Hey Crusher, (speaking of northern california) you know what the name of the town was under Lake Almanor?
The lake is only 90' deep at it's deepest places. The locals said they could still see sunlight reflecting off the old tin roofs of the buildings underwater, and a few different times my father said he found stange radar readings on the fish-finder.
He thought they could have been buildings or foundations.
I know there's a graveyard they had to move for the town to higher ground.
Also, Bayocean in Oregon (Tillamook county) was re-claimed by the ocean. The pennensula it was built on apparantly lacked sea-walls, and the sand eroded after a series of storms, undermining the buildings. Today the pennensula is thinner, but home to a bird sanctuary.