Crater Lake National Park, Oregon

The Pumice Desert: A very thick layer of pumice and ash leading away from Mazama in a northerly direction. Even after thousands of years, this area is largely devoid of plants due to excessive porosity (meaning water drains through quickly) and poor soil composed primarily of regolith.

Mount Thielsen, or Big Cowhorn, is an extinct shield volcano in the Oregon High Cascades, near Mount Bailey. Mount Thielsen stopped erupting 250,000 years ago, and subsequent glacial erosion has formed a horn-like shape. The spire-like shape of Thielsen attracts lightning strikes and causes the formation of fulgurite, an unusual mineral. The prominent horn forms a centerpiece for the Mount Thielsen Wilderness, an area with many recreational activities.