Sinkholes are unreasonably complex phenomena – those in rivers doubly so. If you can figure out their geological history, you have a better chance of figuring out how artifacts got there. As far as I can tell, this is not a straight forward task. As time goes by, sinks are subject to slumping, flood deposits, […]

Digging square holes underwater (in low visibility) can get a little ridiculous – it is, however, achievable. To simplify the process, we used an excavation frame built by Jim Dunbar. The design is ingeniously simple. The frame is a two meter by three meter metal grid that can be raised or lowered on poles. Divers […]