Analytical Techniques in the Analysis of Rock Art

geological formation, is overshadowed by the obvious importance of the peoples who The study of rock art intrigues created this art. Although this is not always archaeologists, ethnologists, art historians, possible, ethnographic accounts can be used and conservationists for many different as an analogy for first hand knowledge and in reasons. The ultimate hope is that art depicted this manner, aspects of nature are given on rocks will shed insight into the minds of qualities of life and power (von Werlhof peoples who came before us. Art is believed 1986:1). Rock, as a symbolic element, has to be an expression of culture and conceptual been cross-culturally included in origin myths processes not otherwise seen in functional of peoples around the world and thought of as tools or artifacts. Rock art is thus studied to a stable and permanent element (von Werlhof hopefully unveil the oldest signs of culture in 1986: 1). The Quechua of Peru believe the oldest rock art sites; to ideally assign a humanity evolved from rock and the Christian point where our ancestors shared culture with bible symbolically names the apostle, Peter, us, Homo sapiens sapiens. This explains the as the rock on which God's church was built. intrigue surrounding Chauvet Caves in Leonard Crow Dog, a shaman of the Sioux, France, the oldest known rock art site to date. believed that rock was here when the world It is epitomized as a decoding key, unlocking began and claimed it to be the very womb of the mystery of cognitive processes otherwise mother earth (von Werlhof 1986:1). The absent from us in the archaeological record. In Ojibwa Indians of Lake Superior maintained essence, the study of rock art is the study of the natural world through respect and ritual ourselves, to understand why art is a part of observances where the pictograph sites record who we are and what it represents about us, their native religious traditions that combine all the while linking us to the past. Jones an understanding of the spiritual and physical (1981 :2) describes the cultural perception that landscape (Conway and Conway 1990: 1). In highly structured social institutions such as some ethnographic instances, the power, or religion dictate low variation in artistic style, mana, within the rock cannot be released until giving us an example of the information that the art, or spirit, is applied by a shaman (von can be extracted from rock art sites. Werlhof 1986:4). The study of rock art is Rock art sites appear throughout the therefore believed to be the spatial world, from North and South America to manifestation of the synthesis of the shaman Europe, Asia, Australia, and Africa. All rock and the rock (Conway and Conway 1990:1). art sites, however, invoke a feeling of Art involves a "selection from life spirituality inspired by the beauty of the experiences of the artist and a symbolization scenery and majesty of the rock. Often the ofthis in a manifest form" (Jones 1981:2). In symbolism of the canvas, in this case the other words, studying rock art may divulge information regarding daily life. Before interpretation, however, the art and the canvas must be scientifically analyzed, requiring accurate methods of recording the data as well The first step in recording a rock art as numerous ways to date this cultural site is the discovery. This term, however, resource. implies that most sites are lost but in reality, Rock art refers to two-dimensional many sites are still considered spiritual and depictions on horizontal or vertical rock sacred places by the descendants ofthe artists. surfaces and for the purposes of this paper To discuss the "discovery" of the site is to will refer to art on parietal or rupestral disregard indigenous knowledge (Conway and (immovable) rock surfaces (Jones 1981:1). Conway 1990:8). It is possible, however, to The two major types are pictographs, also bring a site to national attention like the known as rock paintings, and petroglyphs, national explorer, Selwyn Dewdney, who commonly referred to as rock engravings or brought national acclaim to the Agawa rock carvings outside North America (Jones art site on Lake Superior in 1958 (Conway 1981:2). Pictographs are an additive process and Conway 1990:8). Like most other in which a substance, itself containing "discoverers" of rock art sites, Dewdney used information, is added to the rock just as the historic accounts of early explorers to find his pigment alone in a drawing, or with wet way (Conway and Conway 1990:8). Other pigment used in a painting. It is nearly common and frequently used methods are impossible, without chemical analysis, to sources who know the landscape like determine if the pigment was wet or dry when indigenous peoples or tour guides, applied (Bednarik 1992:279). Therefore, for documentation from archaeological societies the purposes of this paper, the terms painting of a given region, and local newspapers and drawing will be interchangeable. The (Jones 1981:7). paint added to the rock surface contains one Another direction to follow is the use or more pigments, the substance providing of ethnographic information. Certain colour. In some cases binders, extenders, and geological formations are often considered liquid bases are also included (Bednarik sacred sites to aboriginal peoples. For 1992:279). Petroglyphs are a created by a example, the Ojibwa view the cliffs of Agawa deductive process involving removal of part Rock as 'cut rock" places where the earth's of the rock and it is through the pecking, energy is exposed (Conway and Conway abrading, or