age. There is a small amount of andesite in the lavas from the field, mostly erupted from monogenetic vents or Larch Mountain. Sometimes, Boring Lava overlaps with volcaniclastic conglomerate from other Cascade eruptions in Multnomah County and the northern part of Clackamas County. The Boring Lava also contains tuff, cinder, and scoria; it is characterized by plagioclase laths that show a pilotaxitic texture with spaces between them that show a diktytaxitic texture. The Boring Lava exposures show aeromagnetic anomalies with short wavelengths and high amplitudes suggestive of their relatively young geological ages. At points where the Boring Lava sits over Troutdale Formation deposits, landslides are frequent, producing steep head scarps with heights of up to . These scarps tend to have grabens at their bases and Boring Lava blocks at their tops, and they show variable slide surfaces from hummocky to flat. A number of these exposures show dips up to 35 degrees, as well as minor faults. The landslides range in thickness from . Portland's wet climate leads to weathering, which at the Boring Lava Field has reached depths of up to , altering the upper of soil to a red, clay-like material. At the cinder cone in Mount Tabor Park, an outcrop of 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 subsurface regions near Aurora and Curtis, and these intrusions have been associated with normal faulting at Parrett and Petes Mountain, Aurora, Curtis, and Swan Island (along the Molalla River). Faults together with igneous intrusions are usually accompanied by stretching and doming as a result of magma influxes or collapses from the evacuation of the magma flows. Similarly, faults north of Oregon City might have resulted from subsidence after magma chambers emptied or lava was extruded as a result of Boring Lava eruptions. Some of the Boring Lava vents cut off hydrogeologic units in the surrounding