OOC # 19
Cavernlands? Or Canyonlands? I've never heard of the former. The latter is...oh...three and a half hours or so south of where I'm at. If you look at a map of Utah, I live on the strip of land east of the Great Salt Lake, before you actually get up into the mountains.
Sounds like you're describing Delicate Arch...it's not an actual cavern, it's a naturally occurring stone archway, eroded by wind (probably started by water, once upon a time, but it's high enough above the current water table that it hasn't seen more than rainwater in centuries.) South-eastern Utah has a whole series of national parks (collectively known as 'Canyonlands') that are full of unusual stone formations left over from various erosion processes.