Thanks everyone. I posted those same pics over on the What Is It? forum and gunsil identified the knife as being made by Edward Barnes and Sons of Sheffield, England. They ceased operation in 1888 so the knife is at least that old. No military affiliation. Gotta love the collective knowledge on this site! Soon I'm going to post some of the other items I have found in the same area. Nothing rare or valuable, just interesting. The site had never been detected before.