Bruce, thanks for another very fine capture of this natural/geological phenomenon, and thanks too for the explaining narrative.
Wiki and you have done a very interesting match, because I was unknown of the existence of this unusual rock formation of columnar basalt, Buddy!

This is what the sides of Devils Tower in Wyoming looks like, essentially an interior column of lava, cooled in place inside a volcano, then the outer soil eroded away. I've also seen and photographed lines of columns very much like this, visible on the north side of the Yellowstone River, in the far northern portion of Yellowstone National Park. Cascading cliffs that start very high and run down to the river, with two thick lines of these basalt columns, the upper line deposited during the last eruption of the mega-volcano under Yellowstone Lake, approx. 640,000 years ago, and the lower one, approx. 1.2 million years ago. Your monument, Bruce, has to be the remainder of some severe volcanic event, far back in California's history. A very cool shot, indeed, and the geologists I worked with for over thirty years would love being right where you were.