Specimen Ridge

Specimen Ridge, el. 8,574 feet (2,613 m) is an approximately 8.5-mile (13.7 km) ridge along the south rim of the Lamar Valley in Yellowstone National Park. The ridge separates the Lamar Valley from Mirror Plateau. The ridge is oriented northwest to southeast from the Tower Junction area to Amethyst Mountain. The ridge is known for its abundance of amethyst, opal and petrified wood. It was referred to as Specimen Mountain by local miners and was probably named by prospectors well before 1870. The south side of the ridge is traversed by the 18.8-mile (30.3 km) Specimen Ridge Trail between Tower Junction and Soda Butte Creek. The trail passes through the Petrified Forest^[3] and over the summit of Amethyst Mountain el. 9,614 feet (2,930 m).^[4]

• http://en.wikipedia.org/wiki/Specimen Ridge
• http://petrifiedwoodmuseum.org/SpecimenRidge.htm 
• Page 220 - Dicka, A. B., 2012, 101 American Geo-sites you've gotta see: Mountain Press Publishing Co., 250p.