I’d say that’s a reject preform. You can see the bad spot I circled. The knapper tried to overcome bad spot but couldn’t. He reduced the width toward the base in an attempt to fix it but failed. He could have fixed it by chipping from the base, but he would have lost the length he needed. I’ve been a knapper since 1985 and know what I’m looking at.
Nice sized biface. If found on a site that has produced only paleo age diagnostic artifacts then you have a valid context. If not found in context it could easily be a biface from a later culture. A couple of Smoky Hill silicified chalk bifaces I have found that are Late Prehistoric in age.
First, The type of reduction including overshots and I thought it was Paleo. Second, I sent it to Ben Stermer whose specialty is artifacts from the Great Basin and he typed it as a Paleo Blade
Dennis, Its very different than the usual trade blanks from the Basin. It's a difficult material for me to get good pictures but this piece had some fine edge work where trade blanks don't.