NP-YEL 8749 Myriad Group, Upper Geyser Basin. Approx. 1113 features from Three Sisters Springs to The Ruins were mapped in this group in late 1959. The most detailed map of this area of the Upper Geyser Basin of Yellowstone National Park. Somewhat grainy B&W copy will be shipped unfolded. 24″x34″ 13 Oz.