One of Beyer's bat hooks.  This hole had been packed full of sand, camouflaging it. If you look down into the hole, you can even see some remains of that sand-pack. As you can see from the pristine, bare rock surrounding it,  there is no mud flow anywhere nearby.  The only way I could get a sand pack to stick in this hole like I found it was to make a paste of spit and dirt and then use my fingertip to work that paste into the hole. After a few minutes, this paste dried, and the hole virtually disappeared. By mixing different colors of dirt, it is possible to artistically color-match the surrounding rock, and the hole can be made invisible. Beyer WAS an artist, although not in the traditional sense of the word when used to signify route creation.  At least, after a few holes like this one, we knew what to look for.