Limestone occurs in thick formations near Lava Creek, and in the valley of the East Fork of the Yellowstone river; also near the summit of the Owl Creek range, and in the Wind River range.
Among these may be mentioned Amethyst Mountain, Texas; Yellowstone National Park; Delaware Co., Pennsylvania; Haywood Co., North Carolina; Deer Hill, and Stow, Maine.
In the west of North America, and in some of its islands, a pie is found which extends to the upper valleys of the Missouri and the Yellowstone, and has long been thought entitled to specific distinction as P. hudsonia; but its claim thereto is now disallowed by some of the best ornithologists of the United States, and it can hardly be deemed even a geographical variety of the Old-World form.
In 1832 a steamer ran to the mouth of the Yellowstone, and in 1890 the last commercial trip was made to old Fort Benton (Great Falls), Montana.
That empty into Great Salt Lake, Utah) rises in Yellowstone National Park a few miles from the heads of the Madison fork of the Missouri, which flows to the Gulf of Mexico, and the Green fork of the Colorado, which flows to the Gulf of California.