he walls of mountain which enclose the
valley here rise almost perpendicularly, and afford nestling-places for
small, richly-plumed parrots (_Conurus rupicola_, Tsch.). I was much
surprised to see these birds inhabiting the barren rocks, as the parrot
always dwells in woody regions, and is found in other places only when
on its passage. I know no other species of this family, save the one I
have just mentioned, which permanently nestles on mountains.

Three leagues beyond San Pedro lies the village of Cocachacra. It is a
small and poor place, but is picturesquely situated, and enjoys a fine
climate. Its name, signifying _coca-field_, or _plantation_, denotes
that coca must formerly have been cultivated here. At present that
plant is not grown in any part near the coast, as it requires a damp and
very warm climate. Cocachacra is 5386 feet above the level of the sea.
Maclean fixes the altitude of San Pedro Mama, Santa Olaya, and
Cocachacra, at 5331 feet. Supposing this calculation to be correct with
respect to the latter village, it cannot also apply to San Pedro Mama
and Santa Olaya, which lie much lower. At the two last-mentioned places
I made no barometrical observations.

On the Pasco road the hamlet of Llanga is situated, at twelve leagues
from Lima. On the other road Cocachacra is the same distance from the
capital; but Cocachacra is about 2400 feet higher than Llanga. Between
Cavallero and Llanga there is an interesting geological phenomenon,
which I will here describe.

At the distance of two leagues from Lima the road takes a turn. At first
it runs direct north, or north-north-west; suddenly it turns to
north-north-east, and advances along the bank of the river Chillon as
far as Cavallero. From thence, with slight deviations, it continues in
the same course to Llanga, but at a considerable distance from the
river, as the latter takes a wide sweep northward. From Cavallero the
road runs for the space of three leagues, still ascending, through a
barren district, along the dry bed of a river, called the Rio Seco. The
last half-league of the way is very steep, and leads to the ridge of a
chain of hillocks running diagonally across the valley. The ground is
strewed with fragments of porphyry and other kinds of rock, like the bed
of the Rimac. On reaching the ridge of the line of hillocks, the
traveller beholds on the other side a hollow basin, like the dry bed of
a lake: a furrow, extending lengthwise through this h