Rock of the Glen roadside turnout with historical marker sign Paved turnout, south side of highway. 'Rock of Glen - On July 26, 1842, John C. Freemont's first expedition to the far West guided by Kit Carson with Joseph Bissonette as interpreter. Also Al Maxwell, as hunter, camped in this rocky glen. Names and dates of many of the 300,000 travellers of the Oregon Trail are here.' Area with names of these travellors - 200 yards South of highway. - Photo, looking south at Rock of the Glen from highway turnout. With half of the earth’s geothermal features, Yellowstone holds the planet’s most diverse and intact collection of geysers, hot springs, mudpots, and fumaroles. Its more than 300 geysers make up two thirds of all those found on earth.