Shasta is a fire-mountain, an old volcano gradually accumulated and built up into the blue deep of the sky by successive eruptions of ashes and molten lava which, shot high in the air and falling in darkening showers, and flowing from chasms and craters, grew outward and upward like the trunk of a knotty, bulging tree.  Not in one grand convulsion was Shasta given birth, nor in any one special period of volcanic storm and stress, though mountains more than a thousand feet in height have been cast up like molehills in a night—­quick contributions to the wealth of the landscapes, and most emphatic statements, on the part of Nature, of the gigantic character of the power that dwells beneath the dull, dead-looking surface of the earth.  But sections cut by the glaciers, displaying some of the internal framework of Shasta, show that comparatively long periods of quiescence intervened between many distinct eruptions, during which the cooling lavas ceased to flow, and took their places as permanent additions to the bulk of the growing mountain.  Thus with alternate haste and deliberation eruption succeeded eruption, until Mount Shasta surpassed even its present sublime height.

Then followed a strange contrast.  The glacial winter came on.  The sky that so often had been darkened with storms of cinders and ashes and lighted by the glare of volcanic fires was filled with crystal snow-flowers, which, loading the cooling mountain, gave birth to glaciers that, uniting edge to edge, at length formed one grand conical glacier—­a down-crawling mantle of ice upon a fountain of smouldering fire, crushing and grinding its brown, flinty lavas, and thus degrading and remodeling the entire mountain from summit to base.  How much denudation and degradation has been effected we have no means of determining, the porous, crumbling rocks being ill adapted for the reception and preservation of glacial inscriptions.

The summit is now a mass of ruins, and all the finer striations have been effaced from the flanks by post-glacial weathering, while the irregularity of its lavas as regards susceptibility to erosion, and the disturbance caused by inter- and post-glacial eruptions, have obscured or obliterated those heavier characters of the glacial record found so clearly inscribed upon the granite pages of the high Sierra between latitude 36 degrees 30 minutes and 39 degrees.  This much, however, is plain:  that the summit of the mountain was considerably lowered, and the sides were deeply grooved and fluted while it was a center of dispersal for the glaciers of the circumjacent region.  And when at length the glacial period began to draw near its close, the ice mantle was gradually melted off around the base of the mountain, and in receding and breaking up into its present fragmentary condition the irregular heaps and rings of moraine matter were stored upon its flanks on which the forests are growing.  The glacial erosion of most of the Shasta lavas gives