Lava Beds National Monument Butte is just outside the boundary of the monument, the Callahan flow is in Lava Beds and is the youngest flow in the monument. Spatter cones are built out of thicker lava. The lava is thrown out of the vent and builds, layer by layer, a chimney surrounding the vent. Fleener Chimneys and Black Crater are examples of spatter cones. Roughly ninety percent of the lava in the Lava Beds Monument is basaltic. There are primarily two kinds of basaltic lava flows: pahoehoe and 'a'a. Pahoehoe is smooth, often ropy and is the most common type of lava in Lava
Boring Lava Field quartzite-pebble xenoliths (rock fragments enveloped in a larger rock during the latter's development and solidification) can be observed among local cinder specimens, dating from Miocene to Pliocene Troutdale deposits. While the volcanic rock of Boring Lava was being emplaced over rock from the Troutdale formation, there was deformation that uplifted and dropped fault blocks to the southeast of Portland. Along the Washougal River, a large landslide occurred as a result of failure due to the Boring lava pushing down on rock from the Troutdale formation. Intrusions of Boring Lava formed outcrops at Highland Butte, La Butte, and potentially in the