etching that most technical 1981: 11) and von Werlhof(1986:2) describes information regarding the feature is obtained the practice of Australian Aborigines applying (Jones 1981:1-2). Pictographs provide a art to rock surfaces precisely because of the substance that can be dated and in most cases peculiar qualities ascribed to the rock. the production of the pigment is concurrent Understanding the spirituality of indigenous with the painting in archaeological time. This peoples may provide clues to a geological element is missing in petroglyphs (Bednarik pattern of sites. However, not all sacred sites 1992:279). It is this major difference that of the Ojibwa have rock art, but it is this leads to differences in recording and method of looking for patterns that can aid in analyzing petroglyphs and pictographs. This the search for sites. A similar pattern was paper will discuss the methods and case used for the Churchill River sites, studies of discovery, recording, and dating of Saskatchewan, where the archaeologists rock art. looked for geological patterns such as site location, type of rock (granite versus basalt), and formation of the rock itself (crevice, cave, artifactual and non-artifactual features or outcropping) (Jones 1981:8). The Chauvet resulting from human behaviour. This is in Caves site in France was discovered by contrast to the conservator who requires speleologists and archaeologists exploring chemical, physical, and mineralogical data different caves in their spare time (Chauvet et focusing on the colour, surface texture, al. 1996:20). porosity, and form of the rock and art for deterioration studies (Rosenfeld 1978: 11). The needs of each are not exclusive, and can be facilitated in the same recording system Selwyn Dewdney was the first rock art while maintaining efficiency and economy. researcher in Canada and in his writings In the recording of rock art sites, discusses some of the first known recordings another issue to be addressed is the degree of of petroglyphs in Atlantic Canada (Lundy detail or accuracy. A common frustration in 1977:1). George Creed was a village rock art literature is the misrepresentation or postmaster who recorded these petro glyphs by inaccurate representation of images (Dewdney filling in the delicate grooves with indelible 1979:325-6). Rosenfeld (1978: 1) asks the pencil and pressing damp paper into the question, "What levels of detail and accuracy engravings, thus transferring each figure are required, how comprehensive should (Lundy 1977:1). Site reports until the 1950s records be?" To answer this question, the included crude freehand sketches by field purpose of research needs to be addressed. He assistants or hasty sketches by passing does, however, feel that sites in immediate geologists (Lundy 1977:2). New techniques danger should be recorded as accurately as for recording pictographs and petroglyphs possible and although this may not be the have been developed due to the technological most economical solution in which funding is innovations developed in the most common concerned, unexpected natural or human- forms of recording rock art such as tracings, induced disasters may result in the rubbings, and photography. obliteration of inappropriately recorded sites Within academia, two audiences exist that were assumed to be safe. Rosenfeld requiring different types of information: the (1978:10) does recognize a feedback archaeologist, ethnologist, and the conservator relationship between information recorded (Rosenfeld 1978: 11). The basic premise ofthe and research developments: that an increase in archaeologist in any archaeological data recorded facilitates and inspires more investigation is to obtain as much information specific areas of inquiry. as possible in the advent of destruction of a Another potential danger exists in the site resulting from excavation or natural verbal description of rock art (Dewdney disaster. As well, future research endeavors 1979:326). Verbal descriptions are often are not known and it is therefore ideal to culturally loaded, implying images of collect information pertaining to the original typologies rather than descriptions of the research question. It is Rosenfeld's (1978: 10) actual image. For example, Dewdney opinion that accuracy fulfilling future (1979:326) describes the danger of descriptive research requirements can amount to no less terms such as 'man' to an androgynous figure. than an obviously impossible complete replica Typological classification systems allow a at the atomic level. Hence, his solution is uniform manner in discussing images despite conservation and preservation. The variations. Unfortunately, this brevity in archaeologist is concerned with past human description leads to inadequate behaviour and, therefore, focuses on representations and affects the interpretations offuture researchers. The assignation of types economical, and allow control over which results in premature interpretations rather than traits are recorded (Rosenfeld 1978:13). Jones descriptions (Rosenfeld 1978:9). Dewdney (1981:8) developed his own specific tracing (1979:328-30) discusses the clear presence of method used for the Churchill River rock art distinct styles in some pictographic sites. In this case, transparent film material assemblages, but also the almost complete such as Saran Wrap was adhered to the wall lack of symptomatic or diagnostic features in using masking tape and to each other, if others. Failure to recognize this leads to loss required, by transparent tape. of information. In effect, the issue is the information. Major discrepancies