Natural Bridge Caverns (near San Antonio, TX) – May 2007

DESCENT INTO THE DEPTHS OF THE EARTH … UM, TEXAS

I like caves.  I haven’t been one to get on my hands and knees and shovel through the mud to explore caves.  I much prefer ones I can go walking in.  Makes for a good day outing.  Back in New York, the only caves I got to explore were the “iron mines” near Camp Wakpominee (in Fort Ann), or Howe Caverns (near Schoharie).  Both of those are what are considered “dead” caverns, as they’ve been open to the outside for so long, people and animals have stopped the caves from “growing.”  I know this from a visit to Inner Space Caverns (in Georgetown, TX) in early 2003.  I don’t have any scanned in shots of that trip (nor the second time I went in 2005), but I do for my visit there in 2010.  You’ll see those soon enough.

Cara, my friend from SUNY Plattsburgh, was going to be in San Antonio for a geology conference.  Since that’s only an hour away from Austin, we made plans to hang out on the Saturday once the conference was over.  I drove down to San Antonio picked her up, and headed back northward to what looked like a fun destination:  Natural Bridge Caverns.

Natural Bridge Caverns is only about thirty minutes north of San Antonio (and slightly west of New Braunfels), so it was close by.  One thing I’d learned earlier was that Interstate 35 pretty much sits above a fault-line where two geologic plates come together.  East of IH-35 things are pretty flat, and west of that is the “hill country.”  Not too many earthquakes happen here, but they can happen.

I will say this, pictures do not do these caves justice.  Ignore the fact that I was a moron and didn’t have the “anti-shake” feature on, so most of my shots turned out shitty.  I guess I have a reason to go back again.

IT’S CALLED THIS WHY?

Commercial caves, the ones that make their money from tourism, always need to have some catchy name for people to remember them by.  Right at the very beginning of the tour we learned the reason why.  The whole area was a nice field that people went about their business until one day the ground gave way.  This collapse revealed the caves underneath.  These caves had at one point been open to the outside, and housed a bat colony, but had since been closed up through geologic action.

The way the collapse happened, it left a section of rock over the exposed portion which resembled a bridge.  Viola!  As our guide showed up, the rock was at least a foot thick in a few locations (and a bit more than that in the rest).  They’d really not have anyone go out across it, because sooner or later it would come down.  They equated it to thin ice.  One or two people may go across it quickly, but it’s not recommended.

Under the bridge are the steps which bring you down into the cave.  There’s a glass door which has been installed in order to keep the proper humidity in the cave, so it stays “alive.”  A “living” cave is one where the rock formations are still growing.  Oil from the human skin, and other animal interference, will strip away the surface of the rock so the formations won’t grow any more.  There’s more of a scientific explanation behind it that the guide tells.

INSIDE THE CAVES

Walking these caves is not easy.  Even though there’s a pathway constructed so you stay confined to specific areas, and handrails to you’re your balance with, the area is slippery.  Water (filled with minerals) constantly drips from the ceiling.  Those are called “cave kisses.”  They also make the floor wet.  Once we passed through the entrance door, we had to go down a series of switchbacks that brought us down a few hundred feet to the main section of the caves.

Once there you see various formations that were created by a geologic process lasting thousands of years.  The stalactites which hang from the ceiling will eventually meet the stalagmites on the floor, and form the columns.  Each of the columns, or a specific section of columns have there own names based on what they look like.  This is akin to seeing shapes in the clouds, but it’s very abstract.

 As we moved across the pathway, we noted there were few lights in the area.  Sure it made things a little dark and murky, but it also helped preserve the caves.  The tour guide would point out specific points with his flash light.  The trail splits into two sections, a “high road” and a “low road.”  Since there had been so much rain recently, we couldn’t take the “low road,” as the lower sections of the caverns were flooded.  The “high road” is essentially a bridge over a large cavern pool.  If the rains had blocked any portions of the “high road” then the entire caves would’ve been closed until the water receded.

The last major portion of the room we come to is the size of a large auditorium.  That’s where there’s a winding path which will bring us back up to the surface, but its easier going than the entrance path (not a continuous series of switchbacks).

The path goes around what you think it just another rock formation, just one that’s a darker material than others.  Then you realize it’s a pile of bat guano … a couple hundred feet thick.  On the ceiling of the area is a blackened section, which almost looks like the rock was burned.  That’s what the tiny claws of millions of bats over thousands of years had done to the ceiling.  That section will not grow any more formation.

  

After passing the giant pile of bat shit, a small corridor brought us the exit, and other glass door designed to keep in the moisture and the cave at a constant temperature.  A garden path takes you on a nice nature walk before bringing you back to the starting location.  The rest of our day together was taking a boat ride on the San Antonio Riverwalk, a casual dinner, and a lot of talking by friends who hadn’t gotten to see each other in years.

More information can be found at http://www.naturalbridgecaverns.com

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