GEOLOGY HAPPENINGS - January 2026

A rock layer (a formation to geologists) is package of sediments that were deposited at some point in the geologic past, then buried by additional sediments and turned into stone by pressure, the addition of minerals that act as cements, and other geologic changes during the process known as diagenesis.

Geologists study the rock layers in a given area like Moab to understand its geologic history and the evolution of its modern landscapes. The science of geology concerns itself with the history of Earth and the processes that shape the planet. Rock layers, are, in short, the historical record of the geologic past.

For example, the rock layers exposed in southeastern Utah tell the stories of inland seas that covered this area during some periods of geologic history and of the massive fields of sand dunes that were here at different times.

Although geologists are mostly interested in studying rock layers for scientific reasons, the general public largely appreciates their aesthetics (although geologists also certainly appreciate their beauty). Bedrock is quite literally the building blocks of landscapes, and here in canyon country, the dry climate and rapid rate of erosion means that exposures of the rock layers are the dominant aspect of the scenery. The Moab area is fortunate to have exceptionally beautiful rock layers. The presence of these scenic rock layers is the main reason why southeastern Utah contains two national parks, four national monuments, three state parks, plus other public lands known for their inspirational qualities.

The beauty of a rock layer is, of course, subjective. But even so, several rock layers found in the Moab area have exceptional aesthetic qualities and have outsized roles in the creation of the beauty of the canyon country landscape. I have ranked the layers that I personally find prettiest in southeastern Utah and that form some of my favorite scenic spots.

#5: Cutler Group
The Cutler Group is the reddest of all red rocks in canyon country with a dark red to a rich purplish maroon color. These red beds were eroded from the ancestral Rocky Mountains that existed in southwest Colorado about 300 million years ago and carried to southeastern Utah by rivers. The red color comes from the weathering of mineral grains and the presence of clay minerals.

The Cutler Group is most prominent north of Moab at Fisher Towers, a popular hiking area near the Colorado River. Some Cutler outcrops are along Highway 191 northwest of Moab and are recognizable by their almost purple hue and rounded knobs.

#4: Cedar Mesa Sandstone
The Cedar Mesa Sandstone is present in the Needles District of Canyonlands National Park and further south in the eponymous Cedar Mesa area, including at Natural Bridges National Monument. A massive eolian (deposited by wind in dunes) sandstone, the Cedar Mesa ranges from orangish red to off white in color. In the Needles District, this sandstone is usually banded in those colors. Natural Bridges National Monument contains the three large natural bridges, but also beautiful canyon walls, all sculpted from the Cedar Mesa Sandstone.

#3: Navajo Sandstone
If the rock layers exposed in the entire state of Utah were ranked for their scenic qualities (versus just here in its southeastern corner), the Navajo Sandstone would unquestionably be the state’s geologic beauty queen. The Navajo Sandstone makes up the canyon walls in Zion National Park and Glen Canyon, and the white domes of Capitol Reef National Park.

It is a less prominent layer near Moab, but it found in the Petrified Dunes in Arches National Park, as well as at Mesa Arch in Canyonlands, and Corona Arch. It is usually off white to light yellow in color, but may have a reddish hue, especially in Zion. Like the Cedar Mesa Sandstone, the Navajo was deposited in ancient sand dunes.

#2: Wingate Sandstone
It would seem fitting for the Wingate Sandstone to be described as handsome versus beautiful because it most often forms tall, angular cliffs that tower above the surrounding landscape. Together with the Kayenta Formation above it, the Wingate also tops most of the mesas, buttes, and spires found in the area. Simply put, canyon country would not be canyon country without the Wingate Sandstone. Usually a pleasing brick red color, the Wingate Sandstone is perhaps the most iconic rock layer in southeastern Utah.

#1: Entrada Sandstone
For its beautiful orange-red color, rounded rock domes with graceful lines, and the host of natural arches and windows found within it, the Entrada Sandstone is the winner of this red rock beauty contest. The Entrada Sandstone is almost single-handedly responsible for there being an Arches National Park. Most outcrops of the Entrada in southeastern Utah are within park boundaries, and given the 1.5 million people who visit Arches each year, it is likely that many people agree with the Entrada being the fairest of them all.

A self-described “rock nerd,” Allyson Mathis is a geologist, informal geoscience educator and science writer living in Moab.
To learn more about Moab’s geology, visit the Geology Happenings archive online at https://www.moabhappenings.com/Archives/000archiveindex.htm#geology