I salvaged a old (about 1840's) hand blown beer bottle. The only artifact I kept, we stopped working for about a week. The school and a museum hand dug that entire dump site finding many artifacts. The delay cost us money, but it was the legal, responsible and the right thing to do.
I agree. You did the right thing.

Working for an old excavating contractor 20 some years ago, on an addition to a local high school, and he took us aside and very quietly told us, "They say there's a possibility of some Indian burial grounds on this site, and if we find anything, we're to stop work so some archeologists can check it out. If you see anything like that, I want you to cover it back up and keep on going. We don't have time for that ****."





Fortunately, the only unexpected thing we ran into was three big old septic tanks from the school.