Mammoth Hot Springs
If the dates on the captions are accurate, our travelers arrived at Mammoth Hot Springs on August 18th 1889 (having left Bismarck, ND that morning) and stayed one day seeing the sights.
These photographs documented the members of the party. In the Rival Kodak pictures, presumably James Sibley Watson took the picture of Emily Sibley Averell, and Emily took the picture of the entire group, with Jimmie shooting simultaneously. They repeated this simultaneous photography in later trips.
There were several extinct geysers in the Mammoth Area. This may be McCartney's Cave, which was described in Guptill's 1890 Practical Guide to Yellowstone National Park on p. 19-20:
"About 500 feet distant from the [Mammoth Hot Springs] hotel may be seen a conspicuous fence surrounding three sides of what is known as McCartney's Cave. This is an irregular opening in the level surface of the plateau some four feet in daimeter; it is visited by many for the purpose of examining the ancient hot water stratified deposits plainly indicated throughout the cave. Called a cave, it is simply the crater of an extinct geyser or hot spring. By means of a ladder one can descend vertically some 30 feet to the first level; thence 20 feet on an incline to the bottom of this chamber with perfect safety. The venturesome may, by means of a rope and light, continue explorations 100 feet further without, ordinarily, experiencing much discomfort fromt eh carbonic acid gas not perceptible in the first chamber. Far beneath, in a subterranean chamber, water can be distinctly heard by the rope-supported tourist; but the hot vapors and gases constantly arising discourage further investigation, and stimulate an earnest desire to ascent to the surface."
This may be J.G. Averell pictured on the ladder.
Who were Montana and Big Medicine Man?
Around the time of this trip Emily Sibley Averell and James Sibley Watson, Sr. began exchanging letters addressed to one another as "Wyoming" (Emily) and "Colorado" (Jimmie). Could this couple also have been using nicknames?