Castle Rock butte is a mountain that has withstood the erosional forces due to its "cap" of castle rock conglomorate.  It "cap" consists of various age depositions of rhyolite, granite, and sandstone.  The rhyolite is from an ancient volcano that erupted near Mt. Princeton about 36.7 million years ago.  As described in the page Daniel's Park, this layer of lava flow was once flat (see bottom of that page).i

GPS Coordinates:
N 39^o 22.740'
W 104^o 51.386'
Elev: 6510 ft

Castle Rock conglomorate showing purple rhyolite blocks in smaller
granite cobbles and sandstone.
 

REMAINDER STILL UNDER CONSTRUCTION