Mom's been threatening to go to Cave of the Mounds for the past 10(!) years, but only today (well okay it's after midnight, yesterday) she gave in seemingly on impulse and we (me, Doug and her) went. Here's some photos I snapped, enjoy!
Cave of the Mounds is between Blue Mounds and Mt. Horeb, WI.
This is the gift shop, with Mom standing in front of the main doorway (the other is to the right, hidden by the wall). The entrance and exit to the cave are inside. Before you enter, they show a short video on cave formation, geology, etc. It's also a dark show, so it gives your eyes time to adjust to the darkness - the cave is pitch black, and they use lights sparingly throughout the tour. I'll warn you it didn't make for easy photography, and our cheezy digital camera doesn't help much either. :-/
This is the view right after the stairs (from the video room). The first thing you notice about this cave is it's cold - about 50°F, so bring your jacket - and it smells a little musty (to be expected). I thought it smelled like a basement, only not quite so organically musty, and a little spicy(?).
I think this is a closeup of the above picture; if not, it's farther down. In any case, this is another stalagmite, covered in flowstone - so called because it seems to flow in a slow molten state over the formation - but in reality it's hard, solid calcite (with a little iron or manganese impurities thrown in to give it the yellow, red, orange, blue or black color). These formations are at least 6' above your head, so a good 12' tall off the floor. The ceiling is about 15 or 20' tall, and 30' thick limestone above there (or was 30' how deep we were? I forget).
Farther down (the prev. pic is at the north end of the cave, the path loops back going under the concrete floor you were just on), the cave turns from carbonic acid (CO2 dissolved in water) dissolving the limestone and depositing stalactites, to an underground stream especially rich (on a geological scale, that is) in sulfuric acid, picked up from weathering sulfide deposits such as galena, pyrite and so forth. This, combined with the water current (again, probably fast only on a geological scale) wore away the lower limestone much faster, and gives the lower cave a winding path. This photo is of just one of several such cavities eroded by the water; for the next couple of minutes you get to walk through the meanders themselves (where the water flowed).
The tour guide described this as: water drips in from the "life line" (the original crack which formed in the limestone which allowed the water to percolate through and erode the cave) into a pool at the top of this photo; it builds up and every so often, spills over, and each time it does it deposits more flowstone down the slope.
Mom and me posing for a shot (Doug holding the camera) in front of an outcrop of soda straws (stalactites named for their being completely hollow inside). A nice area.
After the previous area, looking back. Two pools either side of the path, with soda straws and other stalacti above.
I can't remember exactly where this is... In any case, more stalactites and a few stalagmites.
Another long stalactite with a nub of a stalagmite forming below it. They say it takes a hundred years for these things to grow about a half an inch (depending)...
Me screwing around with a mirror in the gift shop. :-p Hey, it wasn't my idea, ask Mom! ;)
Well, tour's over, hope you had fun! I did!