We pulled into the dusty parking lot over a ghostly white road made of the calcium-rich soil unique to the area. As we walked up the trail into the preserve, I could see wind-sculpted juniper trees against the Aspen Mountains. The trees looked as though a whimsical gardener had been at work on them with hedge-trimmers.
It’s peaceful and quiet at Formation Springs – the breeze carries the sweet smell of sage, and many species of wildlife find shelter here among the junipers and willows. We saw deer tracks and heard songbirds rustling through the water birch trees. These springs are an oasis for wildlife, and attract throngs of ducks in the summer – I made a mental note to return then to do some birdwatching. Over thousands of years, the springs have created travertine terraces; travertine is a white crystalline rock formed from calcium carbonate. If you’ve ever seen Mammoth Hot Springs in Yellowstone National Park, you were looking at travertine minerals.
Thinking of that scalding spring, I bent down from the boardwalk path to feel this spring water with my hand – it was shockingly cold. The frigid temperature of the springs reminded me that the water flowing from them dates from the end of the last ice age – this water fell as rain before the invention of agriculture! Using isotopes to age the water, scientists have found it to be around 13,000 years old. The springs have deep pools where the color of the water looks glacial: it’s a turquoise blue against white rock.
As we followed the trail past the ribbon of trees and flowers along the spring, we came to a bowl-shaped area with some non-descript white boulders along the edge. Marilynne knew just where to look, and I finally realized what the flashlights were for. The white rock obscured a cave entrance, just big enough for a person to scramble through. As we entered the cave, the sound became muffled, and the darkness became profound.
I switched on my flashlight. Immediately I could see the cave roof was not made up of the stalactites I had expected, but rather a calcium carbonate surface that, Marilynne mused, looks just like cauliflower. The cave stretches for several hundred feet, and has a few wings, but with a flashlight we couldn’t get lost. Plus, every fifty feet or so, I’d come upon a small porthole to the outside world, which let in welcome fresh air and a little beacon of light. I emerged, blinking, into the bright Idaho sun, feeling lucky to have spent my day in such an amazing part of Idaho’s natural world. Next time I visit, I will be sure to bring my binoculars for the birds and my flashlight for the cauliflower cave. --Sus Danner, protection program manager