Fellow Idaho Treasure Hunter member, Brett, brought me one of his latest finds while metal detecting in a Boise park and I thought the item was unique enough to be worthy of a post.  Brett found it with his 25+ year old Bounty Hunter detector, and it sang like a bird when he swung over the target.  He said it was barely covered with dirt, so obviously wasn't there for very long.  The disc is brass, a whopping 3 1/2" in diameter and weighs 10.9 ounces!

 

The Capital Memorial Bridge was built in 1931 by the Morrison-Knudsen company.  The concrete arch of the bridge is a memorial to the Oregon Trail pioneers that crossed the Boise River close to where the bridge stands.  According to my research, the Oregon Trail continues on through what is now Ann Morrison Park where the baseball diamonds are located.commemoritive disc

 

I have been unable to find any information about the disc, or the significance of the dates 1931-1992.  Obviously, the the first date signifies the year the Capital Memorial Bridge was built, but the 1992 date is puzzling.  If anyone has information about the disc please leave a comment.