Looks to me like an early-stage preform for a large Archaic point that was abandoned because that bad chunk broke out of it during the process. You can see where a striking platform was being set up to take some of that thick hump off the basal end.
A piece of stone that is in the process of being shaped and knapped into a point, knife, or other tool-an unfinished point, if you will. Often they would go to a quarry, spall off chunks of rock, and make them into early-stage preforms before carrying them back home to save weight and test the quality of the stone. They would sometimes cache big bunches of preforms to pick up and finish later, also.