The eastern part of the park is a different volcanic composition. Bumpass is dacite which is similar to rhyolite. The thicker magma clogs vents and builds up back pressure leading to explosive volcanic events. This is not an explosive magma. There is some gas associated with basalts.
Basaltic flows can go for miles.
Near the vent bombs and lapilli build up a cinder cone. Cinder cones erode easily so if you see a nice cinder cone it is recent. In the throat of the cinder cone is a neck of lava. This cinder cone is 800 feet above the lava flows below. This cone erupted less than 300 years ago, possibly in 1851 when there were immigrant reports of fires in this region.