Look what I found! I think these are walnuts. The trees are about half a mile from my house, and appear to be part of an abandonned orchard. They border the U.C. Hansen Trust property on Saticoy Avenue which was sold last March to be developed into houses and condos. It will be sad to see these lovely old trees go.
If these are walnuts, the outer husks should give a deep brown color — almost black. I brought a bag of them home and I’m going to boil them up and see what I get.