Each volcano type produced by the Anahim hotspot has its own unique life cycle of growth and erosion. Volcanic cones have their origins from tephra accumulating around vents during Strombolian eruptions. They are composed of trachyte, trachyandesite, basalt, phonolite, basanite and to a lesser extent phonotephrite. In contrast, lava domes are formed mainly by viscous trachytic magma that erupts effusively onto the surface and then piles up thick around vents. Most of these features are formed only by a single volcanic eruption and are therefore monogenetic in nature. However, in some cases several eruptions occur at a single locus to create larger, polygenetic centres (e.g. Satah Mountain, Baldface Mountain, Nazko Cone). Once activity has ended, erosion eventually reduces them into volcanic remnants such as lava plugs.