Tripod Rock

Tripod Rock, or 3 Pillar Rock, is a glacial erratic or "perched boulder", located in the Pyramid Mountain Natural Historical Area. The Precambrain gneiss boulder, estimated at 127 metric tons (140 tons), is 19-feet long, 10-feet wide, and 7.5-feet high and balanced on three smaller boulders spread roughly 3-feet in diameter that raise it 1.5 feet off the ground. While there is no evidence that Tripod Rock was ever used as a solar observatory, the line of site formed through two large boulders 36-feet to the northwest forms the summer solstice sunset.

Pyramid Mountain Natural Historic Area, established in 1987, spans more than 1,500 acres of open space with unique geological attributes. Its wide variety of natural habitats including fields, forests, streams and ponds, support a number of plants considered uncommon to New Jersey as well as threatened and endangered plants and animals.

Image copyright: wallyg (Wally Gobetz), hosted on Flickr and displayed under the terms of their API.