Cavern 46

 Cavern 46

One passage in from the left. One passage out from the right. The leftmost enters a small room, then more passage into a larger chamber or a turn into a small chamber/passage. From the right all the way down is a room, and adjacent a large chamber, but instead if one turns, you enter a passage that is a small loop connected to the largest chamber in this cave. It is 361 feet of vertical drop.

Here is a alien stone/unusual stone formation version.

Less space for movement, but a passage could be added, and there is more space for bugs and animals and bones and coins and water and fungi and algae and bats and everything else that could be in crevices in the cold stone.