Page:Popular Science Monthly Volume 86.djvu/301

Rh The limit of the heavy fall of ash not wind-borne was quite definitely marked on June 26 and was probably within a circle of less than a mile. It had not, however, a uniform border. In making the ascent on that day, instead of the regular trail a more easterly route was taken, leading up the southeasterly ridge directly to the fire lookout station. This ridge, which lies in the general direction of the longitudinal opening of the crater itself, was found to be much more heavily covered with ash than the regular trail. While the main outbursts were usually directly upward in the eruption described, irregular streaks of ash such as the one just noted prove that there were minor outshoots of volcanic dust in various directions. Exaggerated reports of the distance to which stones were thrown seem to have been based upon their being



found on the outer slopes of the old crater resting upon the surface of the snow, but the fact that stones are constantly being dislodged from the cliffs by ordinary weathering processes and are rolling down the mountain side shows the need of additional criteria. To avoid mistaking such stones for those thrown through the air by eruption, careful search was made on level patches of the old snow so located that it was impossible for stones to roll down upon them. Wherever such level surfaces were found there was no evidence at that time of ejected stones falling at a much greater distance than to the lookout house, certainly at no point over a half mile from the crater.

In climbing Lassen Peak from the southeast up to the crag upon which the Forest Service station is built the slope is so steep and rugged that the final ascent is made without any glimpse of what is ahead. As the last rocks are scaled and one stands on the wind-swept crag by the fragments of the little frame building once bound down to the rocks by