Petrified Sea Gardens

Petrified Sea Gardens, also once known as Ritchie Park, is a National Historic Landmark on Petrified Sea Gardens Road in Saratoga Springs, New York. It preserves a bed of ancient stromatolites in a Cambrian rock layer, which were the first to be recognized and understood for what they are. The site was a private park open to the public for many years, but is now closed. The site was designated a National Natural Landmark in 1967, and a National Historic Landmark in 1999.

Source: Wikipedia