The petroglyph designs found in the Owyhee uplands are similar to those from the Columbia Plateau, Idaho and the Great Basin. Petroglyph designs were influenced by populations on all sides. This suggests that people were not moving in only one direction across the Owyhee uplands. It is likely that if the petroglyph sites in Harney County to the west were examined, there would be similarities with the spectrum of designs. Pitted elements for example are found in northern Nevada, the Owyhee uplands and the Columbia Plateau.
It is probable that the rock walls and rock circles were used in hunting. Modern pronghorn hunters who go out to Dry Creek (in the Owyhee uplands) locate a water hole along the creek and wait downwind from four in the morning until antelope show up. Some of the circles are located almost exactly at the rim (35ML1050, 35ML1052, 35ML842), locations which would be good for watching the area below without being observed. Some of the rock walls cut off possible escape routes along confined paths; if a pronghorn (Antilocapra americana) were spooked it could be funneled one direction (35ML850, 35ML1046, 35ML1050). Pronghorn, unlike deer, do not jump over fences unless forced to do so; today they are more often seen searching for breaks in barbed wire fences (Lubinski 2000).
The construction of rock walls at 35ML850 to act as a funnel could have aided in hunting pronghorn. Pronghorn moving up the draw from the creek are constrained by tall rim rock on the left and the right side is blocked by the wall (Figure 13). Since pronghorn do not often jump vertically, they would be hesitant to jump a manmade rock wall. As the wall became a permanent feature of the landscape, pronghorn would be accustomed to using the path they had been funneled into; a hunter could wait patiently in the rock circle for a pronghorn and probably get a better aim and closer shot.
1Petroglyph sites in the Owyhee uplands can be compared to the archaeological sites. Artifacts found at petroglyph sites are lithic scatters, lithic tools, rock features, ground stone, rock shelters, shell fragments and bone fragments. Ceramics, pit houses and woven materials have not been found at petroglyph sites. Lithic scatters are found at 64% of petroglyph sites and 94% of all archaeological sites. Two types of petroglyph sites mostly lack lithic scatters: the water tub sites and riverside sites. At water tub sites, lithics are not present because the sites were not used for long periods of time. To the contrary, riverside sites were probably habitation sites which would have lithic scatters, but the site extent has not yet been explored. Lithic scatters could also be scoured from riverside sites by highly variable water flows.
Rock features are found at 36% of petroglyph sites and only 5% of all archaeological sites. However, petroglyph sites are differentially associated with rock features; 9 of 11 mesa top sites are associated with rock features while none of the riverside or water tub petroglyph sites have rock features. In another comparison, 84% of petroglyph sites are within 1500 meters of a perennial water source while only 72% of all archaeological sites are this close to perennial water. This high percentage for petroglyph sites relates to the use of both riverside and mesa top petroglyph sites as campsites and locations where resources could be collected.
Petroglyph sites in the Owyhee uplands are part of the settlement system. While the settlement system is not well understood, petroglyph sites occur in areas where there are both high and low settlement densities. The most striking example comes from the Owyhee River. Along the Owyhee River where the density of archaeological sites is high, petroglyph sites are also frequently found. On the mesa top, settlement density is low, but petroglyph sites are still to be found. However, petroglyph sites are not found in all areas of the Owyhee uplands. The Trout Creek Mountains, in the southwestern corner of the study area, do not have identified petroglyph sites. This may be due to the vegetative community in which petroglyph sites are found.
Communities of vegetation which occur in Malheur County are playa, sagebrush lava beds, sagebrush scrub and perennial bunchgrass grasslands, ponderosa pine and Douglas fir forest, and mountain big sagebrush scrub, mahogany and juniper woodlands (Figure 3). Archaeological sites are located in all of these vegetation communities except playa (Figure 10). Petroglyph sites are all located in the sagebrush scrub and perennial bunchgrass grassland community of vegetation. The Trout Creek Mountains, where no petroglyphs have been found are in the mountain big sagebrush scrub, mahogany and juniper woodlands vegetation community.
