Thursday morning I set off for Madison Ruby Conf. The conference didn’t start until Friday, so I figured I could look around a little. When I went to look up madison attractions however, the only one that really struck me was The Cave of the Mounds, a little outside of the city proper. (The House on the Rock was farther out, and a day trip in and of itself.)
It turned out to be around a half-hour past Madison, so it wasn’t quite as quick of an excursion as I thought. I did pass Erb Road on the way out, which seemed somehow appropriate for a trip to a Ruby conference (ERB is a common template format in Ruby on Rails) I relied on there being signs to direct me to the cave, and was not disappointed. I suppose it was about as close to the highway as a natural landmark could reasonably be.
Once I got out of the car, I saw a sign saying that the caves were cool, so I went back for jeans. By good fortune I was already wearing my only regular long-sleeve shirt, from Rubyconf.
The area outside of the cave includes a road painted as a timeline, terminating at the front door of the waiting room/gift shop, with the date of discovery. The gift shop was exactly what you’d expect – lots of fossils and crystals. It looks like they have recently installed a fossil dig and gem mining (e.g. rinsing)
The tour itself started with a video which went over the formation of caves and the discovery of this cave. The cave itself is an interesting study in contrasts. One one hand, they admonished us not to touch the cave, since it can disrupt the natural cave formation. On the other hand, the floor has been paved with cement to create a smooth walking surface, with stairs in places. The larger portion also has at least one artificial level, which obscures the size of the main cavern.
It’s also a study in the contrast of light and dark. The cave itself has no light at all (a point demonstrated for a few moments in a “you can’t see your hand in front of your face” part of the tour. (The little girl with flashing shoes thankfully remained still.) Lights are turned on selectively as tours pass through, with the stated purpose to prevent mold and such from finding it too hospitable. Lighting is mostly spotlights, pointing out salient cave features while maintaining the suggestion of darkness. The tour also uses the light to great effect, leaving areas in darkness until it suddenly opens up in a dramatic reveal.
One feature of the cave is where deposits formed variegated strips called “cave bacon”. Apparently water drips follow a path and leave behind deposits; this makes the area slightly lower, and more drop follow, slowly building a ridge. It was another apropos point for the trip to Madison Ruby (Chunky Bacon is a part of the Ruby culture)
Towards the beginning of the tour, we were shown an area where a sinkhole had collapsed into one end of the cave. I spent a little time afterwards going around the above-ground paths. I found a few sinkholes, but it wasn’t clear which one was over that end of the cave.