Like the fungi post of a couple days ago, here is another example of my not noticing things. I've been along this trail dozens of times and never saw this. I mean, it's right there! Oh well, being a person who always tries to put a positive spin on an otherwise unpleasant situation, I just look at my not noticing as leaving room for new discoveries.
There are quite of few of these hollowed out areas in Annadel Park. These hollows are left over from when cobblestone was quarried and used in the building of San Francisco and other west coast cities, as well in their reconstruction after the 1906 earthquake. However, cobblestone roads were not suitable for motorized vehicles, and by the 1920's demand for cobblestone declined. This hollow is different from the rest in that it has this small tin roof shelter, for what purpose it had, I don't know. There is no smoke residue and its too small to sleep in.
Sinbad and I will be away for a few days, off to the desert for peace and relaxation.
I think I can find my way okay.
Be back later next week with new tales of misadventure.