August 5- Got up early in order to get to Sylvan Lake, one of the most popular recreation areas in the Black Hills, in time to get a parking space. Our plan for the day was a hike to the top of Mt. Harney, the highest point in South Dakota—and according to the sign at the top, if you travel east from there, the next time you reach a point as high is in the Pyrenees. You couldn't see quite that far, but the summit does offer an amazing 360 of the Black Hills region, including the back side of Mt. Rushmore. The only downside is that there is a lot of pine beetle mortality in the trees near the top—unfortunately if that keeps up, the Black Hills may eventually look a lot like I had imagined them to be—open and treeless. Harney has an old stone fire tower (CCC era) on top, which the kids really enjoyed exploring, and lots more wonderfully scenic rock outcrops.
After we got back down from Harney, we headed back to Jewel Cave, this time having had the foresight to call in the morning for tickets for an evening tour (from the Harney trail, in fact, thanks to the positive effects of altitude on cell phone reception). Jewel is even longer than Wind—the second longest cave in the world, and very different. It was less tectonically active (perhaps due to its position on the edge of the Black Hills), so it never got the fissures that led to the calcite boxworks in Wind. Instead, large caverns dissolved out of the limestone and then filled with water for a long period of time, and the water became supersaturated with calcite ions which then crystallized over most (ie, about 95%) of the surfaces of the cave - the formations that gave Jewel Cave its name. This cave did have some later water activity, so there are also some draperies, stalactites, cave "bacon" and the like. (We have now been in four caves this trip, and all were really interesting formations: shield formations in Lehman, boxwork in Wind, calcite spar in Jewel, each of which the best known examples, plus a lava tube in Oregon).
Tomorrow we are going to see Mt. Rushmore early in the morning - trying to catch the light and beat the rush—and then head through the Badlands. It is with some melancholy we realized tonight that tomorrow is really our last day of new explorations. After tomorrow we are really on our way home - seeing friends and family along the way, and some sights in Madison and Chicago, but our National Parks adventure really is winding down.