I had a nice view of Bald Mountain in the western part of the Cascades of Skagit County.
The bedrock is volcanic in origin, but this is not the plumbing of an ancient volcano; it is a block of metamorphosed basalt that is surrounded by much weaker metamorphic rocks that have been eroded away. Dave Tucker has a nice write up (fieldtrips/the-high-dome-of-bald-mountain-and-big-rock-too) with references so there is no need for me to repeat. He notes that blocks of resistant rocks sticking up out of softer metamorphic rocks are referred to as "knockers".
The LiDAR of the area shows the Bald Mountain has been partially eroded out by glacial ice having over ridden the area.