his ridge is separated
from the higher mass of hills within by a valley one to three miles in
breadth, which is known as the Red Valley, from its brick-red soil, or
the 'race course,' which name was given it by the Indians because of its
open and smooth character, affording easy and rapid passage around the
Hills. The junction of the outer base of the Hills with the surrounding
table lands has an altitude of three thousand, five hundred to four
thousand feet. Within this Red Valley one gradually ascends the outer
slope of the Hills and soon enters, at an altitude of four thousand five
hundred or five thousand feet, the woody portion of the region. This
outer slope varies greatly in width and is underlaid by older
sedimentary rocks, cut in almost every direction by narrow deep canons.
This feature covers nearly the whole of the western half of the Hills
proper, where erosion has been less active on account of its distance
from the main channels of drainage. Usually, from the broken interior
edge of this slope or sedimentary plateau one descends a bluff or
escarpment, and enters the central area of slates, granite, and
quartzites, which is carved into high ridges and sharp peaks cut by many
narrow and deep valleys and ravines and generally thickly timbered with
the common pine of the Rocky Mountains. Toward the south, about Harney
Peak, the surface is peculiarly rugged and difficult to traverse. Toward
the north, also, about Terry and Custer peaks, a smaller rugged surface
appears; but in the central area between and extending west of the
Harney range is a region which is characterized by open and level parks
much lower than the surrounding peaks and ridges."

The Archaean rocks which form the core of the Hills mark the center of
the various uplifts which have attended their formation and controlled
their history. The coarse granite of Harney Peak indicating that, as the
central point of the earliest upheaval, and the three porphyries known
as rhyolite, trachyte, and phonolite, showing the uplifts of later
periods to have had their centers a little more to the north, but the
entire area is said to be only about sixty miles long and twenty-five
miles in width. It is exceptionally rough and mountainous, and
consequently has great charms for the lover of fine scenery. Erosion has
only partially denuded the peaks of the sedimentary rocks through which
they were thrust up, or by which they were overlaid during the earlier
part