There is an artical in The Oregonian this morning about the excavation of "Fort Yamhill" near McMinville, Oregon, that stood from 1856 until it was closed at the end of the Civil War in 1866. It was built to serve as a buffer between Native Americans and the hostility of settlers. A diary exists by Cpl Royal A. Bensell in which he states:
August 25, 1862
Weather extremely hot...Kengorn, Magician, exhibited his slight-of-hand tricks in the mess room. A large audience of admiring Oregonians. Tho' nothing extra, it was quite a relief from the usual monotomy.
Check out http://blog.oregonlive.com/multimedia for more information about the dig.