Deception Pass on this excellent geology-oriented blog.
- Much of Puget Sound is nothing but Pleistocene - with Vashon glacial deposits on the surface and older glacial and interglacial sediments peaking out from the lower portions of some of the bluffs. But at Rocky Point, on the west side of Whidbey Island, and in Skagit Bay, the Mesozoic re-emerges from the basement to form rocky islands and headlands.