Missouri doesn't have rocks quite that old, but the Ozark Mountains are still downright ancient. Our own St. Francois Mountains date to over 1.4 billion years ago, making them much older than the Appalachians (460 million years) and the Rockies (70 million years).

One of the best places to see really, really, really old rocks is at the summit of Hughes Mountain in Washington County, southeast of Potosi.

During the climb to the top, the bald summit doesn't look that special:

But this mountain is unique in Missouri and possibly the entire Midwest. It has columnar-jointed rocks that form vertical pillars with sharp edges. While not very tall, these columns are shaped into hexagons and other geometric shapes, sort of like a honeycomb. In fact, this place is nicknamed the Devil's Honeycomb:

The Devil sure gets around: similar, but much larger, examples of columnar-jointed rocks are found at Devil's Tower in Wyoming and Devil's Postpile in California.

These rocks formed when lava slowly cooled and joints were created at crazy angles, allowing the rock to weather away over time into the pillars.

Devil's Honeycomb isn't confined to just one outcrop, but covers a large part of the sprawling Hughes Mountain summit.

With a peak of 1,210 feet, Hughes Mountain is nowhere near as tall as Missouri's highest point, Taum Sauk Mountain at 1,772 feet. But the summit of Taum Sauk is flat -- it's really more of a ridge -- and the view from the peak is limited. Hughes Mountain dwarfs the surrounding terrain in all directions, offering a panoramic view:

To the south, the next major peak is Buford Mountain (the bumps in the distance) at 1,740 feet.

The hike to the top is a strenuous, but thankfully short, half-mile climb. You'll want to take plenty of time to fully explore the 1.4 billion year old rocks and to enjoy the view of other ancient mountains in the distance.

Driving directions

From Cape Girardeau, take Highway 72 west through Jackson, Patton, Fredericktown and on to Arcadia. Then take Highway 21 north through Pilot Knob, Belleview, and Caledonia. A couple miles past Caledonia, turn right on Route M. After 3.4 miles, look for the turnoff on the right for Cedar Creek Road. The parking area for Hughes Mountain Natural Area will be on the left a short distance down this road. [Google map]

You can also take I-55 north to the Ste. Genevieve exit and then follow Highway 32 west through Farmington, Park Hills, Bismarck, and on to Caledonia. There's a shortcut from Highway 32 by taking Cedar Creek Road before reaching Caledonia, but that involves crossing a deep creek on a tricky low-water bridge.

Quick facts

Name: Hughes Mountain

What: Ancient peak with unique columnar-jointed rock

Owner: Missouri Department of Conservation

Designation: State Natural Area (430 acres)

Topographic map: Irondale

GPS coordinates: 37.8019939, -90.7098499

Links: All Outdoors newsletter; Missouri Natural Areas