from beneath through an opening nine feet in diameter, in the midst of a
pool of water six feet deep, and having an unvarying temperature of
forty-nine degrees throughout the year. This water is so perfectly clear
that not the least pebble is obscured from view, and the color scheme is
most marvelous.

[Illustration: Greer Spring. Page 88.]

Where the great spring forces its way to the surface, the water is a
deep, brilliant blue with white caps, and its falling weight keeps clear
of moss a large spot of fine, pure, white sandstone, while all the
balance appears a vivid green from the moss that thrives beneath the
moving water; and surrounding these are the handsome, foliage-decked
grey walls. The edges of the basin are thickly strewn with fallen rocks
deeply covered with moss, in which small ferns are growing, and on these
gay stepping stones we crossed to the head-wall of the cañon to find
ourselves at the open mouth of a cave from which flows a clear, shallow
stream to join the waters of the Spring in that wonderful basin. The
entrance to the cave is an arch about fifteen feet wide and twelve feet
high, with the clear, shallow stream spreading over the clean rock floor
from side to side. Here now was presented a difficulty. Truly the cave
was _not_ quite dry. The water was about ten inches deep, and my boots
in Thayer. Contrary to advice, however, my nephew had brought his, and
with a boy's kindness loaned them while he made the trip with bare feet
and rolled up trousers.

A short distance within, the cave widens and the floor of the extension
being somewhat higher, is dry, but the roof drops so low over it that
the water-course is an easier route of travel; and this soon widens
into a lake above which the ceiling rises in a broad dome less than