Mississippian Waulsortian bioherms in the Big Snowy Mountains, Montana
Mississippian-age Waulsortian bioherms in the Lodgepole Formation are well exposed and accessible for field study in Swimming Woman Canyon, Big Snowy Mountains, Central Montana. Swimming Woman Canyon is east of Judith Gap, northeast of Harlowtown, and north of Rygate, Montana (Fig, 1). The site can be reached by automobile via gravel roads from U.S. 191 or from U.S. 12. Three routes to the site are shown. The route selected will depend on the direction the visitor is traveling. Travelers using the Judith Gap route may be tempted to continue east after driving 15 mi (24 km). Part of the road to the east of this point has been abandoned.
Mileages to turns along the route can be scaled from Figure 1, which is adapted from the Roundup I × 2° Army Map Service (AMS) sheet published by the U.S. Geological Survey. The only other available access map is the Lewis and Clark National Forest (Jefferson Division), Montana, Forest Visitor’s Map (planimetric) at a scale of 1:126,720. No topographic map at a scale larger than 1:250,000 is currently available. The Irene 3 NE 1:24,000 Topographic Quadrangle covers the field area and is in preparation. Travelers may want to keep track of mileage using their automobile odometer while off the main highway. The distances from the various starting points to Swimming Woman Canyon Road are: 25 mi (40.2 km) from Judith Gap, 24.2 mi (38.9 km) from Rygate.
Figures & Tables
Rocky Mountain Section of the Geological Society of America
One of six volumes generated by each GSA section for the Decade of North American Geology (DNAG) project, this Centennial Field Guide contains descriptions of 100 sites or site clusters representing outstanding geologic locations in northern Arizona, Colorado, Idaho, Montana, North Dakota, New Mexico, South Dakota, Utah, Wyoming, and Alberta.