ingered into the afternoon and then
drove to the Mammoth Spring, in Arkansas, a short distance south of the
Missouri state line, where the Cave River, just visited, comes to the
surface in a bounding spring of great force. The distance being little
less than nine miles.

The basin filled by the Spring might be called a lake, as its size of
two hundred by three hundred feet gives it that appearance, and the
color is a remarkable deep blue. The volume of water is so nearly
uniform that the height seldom varies more than two or three inches,
but three years ago a storm of unusual violence carried out most of the
native fish, and in restocking from Government supplies, the clear, cold
water suggested an experiment with mountain trout which are found to be
doing well.

Where Mammoth Spring flows out its power is utilized by a flour mill on
one bank and a cotton mill on the other, and the water flowing on forms
Spring River, well known for the charm of its beautiful scenery.

This Spring is described by Dr. David Dale Owen in his First Report of a
Geological Reconnoissance of the northern counties of Arkansas, 1857 and
1858, pp. 60-61.

CHAPTER VIII.

THE BLACK HILLS AND BAD LANDS.

In order to thoroughly appreciate and enjoy the wonderful caves of South
Dakota, which are found within the limits of the Black Hills, it is
necessary to have some knowledge of the geological character and history
of that peculiar region.

Prof. J.E. Todd, State Geologist, in his "Preliminary Report on the
Geology of South Dakota," gives an interesting "Historical Sketch of
Explorations" in his state, beginning with the expedition of Captains
Lewis and Clark to the upper Missouri regions in 1804-6 to explore that
portion of the recent Louisiana Purchase for the government and notify
the Indians of the transfer; and including all other important
expeditions since that time down to his own official tour of the Black
Hills and Bad Lands in 1894. His own descriptions are so concise and
graphic as to invite quotation. Of the Hills he says:

"The Black Hills have an area of five-thousand square miles of a rudely
elliptical form with its major axis, approximately, north-northwest.
Most of this area lies within our state. The true limit of the Hills is
quite distinctly marked by a sharp ridge of sandstone, three hundred to
six hundred feet in relative height, which becomes broader and more
plateau-like towards the north and south ends. T