overgrown by shrubbery. The northern border constitutes a line of
vertical cliffs of yellowish and white pumice, projecting and
re-entering like decorations of a stage,--now perpendicular and smooth
for some distance, now sweeping back in the shape of an arched segment.
These cliffs vary in height, although nowhere are they less than two
hundred feet. Their tops rise in huge pillars, in crags and pinnacles.
Brushwood and pine timber crown the mesa of which these fantastic
projections are but the shaggy border.

Through the vale itself rustles the clear and cool brook to which the
name of Rito de los Frijoles is applied. It meanders on, hugging the
southern slope, partly through open spaces, partly through groves of
timber, and again past tall stately pine-trees standing isolated in the
valley willows, cherry-trees, cottonwoods, and elders form small
thickets along its banks. The Rito is a permanent streamlet
notwithstanding its small size. Its water freezes in winter, but it
never dries up completely during the summer months.

Bunches of tall grass, low shrubbery, and cactus grow in the open spaces
between rocky débris fallen from above. They also cover in part low
mounds of rubbish, and ruins of a large pentagonal building erected
formerly at the foot of a slope leading to the cliffs. In the cliffs
themselves, for a distance of about two miles, numerous caves dug out by
the hand of man are visible. Some of these are yet perfect; others have
wholly crumbled away except the rear wall. From a distance the
port-holes and indentations appear like so many pigeons' nests in the
naked rock. Together with the cavities formed by amygdaloid chambers and
crevices caused by erosion, they give the cliffs the appearance of a
huge, irregular honeycomb.