|Enchanted Rock is a granite dome occurring in the
Enchanted Rock State Natural Area,
a state park located in central Texas.
Located on the southeast margin of the large Enchanted Rock Batholith, the granite exposed is one of the Town Mountain Granite suite and is of Precambrian age. U-Pb zircon geochronology gives an age of 1082+-6 million years old (Walker, 1992) which corresponds to the late Proterozoic subdivision of the Precambrian. Precambrian rocks in central Texas are part of the Llano Uplift.
From Llano, Texas-- drive south on Rte. 16 around 22 km (13 miles) to Ranch Road 965 (on the right, just after you cross Sandy Creek). Turn right and it's about 13 km (8 miles) further to the park.
From Fredericksburg, Texas-- drive north on Ranch Road 965. It's a ways, about 30 km (18 miles), but worth the trip. Very scenic route and some day I hope to drive it in a Porsche.
A detailed road log, starting in Fredericksburg, going to the Park, and continuing on to the town of Burnet, is available for download.
Other web sites discussing Enchanted Rock.
Sources of detailed geologic information on ERSNA and the Enchanted Rock Batholith.
What's this "second largest" thing??
The organization you should thank for the ERSNA being there.