on 
order had nothing in common with it. Aiclilnsliop i rar lo 
after this singular correspondence 2 D 2 