The elevations of archaeological sites in the Owyhee uplands vary considerably (Figure 7). Archaeological sites are found at higher elevations around the Trout Creek Mountains. The cluster there is probably a result of the lush vegetation and higher quantity of moisture that characterizes the mountains, rather than their elevation. Sites also continue to occur in high densities around the Owyhee River from 750 to 1200 meters elevation. Away from the river, in this elevation range and others, the Owyhee uplands do not show clustering of archaeological sites based upon elevation. The elevation of petroglyph sites ranges from 822 to 1859 meters (Figure 9). The lowest elevations come from sites along the Owyhee River, the highest sites, around 1800 meters elevation, are further upstream on the Owyhee. Petroglyph sites do not cluster at one elevation.
This study identified three types of locations where petroglyphs sites are found. Not only do the locations differ, but the reasons for being at the locations differ.
It is possible that the petroglyph sites along the Owyhee River and Jordan Creek are elements of larger site complexes associated with fishing practices. Riverside petroglyph sites could also have been the winter base camps for inhabitants in the region. It is already known that four of the sites with petroglyphs were associated with habitation sites. These interpretations would fit with the local settlement pattern because many of the archaeological sites along the river are thought to be habitation or fishing sites. In either case it is possible that riverside sites could have been aggregation sites.
The water tub sites would have been stopping spots on a journey across large waterless expanses of sagebrush plateaus. This is consistent with the fact that there are practically no associated archaeological features. A small lithic scatter was noted by another observer at one of the three sites. These sites are tied to the water that would be available in the water tubs following rainstorms or snow melt. The area of the plateau where these sites are located is cut off from the Owyhee River by sheer cliffs and there are no water sources in other directions. One of the only safe times to travel across this area would be when water fills the water tubs.
The mesa top petroglyph sites, with their rock walls and wetlands, probably functioned as hunting and gathering sites. The nearby sources of perennial water made finding animals likely and assisted in plant growth. Even if animals were not encountered, a stop at one of these sites could have been profitable because of the vegetative food resources available. Currants and basin wild rye are currently found at all sites and other edible plants went unnoticed in this study. The mesa top sites were also associated with natural shelter created by the rim rock on which the petroglyphs were made. Natural shelter would have been a desirable attribute at a short term camp site. The mesa top petroglyph sites were probably not long term camp sites because the local vegetation and animals could provide only limited resources.
The mesa top petroglyph sites also have rock walls and lithic scatters which indicate extensive use of the sites. Building rock walls would have been a major investment of time and labor. The people constructing rock walls probably planned on using them multiple times to make the effort worthwhile. Additionally the size of the lithic scatters indicates repeated use of the sites. The scatter at 35ML1050 covers 16 acres and that at 35ML1046 covers 6 acres. Despite repeated uses of these sites, the resources available would probably support a small party and not a large aggregation of people.
Some mesa top petroglyph sites appear to have better sources of perennial water and these are the locations which have more petroglyphs, larger lithic scatters, and extensive rock features, specifically 35ML1050, 35ML1044 and 35ML1051.
The environmental context of known petroglyph sites provides clues for where to go to find further petroglyph sites in the Owyhee uplands. The same clues also explain why petroglyphs are not found all over the Owyhee uplands.
The Owyhee uplands are characterized by sagebrush and perennial bunchgrass vegetation. Large areas of the upland plateaus are covered with this vegetation which is not very valuable to humans as resources. The areas where people could find both animals and edible vegetative resources were often associated with water. In essence people would go to specific spots in a barren landscape. People would exploit resources in accessible areas where there was water. Petroglyphs are found where the resources were valuable enough to stop for.
On the flip side, many locations with running water are not accessible to animals or humans. Large sections of rivers and streams are deeply incised in the landscape. Where the canyon is topped by a cliff, neither animals nor humans can easily reach water. Petroglyph sites are only found where water is easily accessible to humans and animals.
The Owyhee uplands are not geologically homogeneous. Features other than basalt cover parts of the Owyhee uplands; these include rhyolite, diatomaceous deposits, new sedimentary deposits and new surface lava (Beaulieu 1972, Orr and Orr 1999). Basalt is the only material on which petroglyphs have been found in the Owyhee uplands. Locations with other geologic compositions are not likely areas for petroglyphs.
Petroglyphs are known to be made on relatively smooth pieces of basalt. Additional petroglyph sites will probably be found in locations where basalt is exposed.
