The Olympic Peninsula in the northern coast of Washington State has a "ghost forest" from when the land level dropped in an ancient earthquake/tsunami event that bounced across the Pacific. Actually, a search on "ancient tsunami buried forest in Washington State" brings up results of "ghost forests" along the west coast. This may be the one I learned about years ago in Geology class. There's a similar place in Oregon where earthquake mud slides or a tsunami dropped debris, burying and killing them. Here is a US Geological Survey paper about that earthquake zone.