W Scott White
The northern section of the Big Spring Creek Trail (Gallatin National Forest #191) is incorrect.  At the intersection of the Big Spring Creek and Skyline Trails (#151), this northern trail was proposed by the FS in the early 2000s but was never constructed.  The correct trail, connecting the Big Spring Creek, Skyline, and Sage Creek (#11) trails, is shown on the Sunshine Point Montana 7.5' topo map (USGS) and the Forest Service's FS Topo website.  I can provide more details, URLs, and GIS maps.