When Philetus W. Norris assumed the park superintendent position, he created a map in 1880 designating the area as “West Thumb.” Park officials in the early 1900s later attempted to resurrect the “West Arm” title, but popular opinion refused to budge from the well-recognized “West Thumb” distinction.

West Thumb Geyser Basin
Renowned for its scenic geysers situated beneath Yellowstone Lake’s surface, on the lake’s shoreline, and across the surrounding landscape, the West Thumb Geyser Basin instills intrigue with its multi-colored clay and spewing fountains. The West Thumb Geyser Basin is also recognized as the first Yellowstone area to be described in a publication.

Trapper Daniel T. Potts sent a letter to his brother in Philadelphia, Pennsylvania describing the unique features of what is now known as Potts Basin. His edited letter subsequently appeared in the September 27, 1827 issue of the Philadelphia Gazette.

Further reports of the area were not available until after the 1869 Folsom-Cook-Peterson Expedition. Later, stagecoaches escorted tourists eager to see the area’s pale violet waters and deep springs. As the park became more modernized, traffic to West Thumb Geyser Basin increased, and a campground, cabins, cafeteria, gas station, and photo shop were added to capitalize on the growing number of visitors. Eventually, however, park officials noted that the increased traffic and area services were actually destroying what people had come to see. In the mid 1980s, the National Park Service removed all buildings and services from the West Thumb Geyser Basin in an effort to protect and preserve the beautiful area. Today, boardwalks in the basin protect the area’s features and its visitors.

Abyss Pool
In 1935, Chief Park Naturalist C.M. Bauer named Abyss Pool, a hot spring of the West Thumb Geyser Basin, for its impressive deepness. Bauer may have taken the name from Lieutenant G.C. Doane’s 1870 description of a spring in this area: "the distance to which objects are visible down in [its] deep abysses is truly wonderful" (Bonney and Bonney, Battle Drums, p. 330). Abyss Pool may also be the spring that visitors referred to during the 1880s as "Tapering Spring" because of its sloping walls.

Nineteenth century observers were impressed with the pool’s beauty. In 1871, F.V. Hayden reported that this spring’s "ultramarine hue of the transparent depth in the bright sunlight was the most dazzlingly beautiful sight I have ever beheld" (Preliminary Reports, p. 101). And W.W. Wylie observed in 1882 that the spring’s walls, "coral-like in formation and singular in shape, tinted by the water’s color, are surely good representations of fairy palaces".