Sea Stack Pining for the Sea

One of the first roadside zomg-look-at-the-scenery pullouts at the northern end of Cape Disappointment State Park happens to overlook a wonderful example of what happens when sediment fills in the sea round a sea stack. Can you spot it?

Image is looking out to sea. In the foreground are trees, some snags, and a knob of rock. Beyond it is a flat area covered with vegetation and a strip of sandy beach beyond.

Lonely Sea Stack is Lonely

This is the result when a nice, hard stack of basalt (in this case the Eocene Crescent Formation basalt) ends up in a sea of sediment instead of a sea of saltwater. Poor thing is now stuck inland. The only time it’ll be a stack again is either during a tsunami or if sea level rises.

Image shows a closer view of the top of the former sea stack, which has grown a mantle of moss, grass, and possibly a tree.

Let’s Call it Broody.

There’s probably some technical term for these things. I thought it was “knocker,” but that seems to only refer to knobs of rock within a melange. And my brief attempt to wrestle an answer out of Google was non-successful. Who here knows what they’re technically called?

If there is no technical term, I call dibs on calling them “broodies,” just in case that catches on.


  1. Trebuchet says

    Not all that far north of there, near Tokeland, a whole lighthouse and small community were washed into the ocean at the north side of the entrance to Willapa Bay. The sea giveth, and the sea taketh away.

    The Gray’s Harbor Lighthouse, in Westport, is now about a mile from the sea after having been built pretty much right on the beach.

  2. Trebuchet says

    Forgot to add: The broodie is cool. At least it’s not pinin’ for the fjords.

  3. lyle says

    A coast with cliffs is an emergent coastline (which most of the US west coast is). For one reason or another sea level is dropping relative to the land. Old sea cliffs and beaches rise above the level of the water and are left So you had uplift which allowed the sediment to fill in. Sea Cliffs Arches etc are signs of an emergent coastline. Consider the SE US as a submergent coastline with big estuaries (for example Chesapeake Bay is really the Susquehanna river valley with the Potomac, James, etc rivers as tributaries) , flat etc. (here relative sea level is rising).

  4. Trebuchet says

    @4, lyle:
    So apparently, the whole country is tilting to the right! And the biggest AGW deniers will be the first to be flooded.