404 
GEOLOGY APPLIEB TO 
stein, wliicli are frequent towards the west, have not yet 
been seen in Venezuela; but it maybe also observed that 
in the system of secondary rocks of the old continent, 
muschelkalk and qiiadersandstein are not always clearly 
developed, and are often, by the frequency ot their marls, 
confounded witli tlie lower layers of Jura limestone. 
The inusclielkalk is almost a lias with encrinites; and 
quadersandstcin (for there are doubtless many above the 
lias or limestone with gryphites) seems to me to represent 
the arenaceous layers of the lower shelves of Jura lime- 
stone. 
I hpe thought it right to give at some length this 
geologic description of South America, not only on 
account of the novel interest which the study of the forma- 
tions in the equinoctial regions is calculated to excite, but 
also on account of the honoLirable efforts which have 
recently been made in Europe to verify and extend the 
working of the mines in the Cordilleras of Columbia, 
Mexico, Chile, and Buenos Ayres. Arnst sums of money 
have been invested for the attainment of this useful end. 
In ])roportion as public confidence has enlarged and con- 
solidated those enterprises, from which both continents may 
derive solid advantage, it becomes the duty of persons 
who have acquired a local knowledge of these countries to 
publish information calculated to create a just apprecia- 
tion of the relative wealth and i}osition of the mines in 
different parts of Spanish America. The success of a 
company for the working of mines, and that of works 
undertaken by the order of free gn\ ei'nments, is far from 
depending solely on the improvement of the machines em- 
ployed for draining off the water, and extracting the 
mineral, on the regular and economical distribution of the 
subterraneous works, or the improvements in preparation, 
amalgamation, and melting; success depends also on a 
thorough knowledge of the different superposed strata 
The jmactice of the science of mining is closely luiked with 
the ])rogres3 of geology; and it would be easy to prove 
that many millions of piastres have been rashly expended 
in South America, from complete ignorance of the nature of 
the formations, and the position of the rocks, in directing 
