Lying just on the northern flank of Hoodoo Mountain is a small tuya known as Little Bear Mountain. This related Pleistocene age subglacial volcano consists of alkaline basalt and erupted mainly pyroclastic breccia with minor amounts of massive lava, pillow lava, volcanic sandstone and hyaloclastite. Cross-cutting veinlets of obsidian indicate these volcanics were formed by partial melting in the mantle beneath Little Bear Mountain. Mantle xenoliths found at Little Bear Mountain may have originated from mid-crustal depths.