Cool find. There were a few sailing vessels brought up for use on the Sacramento River during the goldrush, the wrecks of two or three can be dived today. I've seen similar dead-eyes recovered from some Great Lakes wrecks in similar condition (fresh water finds are so nice!). Aside from coming from a sailing vessel, it's anyone's guess as to it's origin. You can have the wood tested/typed, but it would likely be identified as lignum vitae aka ironwood used universally for deadeyes, sheeves and similar applications. Usually, a single band of iron is wrapped around the deadeye, but yours has two rods. This may have some significance, but is likely from a smaller vessel. Regardless, it's a rare find in a state where nearly all of its wrecks stranded and were pulverized in the surf.
