1958 Map of Porphyry Reef

About this map

The Continental Divide serves as the literal spine of this 1958 field-checked landscape, marking the boundary where Flathead National Forest meets the Lewis and Clark National Forest. This high-altitude terrain is characterized by massive geological formations including the Washboard Reef and Porphyry Reef, where steep limestone walls create a formidable natural barrier. Human presence is limited to the administrative and survival networks of the mid-century wilderness, anchored by the Wrong Creek Guard Station and a series of high mountain crossings like Sun River Pass and Teton Pass. The survey records a primitive transportation network consisting of a Pack Trail system that follows watercourses like Mc Donald Creek and Bowl Creek. This map captures a strictly protected environment, showing the intersection of three counties and a dedicated Game Preserve area centered around the headwaters of the North Fork Sun River.