f the first magnitude--which reaches an elevation, according
to Wheeler, of 12,562 feet above the ocean. It has long been extinct,
and its summit and flanks are covered with snow-fields and glaciers.
Other parts of Arizona are overspread by sheets of basaltic lava,
through which old "necks" of eruption, formed of more solid lava than
the sheets, rise occasionally above the surface, and are prominent
features in the landscape.

Further to the eastward in New Mexico, and near the margin of the
volcanic region, is another volcanic mountain little less lofty than San
Francisco, called Mount Taylor, which, according to Dutton, rises to an
elevation of 11,390 feet above the ocean, and 8200 feet above the
general level of the surrounding plateau of lava. This mountain forms
the culminating point of a wide volcanic tract, over which are
distributed numberless vents of eruption. Scores of such
vents--generally cinder-cones--are visible in every part of the plateau,
and always in a more or less dilapidated condition.[3] Mount Taylor is a
volcano, with a central pipe terminating in a large crater, the wall of
which was broken down on the east side in the later stage of its
history.

[Illustration: Fig. 25.--Mount Shasta (14,511 feet), a snow-clad
volcanic cone in California, with Mount Shastina, a secondary crater, on
the right; the valley between is filled with glacier-ice.--(After
Dutton).]

(_d._) _California._--Proceeding westwards into California, we are
again confronted with volcanic phenomena on a stupendous scale. The
coast range of mountains, which branches off from the Sierra Nevada at
Mount Pinos, on the south, is terminated near the northern extremity of
the State by a very lofty mountain of volcanic origin, called Mount
Shasta, which attains an elevation of 14,511 feet (see Fig. 25). This
mountain was first ascended by Clarence King in 1870,[4] and although
forming, as it were, a portion of the Pacific Coast Range, it really
rises from the plain in solitary grandeur, its summit covered by snow,
and originating several fine glaciers.

The summit of Mount Shasta is a nearly perfect cone, but from its
north-west side there juts out a large crater-cone just below the
snow-line, between which and the main mass of the mountain there exists
a deep depression filled with glacier ice. This secondary crater-cone
has been named Mount Shastina, and round its inner side the stream of
glacier ice winds itself, sometimes surmou