Fires are important to small campsites. The Owyhee uplands are dry most of the year, except in occasional wet years. The desert vegetation is so dry that only one stray ember could start a fire across the plateau. An unprotected fire would be subject to local winds, the anabatic and katabatic winds, that blow across the plateau in both the morning and evening. Rim rock provides protection from winds; this is especially true when boulders away from the rim rock block winds from another direction. The shelter of the rim rock would make fires relatively safe, by keeping the wind from blowing embers away.
The Owyhee uplands are open flat country for the most part. During the summer, the sun is intense in the middle of the day as daily maximum temperatures of the hottest month, July, average 92°F. Also there is little cloud cover and the high elevations receive greater insolation (intercepted solar radiation) because of the reduced mass of atmospheric gasses (Christopherson 1997). The irregular splitting and erosion of rim rock at mesa top sites like 35ML1044, 35ML1045, 35ML1046, 35ML1050 and 35ML1051 provides sheltered locations from the daytime sun. The tall rim rock does not follow a straight line and some concavities create shade at different times of day. Another shelter that the rim rock at mesa top petroglyph sites can provide is from wind. Below the rim, wind is not strong. Two sites in particular 35ML1044 and 35ML1051 have large flat spaces which provided shelter in front of the greatest concentrations of petroglyphs (Photo 34). These spots are protected on more than one side, both by the rim rock and by boulders away from the base of the cliff.
One of the easiest ways to find petroglyph sites in the Owyhee uplands would be to use topographic and geologic maps. Petroglyphs have only been found on basalt in the Owyhee uplands so areas with other compositions could quickly be eliminated. Riverside and mesa top sites, are associated with perennial water sources. Perennial water sources in areas where basalt occurs could be identified on topographic maps. While petroglyphs are not at all spots along perennial water, some areas are more likely to have petroglyph sites. Likely spots include where perennial water is present away from other water sources or where there is access between a river and plateau where rim rock limits free passage elsewhere.
Water tub locations in the Owyhee uplands are not portrayed on maps, to explore more locations of this type in search of petroglyphs, one would need to be familiar with the landscape.
In any search for new sites, it should be kept in mind that petroglyph sites were part of a settlement system. The sites were not solely for the creation of petroglyphs, other activities occurred at the same locations. Activities varied and could have been fishing, long-term residence, gathering plants or hunting.
Mesa top petroglyph sites in the Owyhee uplands provide indirect evidence for dating some of the petroglyphs. Ethnographically, no petroglyphs were known to be created, which indicates that the Shoshone and Paiute probably did not add substantially to the rock art assemblage recently, in the memory of their oral history. The lack of ethnographic data pushes the petroglyphs into an earlier time bracket.
The rock features which are found at 9 of the 11 mesa top petroglyph sites overlook wetlands where animals could be hunted or plants gathered. The site 35ML1045 has rock features similar to the other sites. It is logical to presume that these rock features overlooked a wetland created by the ancient path of Cow Creek. Today the rock features at 35ML1045 overlook the Jordan Craters lava flow. This lava flow is at least 4000 years old (Otto and Hutchison 1977). Therefore the rock features overlooked a wetland that disappeared when the lava flow covered it up. The reasons for people to visit 35ML1045 to hunt and gather disappeared when the wetlands disappeared, at least 4000 years ago. The petroglyphs at 35ML1045 are at least 4000 years old.
The author believes that petroglyphs have been made in the Owyhee uplands for the last 8000 years. The petroglyphs at 35ML1045 are at least 4000 years old. The Owyhee Uplands have little microtopography which would differentially affect the weathering of petroglyphs. Most of the petroglyphs are made on basalt which would probably attain a desert varnish (patination) at a similar rate. Petroglyphs at multiple sites have darker patination (where the petroglyphs are the color of the surrounding rock surface) than the petroglyphs at 35ML1045. One petroglyph at 35ML1045 has a significantly darker patination. This petroglyph and the darker ones at other sites are significantly older than the majority at 35ML1045. The mesa top petroglyph sites are associated with activities which started in the early Archaic, or Uplands Camp phase, around 8000 years ago. The early Archaic is when rock features are first noted (Agenbroad 1976, cited in Andrefsky and Presler 2000:17), and there is an increase in ground stone. Subsistence in the Owyhee uplands changed little over time, fishing was introduced later into a hunting and gathering subsistence. If the creation of petroglyphs is part of the activities of the settlement system, then the petroglyphs have been made for at least 8000 years in the Owyhee uplands.