Digging Up History in the Sawtooth N.R.A.

When I took the job at the Stanley Museum, I never expected that I would be using my geology knowledge as much as I have this summer. I expected to enlighten folks with information regarding the mining in the Stanley Basin and up the Yankee Fork, but little did I know that I would use my geoscience degree on a daily basis. The Sawtooths have a unique front that can compete with many of the National Parks that are in the Northwestern United States, such as Glacier and the Grand Tetons. With the jagged faces and obvious ‘saw like’ peaks, many folks come into the museum taking a step back (mostly taking photos) and asking how the mountain range could have formed.

When discussing Stanley’s mining days, many had their sights on a different kind of geology. Gold. Most of the prospecting occured in the Stanley Basin, just up and over the hill from the museum site. Few struck it rich, but many tried. The remnants can be seen in the creeks of Joe’s Gulch and in the remaining cabins that are speckled throughout the basin, or at least what is left of them. Mining in the area proved to be extremely difficult through the robber’s clay (which is a fine grain clay that restricts the gold from concentrating) that makes up much of the soil and alluvium in the basin. The amount of ingenuity and determination to extract the gold from the thick clay can be seen in various pictures around the museum, from the single gold panners in the creeks to the Willis Dredge that dug up bed rock and river deposits all up the gulch. All of these prospects soon slowly became part of the earth that they originally tore up.

Yet, I rarely get any questions on the where to find gold and how it was extracted. Now with the wilderness protected and the prohibition of mining in the wilderness, many folks simply are interested in the beauty of the geology, rather than the value of the mineral. We are in the Gem State, after all. Many end up asking me questions regarding the formation of the Sawtooths, or why they look so different from the White Cloud Mountain Range even when they are right across the highway from one another. Idaho’s geology is amazingly complicated, and so in comparison the Idaho Batholith that makes up the Sawtooths is relatively dull.

The Idaho Batholith is mostly composed of granite and granodiorite from the Cretaceous period, but what many don’t realize is that there is a smaller batholith in the vicinity of Redfish Lake. The Sawtooth Batholith is about 50 million years old and the granite has more of a pinkish tone. But what I found most interesting this summer, when I hiked up to Thompson Peak, was taking a closer look at the Thompson Peak Schist. There is no current evidence for the age of this formation. From the base of Thompson, you can see the individual layers of this metamorphic rock, with deep reds and oranges to light greys and white sections.

Whether you have a geology degree or not, anyone can enjoy the geologic beauty of this amazing area. I personally love talking with people and attempting to explain the massive processes that made the Sawtooths what they are today. I always love looking out the windows in the museum, admiring their glory from afar.

Liz Crowther

Historic Specialist, Stanley Museum