You can see the varves in the Castile Formation in a roadcut along Highway 180, about 12 miles south of the Caverns. The "State-Line Outcrop" is a famous stopping place for geologists, where, exposed to view, are thousands of varves, thosands of years of climatic history.
Our part in the Castile story was to count and measure
each millimeter-layer, year by year, bottom to top, and put together the
world's longest annual record of climate change. Our search began at the
State-Line Outcrop and our first visit introduced us to an intriguing mystery.
State-Line Outcrop, looking southwest. In the far background is Capitan
reef. The NM/Texas state line is at the fenceline and change in vegetation
in the middle distance.