Of these, Lassen's Butte is the highest, being nearly 11,000 feet above sea-level.

Miles of its flanks are reeking and bubbling with hot springs, many of them so boisterous and sulphurous they seem over ready to become spouting geysers like those of the Yellowstone.
The Cinder Cone near marks the most recent volcanic eruption in the Sierra.

It is a symmetrical truncated cone about 700 feet high, covered with gray cinders and ashes, and has a regular unchanged crater on its summit, in which a few small Two-leaved Pines are growing.

These show that the age of the cone is not less than eighty years.

It stands between two lakes, which a short time ago were one.