Reading the Rocks

The Geology of Paintrock Canyon

By Alice Wilkinson

December 4, 2024

A blur of sagebrush, slashes of sandstone, chunks of granite, stripes of blue: a visit to the Paintrock Canyon Ranch is like stepping inside a watercolor painting. These colors, layered one atop the other, paint a vivid scene of a landscape defined by sharp contrasts. Soft grasses and sagebrush are quickly swallowed by limestone cliffs and canyon walls. This unique geology is characteristic of northern Wyoming, where the 80,000-acre Paintrock Canyon Ranch sits. Nestled along the southern rim of the Bighorn Basin, the property rises up to meet the western edge of the Bighorn Mountains. The basin, which is shaped like an oval bowl, has been studied for centuries by archeologists and scientists because it is home to some of the oldest sedimentary rocks on the planet. Depending on the diameter, thickness, color, and texture of these rocks, scientists have tracked the movement of continents, natural disasters, and animal evolution. To read these rocks is to travel back in time, imagining the landscapes that existed millions of years ago.

The ranch’s acreage contains most of this history: the canyon walls that surround the Paintrock Creek are made of limestone that dates back to the Precambrian Age (550 million years ago) and the bright red hills that surround ranch headquarters date back to the Triassic Age (220 million years ago). Between these two periods oceans and swamps dried into deserts and mud flats, home to everything from algae and insects to antelope and dinosaurs. As time went on, these landscapes were slowly buried underground. It was only about 45 million years ago (for some unknown yet miraculous reason) that the layers of rock, many of which contained fossils of ancient plant and animal life, began to rise up. They pushed past the earth’s surface and created the Bighorns and Absarokas, while rivers sliced through the mountain ranges and exposed the buried rock. The best way to get a sense of this and feel the juxtaposition of scale and color is to explore the country horseback.

Beginning at ranch headquarters, you ride north, past the irrigated pastures and cottonwood groves. Flat fields of green quickly blend into a series of red hills. At the base of these red hills, which dot the eastern and western edges of the ranch, are outcroppings of sandstone. If you look closely at the cross-bed of the rock, you see rows of slanted lines, mimicking the shape of waves. These wave patterns are buried sand dunes from the Pennsylvanian Age, 330 million years ago. 

As you head back into the canyon, the air cools and the palette darkens. Heaps of grey and black rock appear, sharp and imposing formations from the upper Ordovician, roughly 450 million years ago. A quick change from the soft hills surrounding headquarters, these towering cliffs look like the wings of an ancient eagle. They are part of a formation called the Bighorn Dolomite. Made of limestone and sandstone, they envelope you on both sides as you ride among smaller scattered rocks and sagebrush. The Paint Rock Creek rushes alongside, filling this winged tunnel with slow and steady music.

Continuing to gain in elevation, you traverse sections of the Meeteetse Formation. Similar in appearance to the Bighorn Dolomite, this rock is more grey and white in color. Flowering plants and grasses are scattered across it. In some sections, there is fossilized vegetation – grasses that dinosaurs grazed – from roughly 70 million years ago. The Meeteetse also intersects with the Badlands, thick sections of rock washed in cream and clay stripes. Embedded within these Badlands are a range of fossils, containing some of the earliest bones of ancient horses and antelope.

The ranch’s boundaries eventually extend into the Bighorn National Forest, so after miles of muted color, the journey ends in lush alpine meadows that seem to touch the clouds. During the summer months, our cattle graze in these meadows. We also lead pack trips into this wilderness area and explore the range of peaks, including Cloud Peak, the highest point in the Bighorns. Ranchlands has a grazing lease with the Bureau of Land Management that allows for this seasonal movement.

To explore this section of Wyoming is to delight in its contradictions: red clay hills anchored by sandstone, wildflowers sprouting out of black rock. These observations create a shared history that can only be found in stillness. As you ride through these distinct layers, you begin to picture the animals – antelope, horses, dinosaurs – and the landscapes – oceans, deserts, forests – that once existed. The parallels between the years appear like brush strokes in the mind, vivid yet fleeting.

MORE FROM THE RANCHLANDS REVIEW

Cart

No more products available for purchase

Your cart is currently empty.

Donate to the Ranchlands Collective

Would you like to support our 501(c)(3) and its mission to connect people to the land through education and conservation?
Donors receive free shipping on orders from the Mercantile.

Other