exist in A fine felt of fibre-tipped pen using a coded typological classification. with indelible ink was used to Alternatively, the use of gradation following trace the figures. Care was the Munsell colour chart in which scales of taken to ensure that the outer style values and gradations between pairs of edges on the tracings opposites are recorded is suggested (Dewdney corresponded exactly with the 1979:328-30). outer edges of the paintings. Dewdney (1979:328-30) advocates the Red pens were used for multivariate use of visual and verbal paintings, while blue was descriptions in an attempt to holistically usually used to delineate record data and avoid interpretation. lichen or moss growths, and Unfortunately, the lack of standardization in black for cracks, chips, or requirements decreases accuracy in most other features in the rock face. visual representations and offers examples of Notations about special differences in visual representation of the features were made on the same image. Overall, Dewdney's (1979:328) margins of the tracing. (Jones position is that more accurate recording 1981:8). procedures and attitudes must be adopted to eliminate the inconsistencies seen in the Items such as water level and direction archival rock art literature. Therefore, when were also recorded in the field notes. Tracings recording rock art sites, one of the most on mylar for petro glyphs have been used but important factors is the attitude of the are generally considered to miss important researcher and his/her utilization of the details ofthe petroglyph (Cameron 1979:366). methods described below. Unfortunately, the reproduction that results from tracings is two-dimensional whereas the surface being recorded is three-dimensional (Rosenfeld 1978: 11). This loss in dimension The most common method of results in a loss of detail and accuracy. recording rock art sites includes a Tracing sheets require dimensional stability combination of techniques such as and transparency (Rosenfeld 1978: 13). photography, tracing, rubbing, and moulding Alternatives to Saran Wrap are sheet or casting (Taylor et af. 1979:310), all polyethylene and acetate sheets. supplemented with extensive field notes U nfortunatel y, the former stretches (Dickman 1986:152). Tracings are the most irreversibly and although the latter is durable common means of recording rock paintings and does not stretch, it is unsuitable for because of the potential to produce more archival conditions due to long-term chemical accurate results than freehand sketches, are instability (Rosenfeld 1978:13). Rubbings for petroglyphs are the tape. The translation ofthe rubbing is affected equivalent to tracings for pictographs. Walker by variables such as weather conditions, et al. (1979: 341) describes rubbings as the attitude of the researcher, and variation in best method for recorded carvings. They slant or direction of wax as it is applied to the provide ideal overall scale although they often cloth (Cameron 1979:367). There is also the include lines that are fissures and exclude danger of drawing rather than interpreting in shallow lines of the engraving. Another the accentuation of nuances. problem is the role of the archaeologist as Another method for recording interpreter. Factors such as width of the line petroglyphs is aluminum foil casting and is are at the discretion of the interpreter and based on its malleable nature (Clegg objectivity may be lacking (Cameron 1978:22). The premise is that when applied to 1979:367). Differing depths ofthe grooves are a figure, the side of the aluminum foil that is also not conveyed in rubbings (Walker et al. in contact with the material under study 1979:342). provides a very close negative reproduction of The procedure followed by Walker et the surface detail with an accuracy of one part al. (1979:342) is to first photograph the in one thousand for a metre-sized engraving petroglyph, make an initial rubbing, (Clegg 1978:22). The method basically photograph the rubbing, and compare the consists of loosely covering the area with tin photograph with the site. Corrections are foil and tamping it. The action is marked on the photograph and the petroglyph perpendicular to the surface which helps was then rubbed again using the photograph avoid tearing while maximizing details by as a guide. This process is then repeated as stretching and moving the foil until it settles necessary while dealing with factors such as into the grooves. The thickness is built up to weather, seasonality, and isolation of the site three or more sheets of foil and the deepest and can take up to two years to complete one grooves are reinforced with masking tape. The rubbing suitable for archives (Walker et al. next stage strengthens the aluminum foil for 1979:343). Cameron's (1979:366) preferred transportation by gluing on three or more technique for recording petroglyph sites is layers of cloth or paper before removal from surface printing with cloth and wax. An the rock (Clegg 1978:23). The cast is unbleached, clean, cotton cloth such as muslin protected with foam plastic on both surfaces is adhered to the surface with masking tape. and transported on a carrying board. The cast The fabric is then sprayed with water, is then used to produce a fibreglass or other readjusted, re-taped, and allowed to dry type of permanent and robust positive slightly (Cameron 1979:367). The wax is best reproduction of the engraving (Clegg applied when the cloth is slightly wet and is 1978:25). However, areas larger than 1 m2 and usually cobbler's wax for larger abraded grooves deeper than 1 em produce problems