of the mountain, show that it has been considerably lowered and wasted
by ice; how much we have no sure means of knowing. Just below the
extreme summit hot sulphurous gases and vapor issue from irregular
fissures, mixed with spray derived from melting snow, the last feeble
expression of the mighty force that built the mountain. Not in one great
convulsion was Shasta given birth. The crags of the summit and the
sections exposed by the glaciers down the sides display enough of its
internal framework to prove that comparatively long periods of
quiescence intervened between many distinct eruptions, during which the
cooling lavas ceased to flow, and became permanent additions to the bulk
of the growing mountain. With alternate haste and deliberation eruption
succeeded eruption till the old volcano surpassed even its present
sublime height.

[Illustration: MOUNT SHASTA, LOOKING SOUTHWEST.]

Standing on the icy top of this, the grandest of all the fire-mountains
of the Sierra, we can hardly fail to look forward to its next eruption.
Gardens, vineyards, homes have been planted confidingly on the flanks of
volcanoes which, after remaining steadfast for ages, have suddenly
blazed into violent action, and poured forth overwhelming floods of
fire. It is known that more than a thousand years of cool calm have
intervened between violent eruptions. Like gigantic geysers spouting
molten rock instead of water, volcanoes work and rest, and we have no
sure means of knowing whether they are dead when still, or only
sleeping.

Along the western base of the range a telling series of sedimentary
rocks containing the early history of the Sierra are now being studied.
But leaving for the present these first chapters, we see that only a