Stems and branches are stout. Younger stems covered with a copper pubescence. Large leaf scars, terminal bud pointed, lateral buds smaller.
Flowers are on separate inflorescences, males in long drooping catkins.
Fruit is a nut, or a dry drupe. Covered with a green husk most of the summer you can tell when they are ripening as the squirrels start eating them. They have a very think "shell" with almost no meat inside. Lot of work compared to an English walnut.
Comparison with an English walnut on the right.
Not really know for great fall color, they do color up pretty well if it gets cold enough, but not too cold.
Most likely the CA walnut which has fewer leaflets that tend to be smaller.
Aptos Beach Road and Bayview Ct.
110 Central Ave (Depot Hill)
Cedar St just by Center St.