I thought this was going to be a post about your fishing boat sitting on the rocky lake edge !
Great finds from the drivers seat. I would think that in this long drought, if that spring is flowing right now, thats significant....Any reliable water source would have been a magnet for the ancients..the more people the more "litter" they dropped.
Keep a raincoat handy, It ALWAYS rains on the yearly digfest no matter how bad a drought ( October ! )