Buck Santistevan is the archeologist on site for the Alaska Department of Transportation’s extension of the Sitka Seawalk. (KCAW/Salemo) A collection of historic finds rests in the bed of Buck Santistevan’s pick-up truck. Donning a neon vest and hard hat, they point out the items they have found so far. “That’s the exhaust. This is the mooring chain. That’s the keyhole anchor.” Each of these objects were buried under decades of sand and mud pack…