XY 
PINNACLES OF SNOW 
347 
Tupungato, the whole clothed with unbroken snow, in the 
midst of which there was a blue patch, no doubt a glacier ;— 
a circumstance of rare occurrence in these mountains. Now 
commenced a heavy and long climb, similar to that up the 
Peuquenes. Bold conical hills of red granite rose on each 
hand ; in the valleys there were several broad fields of perpetual 
snow. These frozen masses, during the process of thawing, 
had in some parts been converted into pinnacles or columns, 1 
which, as they were high and close together, made it difficult 
for the cargo mules to pass. On one of these columns of ice 
a frozen horse was sticking as on a pedestal, but with its hind 
legs straight up in the air. The animal, I suppose, must have 
fallen with its head downward into a hole, when the snow was 
continuous, and afterwards the surrounding parts must have 
been removed by the thaw. 
When nearly on the crest of the Portillo, we were enveloped 
in a falling cloud of minute frozen spicula. This was very un¬ 
fortunate, as it continued the whole day, and quite intercepted 
our view. The pass takes its name of Portillo from a narrow 
cleft or doorway on the highest ridge, through which the road 
passes. From this point, on a clear day, those vast plains 
which uninterruptedly extend to the Atlantic Ocean can be 
seen. We descended to the upper limit of vegetation, and 
found good quarters for the night under the shelter of some 
large fragments of rock. We met here some passengers, who 
made anxious inquiries about the state of the road. Shortly 
after it was dark the clouds suddenly cleared away, and the 
effect was quite magical. The great mountains, bright with 
the full moon, seemed impending over us on all sides, as over 
a deep crevice : one morning, very early, I witnessed the same 
striking effect. As soon as the clouds were dispersed it froze 
severely ; but as there was no wind, we slept very comfortably. 
The increased brilliancy of the moon and stars at this eleva¬ 
tion, owing to the perfect transparency of the atmosphere, was 
1 This structure in frozen snow was long since observed by Scoresby in the 
icebergs near Spitzbergen, and lately, with more care, by Colonel Jackson [Journ. of 
Geograph. Soc. vol. v. p. 12) on the Neva. Mr. Lyell ( Principles , vol. iv. p. 360) 
has compared the fissures, by which the columnar structure seems to be determined, 
to the joints that traverse nearly all rocks, but which are best seen in the non- 
stratified masses. I may observe that in the case of the frozen snow the columnar 
structure must be owing to a “ metamorphic ” action, and not to a process during 
deposition. 
