Page:Popular Science Monthly Volume 86.djvu/309

Rh of being gradually liberated during the six months, been freed during a few minutes, the results would undoubtedly have been comparable to those at Bandai-San. The point, however, is that the difference is qualitative merely and that the nature and magnitude of the eruptions of Lassen Peak fully justify classing them as volcanic.

A study of the tabular summary of the eruptions gives little upon which to base an opinion as to whether the future will bring a fresh lava flow or whether there is being formed a new solfataric basin. The longest period of quiescence was from July 18 to August 10, twenty-three days. The eruptions in November, so far as observations have been made, do not differ materially from those in June. The fact that Soupan Hot Springs, Morgan Hot Springs and those in Hot Springs Valley are situated in valleys at so much lower levels than the new crater, and are apparently unconnected with Lassen, suggests the idea that the recent activity was due to a column of lava working its way upward along the core of the main peak and that this lava may yet issue as a surface flow. It is confessed, however, that the idea is based more on hope than on any scientific data. A visit in July to Bumpass’ Hell showed a crater-like depression filled with hot springs, boiling mud pots, and solfataras, yet it is situated on the crest of a high ridge, some two or three thousand feet above Hot Springs Valley and Morgan Hot Springs. The longest diameter of the oval depression is about a quarter of a mile and the height of walls and general appearance are similar to those of the old crater on Lassen Peak. There was no indication that fresh lava flows had ever issued from the crater of Bumpass’ Hell; on the contrary, there was strong suggestion that the depression had developed in the old lava by a process the initial stages of which must have strongly resembled the present condition of Lassen Peak.

If the writer were to offer any forecast it would be that the changes going on at the top of Lassen seem likely to form a solfataric basin of the same general character as that of Bumpass’ Hell. However, while there is volcanic life there is a possibility of renewed lava flows. Meantime the physiographer has an opportunity of seeing within the United States, at least one phase of volcanic activity and that on a mountain recently occupied by alpine glaciers and standing in a great lava flow studded with minor volcanic cones, many of them almost untouched by erosion—the whole offering a most inviting field for scientific investigation.