ANDES. 
  
that is impracticable, sometimes surmount them 
by bridges, and sometimes avoid them by means 
of a path cut along the shoulder of the overhanging 
height. 
With respect to the mountain-torrents, Herndon, 
after leaving Antarangra behind him, was enabled 
to avail himself chiefly of this resource. ¢As far as 
the traveller,” says he, ¢is concerned, there are not, 
on the route we have travelled, two ranges of the 
A.—that is, he has not to ascend and descend one 
range, and then ascend and descend another. From 
the time that he crosses at Antarangra, his progress 
is downward, till he reaches the plain. Really, 
however, there are two ranges. The streams from 
the first or western range have broken their way 
through the second, making deep gorges, at the 
bottom of which the road generally runs, and leaves 
the peaks of the second range thousands of feet 
above the traveller’s head.’ 
In addition to the essential perils of such a 
course, Herndon encountered, on one occasion, an 
incidental danger, which he thus describes—the 
scene being a mnarrow path on the shoulder 
of an almost precipitous hill: ¢Mr Gibbon was 
riding ahead. Just as he was about to turn a 
sharp bend, the head of a bull peered round it on 
the descent. When the bull came in full view, he 
stopped ; and we could see the heads of other cattle 
clustering over his quarters, and hear the shouts of 
the cattle-drivers, far behind, urging on their herd. 
I happened to be abreast of a slight natural excava- 
tion ; and dismounting, I put my shoulder against 
my mule’s flank, and pressed her into this friendly 
retreat ; bub I saw no escape for Gibbon. The bull, 
with lowered crest and savage look, came slowly on, 
and actually got his head between the perpendicular 
wall and the neck of Gibbon’s mule. But his saga- 
cious beast, pressing her haunches hard against the 
rock, gathered her feet close under her, and turned 
as on a pivot. This placed the bull on the outside ; 
and he rushed by at the gallop, followed in single 
file by the rest of the herd. 
In the bridging of the mountain-torrents, a good 
deal of rude ingenuity is displayed. Sometimes 
chains are suspended from side to side; and some- 
times a rough flooring is laid between projecting 
beams from either bank, which have previously been 
fixed as solidly as possible. Nature also has done 
something in this respect to help man, having thrown 
two bridges of her own over a fearful chasm at 
Icononzo. The torrent, which they span, falls down 
a beautiful cataract into a murky crevice—the noisy 
haunt of nocturnal birds. At a height of 400 feet 
above the foaming waters, the two bridges hang in 
mid-air, both of them, apparently, though in differ- 
ent ways, the work of an earthquake. The upper 
one is merely a fragment of the original sandstone, 
which must have resisted the shock that formed the 
rent; while the lower, probably the most singular 
arch in the world, consists of three detached rocks, 
so adjusted as to support each other. 
The loftiest pinnacles of the A., when viewed 
from the table-lands, and, still more, when seen 
from the crests of the passes, lose, to the eye of 
the beholder, much of their real altitude. Under 
such circumstances, not a single mountain presents 
the actual dimensions of Mont Blane, as over- 
hanging the Vale of Chamouni. It is only from 
a distance—best of all, perhaps, from a good 
offing in the Pacific—that the A. appear in all 
their gigantic proportions. Standing thus on their 
pedestal, the most rugged and colossal in nature, 
they almost realise to the spectator the highest 
Pyrenees piled on the highest Alps; while, to 
enhance the grandeur of the scene, the igneous 
action, which has heaved the chain into existence, 
240 
is here and there adding to its stature a pillar of 
smoke and flame. 
The geology of the A. is as yet very little 
known. It is more than half a century since Hum- 
boldt travelled through these mountains, and to 
him we are even now chiefly indebted for our 
knowledge regarding them. At that time, geology 
was in 1ts infancy—its language had not been 
formed, its classification, at least as it now exists, 
was unknown, and its facts were mixed with absurd 
and now long-exploded theories ; it could, in fact, 
scarcely be called a science. It is fortunate that as 
regards the materials constituting the great mass of 
the A. range—the igneous rocks which form its 
back-bone, and the metamorphic rocks which form 
its great bulk—our knowledge was almost as exten- 
sive and explicit 50 years ago as it is now, and 
therefore, in respect to them, Humboldt’s observa- 
tions are as good as if made but yesterday. Not so 
as regards the more recent sedimentary formations, 
The value of fossils was not then known, and the 
vaguest ideas prevailed as to the chronological 
  
  
order of the stratified rocks. Hence descriptions 
written at that time are almost valueless to modern 
science. A few scattered notes may be gleaned from 
the small number of intelligent travellers who have 
recently visited these mountains; and to them we 
are obliged for any of the facts we are able to give 
regarding the deposits referred +o. 
The elevation of the A. took place at an epoch 
anterior to the formation of the Rocky Mountains 
of North America, which are geographically a con- 
tinuation of them. They are composed, to a very 
  
  
large extent, of -stratified metamorphic rocks. It 
is remarkable that granite occurs in them not as an 
unstratified plutonic rock, but only intercalated 
with the other members of the stratified azoic series. 
The true igneous rocks belong either to the trappean 
or volcanic divisions. The grand ridge is everywhere 
covered with one or other of the varieties of trap 
(greenstone, clinkstone, basalt, or porphyry). Thes 
are often broken into columns, and appear at a dis- 
tance like ruined castles, producing a very striking 
effect. 
Bursting through the trap-rocks, there are a num- 
ber of volcanoes covering their summits with more 
recent igneous rocks. Among the mountains spe- 
cified above as to altitude, Yanteles, Corcobado, 
Minchinadom, Antuco, Gualtieri, Arequipa, Cotopaxi, 
Antesana, and Pichincha belong to this class. Fifty- 
one volcanoes have been described as existing 
throughout the whole range. The mountains of 
Ecuador are so extensively and continuously of 
volcanic origin, that they have been regarded as 
different safety-valves of one and the same burnin g 
vault. It is generally maintained that there is a rela. 
tion between the height of a volcano and its activity 
and the frequency of its eruptions. Thus, Stromboli 
(2957 feet) has continued in a state of activity since 
the earliest ages, serving the purpose of a light-house 
to the navigators of the Tyrrhenian Sea; while 
Cotopaxi (18,887 feet) and Tunguragua (16,579 feet) 
have been active only once in a hundred years. 
Many of these 51 volcanoes have consequently not 
yet been observed by Europeans in an active state. 
In the Quito district there are 10 active, and 7 of 
doubtful activity ; in Peru and Bolivia, the numbers 
are 9 and 3; in Chili, 17 and 5 : making in all 36 
active, and 15 about which there is some uncer- 
tainty as to their activity., Another characteristic 
of these volcanoes, resulting from their gigantic alti- 
tude, is that few of them emit streams of lava, 
Thus Antisana is probably the only one in the Quito 
range that has ejected lava. The force, however, 
which is repressed apparently by the immense super- 
  
  
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