Examining deposits of pluvial Lake Chewaucan (near Summer Lake, OR

USGS Geologist Richard Waitt examines deposits from pluvial Lake Chewaucan (Pleistocene), near Summer Lake, Oregon. The light colored lines are layers of ash from southern Cascade eruptions that fell on the lake, settled to the bottom and were covered by mud. This sequence likely represents a time period of roughly 50,000 years.