Driving south trough the Black Hills of South Dakota is a relaxing experience.  The roads are winding and there’s little traffic, with dark but widely spaced pine trees on all sides, and there are occasional river crossings and camp sites.  I saw more bison warning signs, although I never saw the bison, and the idea of them wandering though this dark forested landscape gave the place a primeval feel.  I could almost see what it would have been like here before the presence of humans.

But a bit further south the landscape opened up again into the sweeping grasslands that I’ve come to admire so much.  This was Wind Cave National Park, although the cave system itself is only a part of the attraction.  On the surface I found rolling hills that I could wander for days, hearing only the hiss of the wind in the grass, and the  chirping of birds.

I went to the visitor’s center, which I found by following the directions on the park’s web site.  They also give this warning which, considering my ongoing war with my GPS, made me laugh.  At least I’m not the only one!

I signed up for a ‘Natural Entrance’ tour there, and wandered around looking at the interpretive information while I waited for it to begin.  It seems that Wind Cave was known to the Lakota Indians, who considered it the entrance to the spirit world, and believed that the entrance to the cave is where mankind emerged into the world.  We were asked to respect the site as it still retained spiritual significance for the Lakota.  The cave system is apparently one of the most complex in the world, carved out of limestone.  You can see that complexity in the map of the passages — these known passages are believed to only a small percentage of the cave still to be discovered.

Our tour leader was Ranger Kelly, who had a very infectious passion for the cave system.  In fact, I have to commend the National Parks Department, because every ranger I’ve met so far has been extremely knowledgeable about their parks, and passionate about their preservation and educating the public.  They make visiting these place a remarkable experience!

The first thing Ranger Kelly showed us was the natural entrance to the cave, from which a strong cool breeze was blowing.  It seems that the wind changes direction depending on the relative atmospheric pressures in the cave and externally, and it was this breeze that led both the Lakota and the first white explorers to the location of the entrance.

After going through an airlock to preserve the relative pressures, we descended several flights of stairs into the cave, and followed a concrete pathway through the passages.  We had two rules: 1. don’t touch the cave walls or formations, and 2. stay together as a group.  The cave was lit to show up the formations, but at one point the lights were turned out so that we could experience the total darkness.

The primary formation for which Wind Cave is known is called boxwork.  In fact, 90% of the known boxwork in the world is in Wind Cave, and much of the rest is in other caves in the Black Hills.  It seems that cracks in the limestone were originally filled in with a harder calcite, and then, when acid water seeped into the cave and ate away the limestone, the calcite was left.  Ranger Kelly compared this to building a wall with sugar cubes and mortar instead of bricks and mortar — when the sugar cubes dissolve, only the mortar is left.  In this way, these are not what are usually thought of as cave formations, but were in fact present beforehand, and only revealed when the cave was created.  Interestingly, there was never any flowing water in these caves, but the seeping ground water filled and drained from them at least eight times.

Ranger Kelly also did a great job of explaining how the Civilian Conservation Corps (CCC — see my Letchworth State Park post) were responsible for many of the improvements to the park, both above and below ground, including the original cement stairs and walkways, the lighting, and the elevator shaft that took us back to the surface, and that was carved out over 200 feet deep by hand.

Much as I enjoyed exploring the cave, for me the really amazing aspect of the park was the grassland up above.  Since I wasn’t in any hurry, I sat there watching the breeze send ripples though the grasses as a storm rolled across the sky.  I was sorely tempted to just walk off into the grass and get lost in the hills for days… I think maybe I’ll come back here someday and do just that.  I don’t know if I’ve ever seen a more peaceful place…