Climbing the path of a recent snow-slide, which had cleared a narrow path in the fifteen-foot drifts, they could smell sulphur strongly from near the South base onward. Veering around to the East, past half a dozen cinder cones, they finally reached a narrow ridge leading directly to, as yet unoccupied, the fire outlook station. Clambering over crags so steep, finally, that they could not see ahead, they came to the little square building, now tattered by the stones that had fallen through its roof, tethered to the few feet of space available by wire cables that seemed to hold it down in the teeth of the winds. Suddenly below them lay the bowl of the ancient crater, bordered by snow fields now gray with ash. That the ash had not been hot they judged from the fact that it had nowise melted the snow, but lay on its surface. From the ragged edge of the steaming basin, yellow with sulphur, rose the oppressive fumes they had been getting more and more strongly. How deep was this funnel to the interior of the earth? To their amazement it appeared to be only about 80 feet deep. That, they decided,—coupled with the fact that the ash and rocks exploded had not been hot, but cold, must be because the sides of the crater, as they gradually caved in, must have choked the neck of the crater with débris, which had been expelled when the smoke and gases had been exploded. There had been no lava flow, then!
They had retraced their steps to perhaps half a mile’s distance when of a sudden the earth beneath their feet began to heave and rumble thunderously. Ashes and rocks, some the size of flour sacks, some huge bowlders, began shooting into the air,—observers at a distance assuring them afterwards that the smoke must have risen 3,000 feet above the peak. It grew black as midnight, the smoke stung their eyes and lungs and whiffs of sulphur nearly overwhelmed them.
It was a position of deadly peril. Quick as thought, they ran, Norris dragging his companion after him, beneath the shelter of an overhanging ledge, where at least the rocks could not fall on them, and there they buried their faces in the snow and waited.
What seemed hours was later pronounced to have been but fifteen minutes, though with the roaring as of mighty winds, and the subterranean grumblings and sudden inky night, the crashing of stones and thundering of rolling bowlders, it seemed like the end of the world.
Norris’s companion had suffered a blow that dislocated his shoulder, but otherwise they emerged unhurt. They afterwards found several areas on the sides of Lassen where sulphurous gases were escaping from pools of hot mud or boiling water. They also visited a lake that had been formed at the time of the lava flow of 200 years ago, (now a matter of legend among the Pitt River Indians), this lava having formed a dam across a little valley which later filled from the melting snows. The stumps of the inundated trees could still be seen.
A geyser, said the Geological Survey man, is just like a volcano, only it expels steam and boiling water from the interior. There is a line of volcanic activity up and down the Pacific Coast, from Alaska to Central America, though Lassen is the only active peak in California, Shasta having become quiescent save for the hot spring that steams through the snow near its summit.
The North half of the range, he added, is covered with floods of glassy black lava and dotted with extinct craters, whereas the Southern half is almost solid granite, though there are plenty of volcanic rocks to be found among its wild gorges. The rocks around Lassen tell a vivid story of the chain of fire mountains that must have again and again blazed into geysers of molten rock, till the whole smoking range was quenched beneath the ice of that last glacier period, which through the ages has been sculpturing new lake and river beds, and grinding soil for the rebirth of the mighty forests.
The boys drowsed off that night to dream of fire mountains and explorations in the nether regions.
The next day they planned to bi-plane up and down the John Muir trail again and see if the Mexicans could have crossed to the Eastern side of the range. They might have made their way through some pass, traveling after nightfall and hiding by day, and once on the desert around Mono Lake they would be easy to locate. For it seemed ridiculous that they could actually make a get-away.