By David S. Whitley

The last two decades have witnessed a dramatic change in the status of North American rock art, expressed in the United States by numerous research advances and a greater concern for conservation and site management. While these improvements are cause for optimism, serious problems persist. Any overview of the current status of U.S. rock art necessarily must consider the tension between newfound success and ongoing challenges.

The United States has a particularly rich record of rock art. For example, there are about fifteen hundred registered sites in California alone, with equivalent or greater numbers in other western states. In part, the wealth of sites results from relatively recent Euro-American colonization, which only occurred in the late nineteenth century in much of the West. In part this abundance also reflects the fact that rock art was an important tradition among most Native American tribes.

	Rock paintings at Horsethief Canyon, Utah. These pictographs, which date to the Archaic period (five thousand to fifteen hundred years ago), are characteristic of the shamanistic rock art that was commonly made by North American hunter-gatherer cultures. Photo: David S. Whitley.

The result is a wide distribution of sites across the entire country, with art dating over a substantial time span. Chronometric dating and other forms of evidence suggest that some of this art was created as early as the Terminal Pleistocene (about ten thousand years ago). The ethnographic record and occasional historical subjects (e.g., European-introduced horses) indicate that its creation continued, in many locations, into the late nineteenth century.

There is also diversity in site type and function. Rock art in the United States includes polychrome and monochrome rock paintings; engravings, incisings, and geoglyphs, in the form of intaglios; and rock alignments.

The ethnography also points to other significant facts, especially for site management. Although the origin and meaning of the art vary regionally, it apparently resulted everywhere from ritual practices—it was a product of shamanistic religions in the hunter-gatherer Far West, for example, and was intended to depict visionary experiences. Depending upon tribe and context, it was made by puberty initiates during group or individual ceremonies, by shamans on solitary vision quests, and/or by nonshaman adults during life crises. In contrast, the pueblo-dwelling Hopi farmers of Arizona engraved personal clan symbols during ritual pilgrimages, illustrating the fact that priestly religions, most commonly found among settled farmers, made rock art unrelated to vision questing.

Regardless of specific origin, contemporary Native Americans have long-standing cultural connections to and interests in these sites. Work at U.S. rock art sites requires juggling contrasting research, management, and conservation agendas, and an accommodation of Native American religious and heritage concerns.

Recent Research Advances

	Petroglyphs from Willow Springs in northern Arizona. These engravings, made by Hopi Indians during ritual pilgrimages, depict the individual clan symbols of the pilgrims. Not all North American rock art is shamanistic in origin. This is especially true of rock art made by farming tribes like the Hopi. Photo: David S. Whitley.

The good news about U.S. rock art research is the numerous recent advances in the field. Since 2000, there have been about a dozen regional and topical summaries, most of which emphasize ethnographic interpretation—the use of anthropological texts and consultations with contemporary tribes—in order to give a Native American voice to the interpretation of the art. Rock art research has also been marked by the development of a series of direct dating techniques. Marvin Rowe at Texas A&M University has led research on the dating of paintings, combining an innovative (and potentially nondestructive) plasma carbon-extraction system with accelerator mass spectrometry (AMS) 14C dating (which accommodates the dating of very small organic samples). His system can potentially date any color pigment containing an organic binder, moving AMS pictograph dating beyond charcoal-based black pigments, to which it was previously restricted.

Ronald Dorn at Arizona State University, Tempe, and Tanzhou Liu at Columbia University have sparked the revolution for the dating of engravings, in the process developing a half dozen independent techniques useful in desert environments. Liu's most significant recent advance involves varnish microlamination (VML) dating. This method is based on the fact that natural rock varnish coatings (the product of hard-fixed airborne dust particles) develop over time in microstratigraphic layers that are themselves influenced by major changes in climate. These layers can be identified in thin section, and once the microstratigraphic sequence for a region is defined and calibrated, it is possible to relate the established sequence to thin sections from archaeological specimens (in a method similar to tree ring dating), in order to bracket the age of the samples. The most recent VML dating breakthrough resulted from Liu's extension of his calibration from the Late Pleistocene and Terminal Pleistocene (before ten thousand years ago) into the Holocene (ten thousand years ago to the present), making it particularly useful for the majority of the North American archaeological record.

Conservation and Site Management

	Aerial view of intaglios. These earth figures, or geoglyphs, located near Blythe, California, were created to commemorate mythic events and actors. Believed to be less than two thousand years old, they were placed at the locations of these mythic events along a ritual pilgrimage route used by Yuman-speaking tribes. Photo: David S. Whitley.

Circumstances have also improved for site conservation and management, despite continuing population growth and urban and suburban expansion. One reason for this positive development is a changing site management paradigm. Until the mid-1990s, site management involved a one-size-fits-all approach predicated on secrecy: if site locations were kept secret, site safety could be ensured. This approach was a failure for a number of reasons, not least of which is that while visitor pressure certainly can be deleterious to rock art, it is not the only important factor in site preservation.

Since the mid-1990s, a substantially more proactive management approach has developed among those responsible for rock art conservation. This approach emphasizes in part the importance of controlled visitation to specific managed sites. An outstanding example is the program created by Peter Pilles for the Coconino National Forest in Arizona. Pilles developed a cooperative agreement with a for-profit tourist concern that includes rock art sites as part of its attractions, requiring that the business fund site conservation and management. Heritage tourism in this case not only promotes site preservation but also emphasizes the importance of rock art to local residents through its significant economic impact on local economies.

	Bighorn sheep petroglyphs from the Coso Range in eastern California. The Coso Range contains roughly one hundred thousand petroglyphs made between ten thousand years ago and the early twentieth century, over half of which depict bighorn sheep—a special spirit helper of rain shamans. These examples are thought to be less than two thousand years old. Photo: David S. Whitley.

