231 
in the higher Alps. On advancing from Po- 
payan toward the souths we see on the arid ele- 
vated plain of the province of Los Pastos the 
three small chains of the Andes lost in one 
group, which stretches far beyond the equa- 
tor. 
This group, in the kingdom of Quito, pre^ 
sents an extraordinary appearance from the 
river of Chota, which meanders amid moun- 
tains of basaltic rock to the Paramo of Assuav, 
on which are seen , some remarkable remains of 
Peruvian architecture. The most elevated sum- 
mits are arranged in two lines, which form as 
it were a double ridge to the Cordilleras. These 
colossal summits, covered with perpetual ice, 
served for signals in the operations of the French 
academicians at the time of the measurement 
of the equinoxial degree. Their symmetrical 
disposition, in two lines directed from north to 
south, has led Bouguer to consider them as 
two chains of mountains, separated by a longi- 
tudinal valley : but what this celebrated astro- 
nomer calls the bottom of a valley is the summit 
of the Andes itself ; it is an elevated plain, the 
absolute height of which is from two thousand 
seven hundred to two thousand nine hundred 
metres. We must not confound a double 
ridge with a real ramification of the Cordil- 
leras. 
The plain covered with pumice stone, that 
