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.