Geology
The forest is one of the northernmost sections of the Highlands Province of the Appalachian Mountains. The Precambrian gneiss bedrock in the forest is the oldest in New York State, formed 1.1 billion-1.3 billion years ago and first uplifted during the Taconic Orogeny 460 million-440 million years ago. The Acadian and Alleghenian orogenies further shaped the mountains to their present form, and then the glaciers and erosion wore them down.
Within the gneiss can be found several other minerals: feldspar, quartz, pyroxene and mica. Black bands within the bedrock come from the mineral that gave the forest its name: magnetite, a source of iron. Two plane crashes on the Hill of Pines, less than 600 feet (180 m) apart, are believed to have occurred because of the mineral's influence on the aircraft compasses.
Read more about this topic: Black Rock Forest