The Four Birds Trail is located in Rockaway Township NJ. Marked with white blazes, it runs from the base of the Greenpond Mountain, near the New Foundland Train Station (abandoned) and terminates at the parking lot for the Wildcat Ridge Wildlife Management Area on Greenpond Road in Hibernia. Greenpond Mountain is comprised of the purple hued conglomerate rock layers commonly known as puddingstone in the Morris County area. The trail continues over Copperas mountain and south along the western edge of Splitrock Reservoir. This northern stretch is lightly travelled and the blazes are difficult to find in some spots. Iron ore mining was the predominent industry in this region during the 1800s and into the early 20th century. The entrance to the Hibernia mine near the end of the trail (or beginning) is now blocked off, but functions as a hiberniculum for bats. In the summer heat the cool air from the mineshaft blows about twenty degrees cooler than the normal air temperature. The trail is mostly single track and very rocky.
https://en.wikipedia.org/wiki/Hibernia_mines
https://en.wikipedia.org/wiki/Splitrock_Reservoir
