Cyndi,
The soil isnt that compacted that these things don't eventually fall down,
there are even Spanish signs that sit up on these things.
I think the Spanish took advantage of some of the geological features in this area and made quite a spectacle of the trails they used here. there is a mule trail that goes over the top of this hill and it has some very interesting signs due to this weather feature.
Unfortunatly these photos aren't mine so I must wait a bit to get permission to show them.
Ted may want to wait a while as he is using them right now.
Thom