The white rock in the roadcuts around here is chalk — the compacted remains of microscopic algae that settled on the floor of a shallow sea about 85 million years ago, the same kind of deposit as the cliffs at Dover. It is soft enough to cut with a hand saw, which is why so many 19th-century Central Texas buildings are made of it, and it is naturally fractured, which is why the Giddings field pulled hundreds of millions of barrels out of it starting in the 1970s. The chalk band runs from Del Rio to the Red River, tracing the Balcones fault line the whole way.
Getting there
30.1830, -96.9360
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.
