Geyser
Yellowstone is the largest geyser locale, containing thousands of hot springs, and approximately 300 to 500 geysers. It is home to half of the world's total number of geysers in its nine geyser basins. It is located mostly in Wyoming, USA, with small portions in Montana and Idaho. Yellowstone includes the world's tallest active geyser (Steamboat Geyser in Norris Geyser Basin), as well as the renowned Old Faithful Geyser, Beehive Geyser, Giantess Geyser, Lion Geyser, Plume Geyser, Aurum Geyser, Castle Geyser, Sawmill Geyser, Grand Geyser, Oblong Geyser, Giant Geyser, Daisy Geyser, Grotto Geyser, the Fan & Mortar Geysers, & the Riverside Geyser, all in the Upper Geyser Basin which alone contains nearly 180 geysers.
Mount Meager massif
The geomorphology of the Mount Meager massif resembles that of Glacier Peak, another Cascade Arc volcano in the U.S. state of Washington. It consists of at least four overlapping stratovolcanoes that are younger from south to north. With a total volume of , the massif is older than most volcanoes in the Cascade Arc, tracing its history back to 2,200,000 years ago. In the Cascade Range, the oldest volcanoes are generally no more than a million years old. This includes Mount Rainier (500,000 years old), Lassen Peak (25,000 years old), Mount Jefferson (290,000 years old) and Mount St. Helens (50,000 years old). However, portions of the massif formed in the last million years. The volcano is made of volcanic rocks ranging from rhyodacite to basalt. Rhyodacite forms a series of eroded volcanic plugs which form the highest peaks. Their slopes are covered with their eruptive products and serve as the surface expressions of intrusions. As a result, they provide a unique opportunity to study the relationships between magma chambers and their lavas. The mafic (rich in magnesium and iron), intermediate (between mafic and felsic) and felsic (rich in feldspar and quartz) volcanic rocks of the massif were erupted from at least eight volcanic vents.