Holy molé!! Found this yesterday bushwacking down to the American River from F.H. Divide. I don't know if it's a knife or spearpoint but it's almost as big as my hand.
When you say "bushwacking down to the American River" does this mean traversing up and down the hillsides or at the actual river itself?
What was the context of the find?
If at the river, was this a sandbar or river back find?
If on the hillside, was it a plataue type of location?
Any other appearance of habitation?
Did you find this on top of the surface?
There appears to be a beveled edge visible, along the bottom side by your fingers, judging from the shading of the relic in the photo. While the top edge cant be seen to determine if its beveled since this edge is on the side not visible, I would say its likely beveled as well. The bevel normally stops close to the wide hafting area.
I would say that you found a Cobbs Triangular knife. Cobbs Knife are 8000-5000 B.P. Early to Mid Archaic
Therefore if you have a rhomboid cross section of this relic, its likely a Cobbs Knife.
I have never head of one being found that far west. Typical location is Midwest to Southeastern States
Is the relic beveled on one or both edges?
Does the bevel stop close to the wide hafting area?
Is the relic ground on any of the edges?
Are those spokeshaves or chips on the edge? There appears to be one on each side. Are there any secondary percussion flaking in these areas?