Reports from the Washburn Expedition of 1870 stimulated so much interest in the Upper Yellowstone that the U.S. Government decided to send two expedition to explore the area systematically the next year. One was under the direction of Dr. Ferdinand V. Haden of the U.S. Geological Survey, and another was under Colonel John W. Barlow of the Army Corp of Engineers. The two expeditions worked in tandem to measure and map the wonders of the area. One of those wonders was “Soda Mountain,” what is now known as Mammoth Hot Springs.
In an era when water for bathing often was heated in a teakettle, the copious amount of hot water flowing down the mountainside at Mammoth Hot Springs intrigued the explorers. Here’s how Colonel Barlow described it.
A system of hot springs of great beauty, flowing from the top and sides of a large hill of calcareous deposit, and called Soda Mountain, is found five miles up the left bank of Gardners River. Here, at the foot of this curious white mountain, we encamped, and remained until the 24th [of July], examining the wonderful spring formation of this region, and the country around it.
The central point of interest is the Soda Mountain, occupying an area of a hundred acres, and rising like the successive steps of a cascade, to the height of over 200 feet above the plateau at its base. The upper surface is a plain, composed of many hot springs, constantly sending up volumes of vapor slightly impregnated with sulphurous fumes.
The sides of the hill down which the waters of these hot springs flow have become terraced into steps of various heights and widths, some twelve inches in dimension, while others are as many feet. In each terrace there is generally a pool of water, standing in a scalloped basin of gypsum, deposited at the edges by the water as it becomes cooler. These basins are often tinged with pink, gray, and yellow colors, giving to the whole a very beautiful effect.
The rock in all directions has evidently been deposited in the same manner as the Soda Mountain is now being built up. When the formation ceases from a change in the course of the water, the rock becomes friable and disintegrates. After a time vegetation springs up and covers the surface. Many of the basins have the size and shape of bathtubs, and were used by members of the party for bathing purposes. The temperature varies in the different pools from fifty degrees all the way up to one hundred and eighty, so there is no difficulty in finding a bath of suitable temperature.
[A few days later, Barlow left Mammoth Hot Springs to explore the area. When he returned in again enjoyed the hot water again.]
Toward evening I enjoyed a bath among the natural basins of Soda Mountain. The temperature was delightful, and could be regulated at pleasure by simply stepping from one basin to another. They were even quite luxurious, being lined with spongy gypsum, soft and pleasant to the touch. I walked over a part of the hill by the faint light of the new moon, which gave to its deep-blue pools of steaming water a wild and ghostly appearance. The photographer has taken numerous views of these springs and the country in their vicinity, which will serve to convey a much more definite idea of their beautiful formation than can be given by any written description. A special survey was made of this locality, and careful observations of its latitude and longitude.
—Excerpts from Colonel John W. Barlow, Report of a Reconnaissance of the Basin of the Upper Yellowstone in 1871, U.A. 42d Cong. 2d sess. Senate Ex Doc. 66, 1871, pp. 2-43.
— Illustration from William Wallace Wylie, Yellowstone Park, or The Great American Wonderland. Kansas City, Missouri: Ramsey Millett & Hudson, 1882. Based on a Henry B. Calfee photograph.
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