glyphs and harder stick wax for incised in transportation. The advantage, aside from designs. A supplementary photographic record cost, is that detail otherwise unnoticed is is used to compare the rubbing and the accentuated by the shine of the foil (Clegg original surface. The final rubbing is easily 1978:25). stored, photographed, or dry-mounted for display (Cameron 1979:367). Some factors that could impede the wax-and-cloth rubbing method are exfoliation Photography is first used as a of the wall, sunlight melting the wax, and descriptive tool but can also be used as an aid humid conditions preventing adherence of the to evaluation and observation (Rosenfeld 1978:2). When photographing a rock art site, to handle in confined spaces, photographs at it is important to remember to not only horizontal angles are difficult to use, complex photograph the technical aspects of the site, rock morphology can contain projections but also the site with the distortion as obliterating areas from the camera's field of perceived through the observer as this may be view, and the special skills of a the artists' intended effect. Photographs that photogrammetric plotter are required should be taken are; general site views, (Rosenfeld 1978: 13). Another disadvantage is surrounds ofthe site, specific areas of the site, that because the area covered by each set of groups of figures, individual figures, and stereo photographs depends on the length of details within figures. Control of the the baseline where detailed work requires a equipment, angle, lighting, and filters can short baseline and vice versa for more general allow photography to record details not views, a wide range of camera equipment is otherwise visible to the naked eye. Polaroids required to provide an exhaustive are excellent in preliminary site evaluation photogrammetric record of the site (Rosenfeld and as a supplement to field notes, and 1978:14). macro photography has also been used in An inexpensive alternative to studies of technical aspects of engravings photogrammetry is the use of (Rosenfeld 1978: 12-13). The basic premise of stereophotography. Clegg (1979:25) adapted nightlite petroglyph photography is the control a method of creating stereopairs using a of the light source at night to accentuate the normal camera in which the first picture is details of the carvings by manipulating the taken with his weight on one foot, then shadows in the grooves (Walker et another with his weight on the other foot. al. 1979:341). An added benefit is the Julesz (Clegg 1979:26) has shown that "animation" of the petro glyphs as the light "stereopsis can be obtained perfectly well source is moved along different angles. even if one picture is larger by 15%, out of Unfortunately, photography may not always focus, or tilted compared with its pair." In produce satisfactory results when used in effect, the precise placing of the two petroglyph sites that are highly eroded or viewpoints is not critical. pictograph sites lacking distinct contrast (Cameron 1979:366). However, experimentation with equipment and lightsources by Walker et al. (1979:341) One of the difficulties in studying rock during the rescue excavation of the art is dating, for which there are two petro glyphs of Ringbolt Island, B.c., classifications (Bednarik 1996: 1). Internal or improved the accuracy of the rubbings by direct dating takes the information required clearly identifying groove widths and depths. for dating from figures themselves through Photogrammetry is a plotting the pigment or the image or subject itself The technique using stereoscopic photographs to second is external or indirect dating and provide a precise, three-dimensional record includes gleaning information from the (Taylor 1979:310). It is often used in site archaeological layers covering the painting, survey because maps can be redrawn with topographical relation within the different selection of traits or scale from the archaeological layers, and stylistic same photos without returning to the site and comparison (Bednarik 1996:1). The major the actual fieldwork is quick and consideration in each dating technique is what uncomplicated (Rosenfeld 1978: 13). is being dated and how that date relates to the Unfortunately, the equipment can be difficult event resulting in the rock art. The following is a discussion of several types of relative quests (Conway and Conway 1990:53). dating methods, the radiocarbon dating of the Stylistic comparison has been used, however, Chauvet Caves in France, and a review of the in sites in France and Spain where rock different methods used to date the Coa Valley engravings closely resemble engraved designs petroglyphs of Portugal. on animal bone found in dated archaeological deposits (Keyser 1992:18). It is the similarity in style that links the rock art to the dated archaeological layer. The possibility of Lichenometry is the dating of lichen, independent innovation in two groups, a symbiotic relationship between fungi and however unlikely, is disregarded. It is also algae that grows in harsh conditions such as possible that the people responsible for one the side ofa rock face (Jones 1981:62). It has medium, portable or parietal, discovered the been proposed that it is possible to date lichen other and copied it onto their chosen form. and therefore show that the encroached upon Although proximity may indicate a rock art is older than the lichen. This is relationship between the two stylistically extremely difficult, however, because the similar items, it cannot be assumed that growth of lichen is dependant upon the relationship