Adam Wilson’s Cave Map

I created an award-winning map for Adam Wilson’s Cave (a.k.a. Bonnie Hills Cave), winning Best of Show at the 2020 Texas Speleological Association Convention. This is my first cave map, and due to the massive amount of work that I now realize drafting cave maps entails, it will likely be my only cave map. I will now retire undefeated. 😀

For those of you who don’t know Adam Wilson’s Cave, it is immediately impressive. It begins with a collapsed dome entrance that descends into a massive room about 200 feet (60 meters) wide. The slope into the collapsed dome is huge breakdown, and the room wraps around the breakdown out-of-sight on both sides. The cave itself consists of four distinct sections: the Collapsed Dome Entrance, Ray’s Bone Maze, the Confusion Tubes, and the Lower Levels.

The cave is also home to a large, migratory bat population. The bats primarily reside in the entrance of the Confusion Tubes and in the first major room in the Lower Levels (dubbed the Bat Room). The huge bat population allowed me to capture my best bat photos to date, several of which I included on the map.

An interesting note is that Adam Wilson’s Cave is unusually cold. Cave temperatures are typically the average yearly temperature for the region. In Texas, that means caves are usually 76–78°F (24–25°C) for the entire year. However, Adam Wilson’s Cave and another Texas cave, Punkin Cave near Del Rio, both have an unprecedented temperature of 47–48°F (8–9°C). No one is exactly sure why, but I have a theory. Both caves have a large sinkhole entrance and maze-like lower passages. The large sinkhole acts as a cold-air sink. In the winter, the denser cold air slowly settles into the lower passages and forces the warmer air out. During the summer, the complex lower passages restrict warm air flowing inward during brief high-pressure fronts. Over time, the bedrock itself cools, which compounds the effect of forcing warmer air out.

Despite being my first (and only) cave map, I think I did an amazing job. Obviously I did something right since it won Best of Show. However, what I am particularly proud of is the colored shading. This is a new technique that I invented while making this map. I have combined the new trend of shading exterior walls with the old technique of color-filling passages to indicate different levels. This has several advantages over the old color-fill method:

  • Shading helps define overlapping passages.
  • Interior passage details are visible, in contrast to the solid color of color-filled passages.
  • Still prints nicely as black and white; colors translate to gray shading, in contrast to the dark swaths of old-style color-filled passages.
  • Looks mighty fine (IMHO).

Let me know what you think in the comments below.


Update: Although I stated above that my Adam Wilson’s Cave map was my first and only cave map, I forgot that many years ago I “drafted” a map of Cricket Crap Cave from memory. I have included it in the entertaining trip report, along with photos featuring Gary Donham’s glistening naked torso. You definitely want to check out that eye candy.
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