Seigler Mountain is one of the mountains in the Cobb Mountain Area, which have a volcanic origin. Others are
Cobb Mountain, the most dominant,
Mount Hannah and
Boggs Mountain. There are isolated small valleys and basins between the mountain peaks. Seigler Mountain is separated from Mount Hannah by Salminas Basin, a large mountain meadow with an unusual complex of wetlands that feeds Cole Creek. Flows of porphyritic lavas from Mount Hannah and Seigler Mountain cover about . The mountain was volcanically active 600,000 years ago, and flows from the mountain overlaid white bedded tuff to the north of
Howard Springs. ==Ecology==