In the style of proper Mojo excess, reader ATMachine has, erm, dug up quite a few notable pieces of concept art, mockups, and screenshots from really early versions of The Dig. Some of the art is from early versions of Sean Clark's take on The Dig (which ended up eventually being the one which shipped), while some are from Brian Moriarty's version (Brian Moriarty, mostly known to LucasArts fans for the creation of Loom, worked on one of the many versions of The Dig as its development progressed over the span of the mid-90s).<:MORENEWS:>
Included in ATMachines most recent finds are some interesting things including an alternate version of The Dig's notorious "bone puzzle," some odd user interface concepts, and many rooms completely cut from the final game.
This is actually the second batch of screenshots from ATMachine. His first thread containing the other finds is here.