Trader Mountain is a small dacitic stratocone-like feature with an extrusive
dome;
lava flows dip away from the center in all directions (Chris Nye, oral commun., 2007). Wilson and others (1995) alternatively describe Trader Mountain as a hypabyssal
dacite plug, and report a "potassium-argon age of 0.98+/- 0.05 Ma (F.H. Wilson and Nora Shew, unpub. data, 1988)."