A series of recent and ongoing large-scale rock art documentation projects, undertaken in part to preserve the archaeological information contained at the sites, represents a second positive site management and conservation trend. By far the most successful of these is the volunteer effort of the Oregon Archaeological Society (OAS) under the direction of James Keyser, former Pacific Northwest regional archaeologist for the U.S. Forest Service, with the active participation of a number of local Native American tribes. This project has involved the documentation of sites from Alaska to Montana, but the main emphasis has been on The Dalles region in the Columbia River Gorge, which contains one of the largest and most significant (but previously overlooked) concentrations of paintings and engravings on the continent. The work has included the active participation of a rock art conservator, Johannes Loubser, and has explicitly addressed site management and conservation concerns. It has also been conducted following a well-conceived research program that has guided the documentation effort. Although largely staffed by amateur archaeologists, the project has yielded an important series of professional monographs and papers.

Structural Problems and Solutions

Two final issues are important in any assessment of U.S. rock art. The first is the place of rock art in university curricula, because of the implications this has for future research and management. Despite recent advances, North American rock art is effectively no longer taught at American universities. As of 2006, no archaeology PhD program in the United States has a North American rock art specialist on its faculty. In comparison, thirty years ago the various campuses of the University of California employed five archaeologists with American rock art research interests. With the exception of dating research (conducted by scientists in geography and chemistry departments), U.S. rock art research and management are now the almost-exclusive purview of cultural resource management (CRM) archaeologists working outside of the academic system. The difficulty here is that CRM archaeologists are not in a position to train the next generation of U.S. rock art researchers. There is no guarantee—indeed, there is limited likelihood—that there will be a next generation of U.S. rock art researchers to build upon recent advances, given this circumstance.

	Enhanced image of a petroglyph depicting an extinct Ice Age North American llama, from the Rodman Mountains, near Barstow, California. Three independent chronometric techniques date this engraving to approximately eleven thousand years ago, suggesting that the making of rock art extends back to early human occupation of the Americas. Photo: David S. Whitley.

The final issue concerns conservation, per se, and here there is more cause for optimism, despite the fact that not all of our conservation-related problems are solved. First, we have less than a handful of American rock art conservators. Second, we have tens of thousands of rock art sites, but very limited resources for their documentation and management, let alone conservation. Third, because of the vast site inventory, we have no real idea where the most significant conservation and management problems lie. The result is that most conservation projects are after-the-fact efforts—reactive rather than proactive. They represent the least effective use of resources, which would be better spent on preventing problems from developing in the first place.

Fortunately, a partial solution to the last two problems should be implemented soon. Ronald Dorn at Arizona State University and Niccole Cerveny at Mesa Community College, Mesa, Arizona, have created an evaluative system that rapidly determines the relative condition of rock art sites using quickly trained field crews, and integrates the results into a geographic information system (GIS) database. Once implemented, the outcome will be a listing and mapping of sites, ranked in terms of relative degree of peril, primarily from natural processes.

	Microscopic thin section of the rock varnish that naturally coats rock surfaces in deserts, eventually covering the engraved portions of petroglyphs. The alternating layers are the result of major changes in prehistoric climate. The layering sequence for a given region is constant and can be calibrated using rock-varnish-coated geological surfaces of known age. Recent calibration for the last ten thousand years in California's Mojave Desert greatly enhances archaeologists' abilities to date petroglyphs using varnish microlamination dating. Photo: Courtesy of VML Dating Lab.

As geomorphologists, Dorn and Cerveny are interested in rock weathering and its implications for rock art preservation. Their point of departure is the fact that different rock types weather in different but characteristic ways, and this influences site and panel stability and thus the safety of the sites. Their system is accordingly called a Rock Art Stability Index (RASI), and, while it emphasizes the weathering and mechanical stability of rock panels, it can accommodate documentation of other factors, such as vandalism. A trial training and field test, using undergraduate field crews, has demonstrated the practical utility of the index and the replicability of the results. The next goal of these researchers is to integrate RASI into community college curricula, as a response to an increasing demand for interdisciplinary science courses and service-oriented science field projects. The ultimate outcome of these efforts should be the identification of some of our more pressing rock art conservation and management problems, providing us with a better understanding of the sustainability of this portion of our cultural heritage and, from this first result, enhancing our capabilities for managing and conserving sites.

Two decades ago, North American rock art was something of an intellectual unknown. All we had then was a rudimentary understanding of its age and a limited knowledge of its origin and meaning. Although there is still much basic research to be completed, the situation has changed dramatically because of the current and very active generation of rock art researchers. We actually know more about the rock art of some regions today than we do about the remainder of the archaeological record. Documentation and site management have also improved significantly in recent years. Model projects, such as the OAS efforts in The Dalles region, have an important message: successful documentation is a collaborative effort requiring the contributions of research archaeologists, knowledgeable volunteers, conservators, and Native Americans. Our goals, in this sense, should be to preserve, protect, understand, and respect the sites. These aims require an interdisciplinary team effort and approach.

It remains to be seen whether we can successfully tackle the many conservation and management problems that still confront us—if only resulting from the very large number of registered sites. RASI, as a practical approach, certainly will not solve all of the problems that confront U.S. rock art. But it is an important initial step, partly because it will provide our first real measure of what some of those problems actually are. This development alone is cause for optimism, although, as suggested, some steps forward have been matched by partial steps back. We can only hope that the forward progress made in the last two decades will give us momentum to continue to improve the status of rock art into the future.

David S. Whitley has spent over twenty-five years in the field of rock art, working in western North America, southern Africa, and Europe; his most recent books are Introduction to Rock Art Research and Discovering North American Rock Art.