Thirteen miles of county road run through private ranchland, and the arrangement is older and more deliberate than the traffic suggests. That part of Gillespie County had no public roads at all until 1934, when the Commissioners Court established a third class road forty feet wide from the Holmes-Moss Ranch across to the Llano and Fredericksburg road. Those forty feet are the whole of what is public. The land on both sides belongs to somebody, it is posted, and the wildflowers are on the far side of the property line. Paving began in the 1960s with material donated by the rancher A. F. Buie, who owned the Serpentine Mine on the loop, and the commissioners finished the job in 1976. The mine is a clue to what the road reaches.
At the loop's northeastern end, four miles of the Coal Creek Serpentinite run beneath it, up to a mile and a half wide and cut by thin metabasaltic dikes. It is a fragment of oceanic crust, sheared into place against the Big Branch Gneiss and the Packsaddle Schist when an island arc collided with North America about 1,150 million years ago, and the rock has been quarried for flooring. Reaching an outcrop of it means asking a landowner first.
The valley the loop drops through is different rock entirely: coarse pink Town Mountain granite, the same mass that forms Enchanted Rock twelve miles west, strewn into boulders. One account of the road calls that stretch Hell's Half Acre. Further north the loop crosses ground where Paleozoic sandstone sits directly against the granite, not along a quiet unconformity but along normal and oblique-slip faults thrown up by the Ouachita Orogeny, hundreds of millions of years after the granite cooled.
Getting there
30.4538, -98.6469
Locations are approximate and may be inaccurate, on private land, or otherwise inaccessible. Check before you travel.
Hear it from the road
Whistlestop tells you this story automatically when you drive past. No searching, no tapping, nothing to ask.
