By rubbing a spear head against stone to form or sharpen it, a groove is gouged very similar to the grooves beside the Procession Panel

Comb Ridge is a monocline spanning between southeastern Utah and northeastern Arizona—a formation 80 miles long with a north-south orientation, rising gradually on the eastern side and dropping precipitously 600 feet on the western side. It is an immense and magnificent structure and it has truly ancient Native American history, including the discovery of an intact Clovis Point spearhead and a petroglyph of a mammoth—both of which date to 13,000 years ago. 

In addition, it is home to Ancestral Puebloan dwellings that were occupied from 1150 to about 1290 AD. In 1990, teachers discovered a large petroglyph panel at Comb Ridge that is now called the Procession Panel. Near the Procession Panel, I found something that I did not understand. 

Monarch Cave is an Ancestral Puebloan dwelling in a large alcove at the end of a canyon, beside an intermittent waterfall and high above a splash pool. The structures have some intact walls, and the cooking area is littered with small corn cobs. Several metate depressions were formed in the floor by grinding corn with a small rock called a mano. The ceiling is darkened with the smoke of cooking fires and a nearby wall is stained with the activity of tanning leather. 

The two approaches to the alcove are very narrow, so the site was easily defended. Monarch Cave was occupied from 1150 to 1290 AD, when most of the people in the Four Corners area abandoned their ancestral homeland due to drought and famine. 

The Procession Panel, above Monarch Cave and farther west, decorates a vertical red rock wall that catches sunlight late in the day. It is 15 feet long, and it depicts 179 people coming from three directions to converge at a kiva, a meeting place with spiritual significance. 

Two of the people wear bird headdresses, and several others are carrying hooked staffs, indicating that they are chiefs. Animals include bighorn sheep, deer, snakes and either wolves or dogs also are depicted. Hunting activity is represented by atlatls (slings to hurl spears), and two animals depicted in the panel are impaled by spears.   

When I was at the Procession Panel, I looked around for other petroglyphs. Approximately 70 feet north of the panel I found two vertical grooves in the rock. They were about one foot long, about three-eights inch wide and one-half inch deep and in cross section were V-shaped. They did not look like art, but they appeared to be purposely formed. I looked up, then down, but they did not point to anything unusual. I did not know what these were.

It turns out that many Native American sites have grooves gouged into rock. The Cape Cod National Seashore in Massachusetts has a display near Nauset Marsh of a 20-ton communal sharpening stone called Indian Rock. It commemorates thousands of years of activity of the Nauset people, who used the rock to sharpen spear points, harpoons and fishhooks. 

A similar display in Chatham, Massachusetts, recognizes the long history of the Monomoyick people with one of their sharpening stones. And for thousands of years, Native American people from at least 15 tribes in the northwest traveled to Kettle Falls on the Columbia River between Oregon and Washington to harvest salmon leaping up the falls. 

All who came to catch fish were invited to sharpen their spear heads on the sharpening rock, a boulder weighing one ton that is now on display on the bank above the river, commemorating the times when the river ran free and Native American people lined its banks harvesting salmon. Here in Colorado, sharpening grooves are prominent at Balcony House in Mesa Verde National Park. 

Archeologists have described and demonstrated the efficacy of abrasion for sharpening stone spear heads, bone awls or needles. By rubbing a spear head against stone to form or sharpen it, a groove is gouged very similar to the grooves beside the Procession Panel. Experiments with sharpening spear points produce grooves that are straight, V-shaped in cross section and shallower at the ends, like those at the Procession Panel. 

However, Native American people used many implements, from large, heavy cutting tools wielded with two hands to butcher bison to axes for cutting trees to small knives for preparing food. For each of these, the shape of the groove differs because the shape and size of the tool differed. Sharpening grooves are seen at many Native American sites and on other continents. 

The Procession Panel shows atlatls, but not bows and arrows. The rock art panel was dated to 760 to 800 AD, about the time (800 AD) that bows and arrows replaced atlatls.

Once I began a literature search on grooves in stone at Native American sites, I was humbled by my realization that I had been ignorant of something that was common here in the West and known around the world. 

But I got over that and remembered the exhilaration of visiting a place where the landscape so strikingly beautiful and imagining how life was for those who lived in Monarch Cave 800 years ago and fed themselves with what they could glean from their immediate surroundings. A visit to Comb Ridge is profoundly moving.

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