I keep meaning to throw a trowel in my pack, but usually a rock or stick work just fine for my needs. We stumbled upon an excavation opportunity on a hike this week, in fact, and used a stick and a couple of rocks to dig up an old railway treasure. Here's a little clip (at the end of a long video):

[video:youtube]http://youtu.be/g7grHEzV240?t=15m6s[/video]