Boring Lava Field

The Boring Lava Field is an extinct Plio-Pleistocene volcanic field zone with at least 32 cinder cones and small shield volcanoes lying within a radius of 13 miles (21 km) of Kelly Butte, which is approximately 4 miles (6 km) east of downtown Portland, Oregon, in the United States. The name is derived from the town of Boring, Oregon, which lies just to the southeast of the most dense cluster of lava vents. The zone became active at least 2.7 million years ago, and has been extinct for about 300,000 years.

• http://en.wikipedia.org/wiki/Boring Lava Field