It was the keystone (the top-most stone) in the arch which spanned from the New England to the Southern colonies, the keystone of the union. Or it was the necessary keystone in the process of ...

A keystone in an arch's crown secures the other stones in place. Keystone species play the same role in many ecological communities by maintaining the structure and integrity of the community.

The Western Mass. Hilltown Hikers will hold its annual fall group hike of the historic Keystone Arch Bridge Trail from 10 a.m. to 2:30 p.m. Saturday, Oct. 22. The moderate hike totals five miles and ...