Caballos Novaculite, Near Marathon Basin, Tx

This photo was taken south of Marathon, Tx in far West Texas near Big Bend National Park, I believe on Highway 385.

Here is what wikipedia has to say about it:

Novaculite is a form of chert or flint found in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Upliftof Texas. Novaculite is considered to be highly siliceous sediments and may be a product of the low-grade metamorphismof chert beds. The strata were deposited in the Devonian Period and subjected to uplift and folding during the Ouachita orogeny of the Pennsylvanian/Permian Periods. Novaculite is very resistant to erosion and the layers of novaculite stand out as ridges in the Ouachita Mountains.

This photo took a fairly difficult hike through rugged terrain, made worse by dense thorny vegetation before I could even scale the hill. But once up, the view was incredible.

As it turns out, the Novaculite that is visible from the road is cream colored and fairly unimpressive, but there is a lot of very nice greenish and bluish colored novaculite in smaller amounts, at lower elevation. These nicer minerals have evidently eroded from a non-obvious source, as I did not see the nicer stuff on the hill.

The whole area is very interesting from a geological and mineralogical perspective.