is one of temporal continuity. microenvironment unique to each cliff face Stylistic seriation assumes style is a function and growth ofthe lichen may be too minute to of time and cultural continuity, giving no detect in a realistic time frame (Jones credence to individual or functional variation, 1981:62). Another disadvantage is that or reversion to a previous style. conservation efforts or recording techniques It is sometimes possible to date rock such as tracings usually result in the removal art sites when the panel is covered by of the lichen from the rock surface. sediment containing dated archaeological Dating using stylistic senahon artifacts (Keyser 1992: 18). One situation assumes that change in style is a function of involves the accretion of sediment against the time, and that change in style reflects a intact panel, the other is the accretion of change in the material culture. The possibility sediment over a panel that has fallen (Keyser that change in style is a reflection of 1992: 18). In both situations, a minimum age functional or individual variation would relate boundary is given because it is logically older to site types rather than regional distribution than the sediment covering it. A maximum of sites (Hyder 1989:4). The basis for age is not determined unless the panel fell on determining which style is older is the use of to a datable archaeological layer (Keyser superimpositions. When a picture is painted 1992: I 8), and may be questionable even then. over another from which it is stylistically In some cases, the subject matter of distinct, it is said to be younger than the first. the images is considered a direct dating This is an age relative to the other styles seen method (Bednarik 1996:1). I am discussing in the area (Keyser 1992:19). In many cases, them as relative dating methods, however, like the OJibwa rock art, there is not an because rather than a time range given with adequate number of superimposed paintings radiocarbon dating, only a maximum time to develop a style seriation (Conway and range is possible. Clearly represented historic Conway 1990:53). Ethnographic evidence of items such as horses, guns, wagons, European the Wabemo medicine men illustrates Americans, and buildings are post-contact in different styles used at different times, but age (Bednarik 1996: 1). Depictions of people also used at the same time and the abstract mounted on horses are dated to after A.D. style of animal paints was used only in vision 1720 on the Columbia Plateau when horses were first introduced by Spanish settlements 'zeroed', allowing comparisons of silcrete in New Mexico. Bednarik (1996:]), however, skin development. feels it is inappropriate to use depictions of animal species as a method to date rock art. Many purportedly "identifiable" animals are depicted in distorted manner. To assume Radiocarbon dating has long since knowledge of the proposed image or species been a valued tool in dating archaeological is to first assume the cognitive processes of finds. Its application in rock art sites, the artist and the observer are the same and however, has been limited until recent that the archaeological distribution of a advances have decreased the amount of species accurately reflects the actual organic material required (Conway and distribution (Bednarik 1996: 1). Conway 1990:51). In the past, the amount Weathering offers a relati ve required was usually more than available in a chronology of pictographs and petro glyphs single pictograph and meant the destruction of exposed to the same microclimate; images on the painting. Or, if the samples from more the same panel can be placed in relative than one pictograph were used the dates were chronology bases on the degree of weathering criticized as being contaminated because each to which each has been exposed (Keyser pictograph may not have been drawn at the 1992 :20). This is based on the assumption that same time (Chauvet et al. 1996:12). This each image had the same origin; the same could result in an interpretation stating that thickness of paint applied, the same dilution the picture was later redrawn. In any event, of pigment in the paint, the same weather the date produces a maximum age for the conditions, and that the weather over time is pictograph, which is valuable in itself. I will the only factor affecting differences seen in use the dating of the Chauvet Caves in France the art today (Keyser 1992:20). A major to illustrate the application of this technique. component of using weathering is rock The dating of the pictographs at varnish. Small amounts of dissolved or Chauvet Caves has been made possible first suspended mineral ions such as silicon, by advances in analysis of the paints form the aluminum, and calcium in the water form a original chemical analysis to scanning durable, protective coating on the rock after electron microscopy, X-ray diffraction, and evaporation (Do1anski 1978:32). This semi- proton-induced X-ray emission (Chauvet et al. impervious layer is formed by the physio- 1996:11). Originally, the black paint was chemical reaction of water evaporation believed to be manganese dioxide. These causing concentration of silica at the rock chemical tests have since shown that, in most surface. The silica is then nucleated by metal cases, the black paint is charcoal and only in oxides on existing quartz grains as some instances is it coated with layer of overgrowths resulting in the pigment manganese dioxide (Chauvet et al. 1996:12). becoming part of the rock, interjacent to the The second advance was the development of silica and the rock. In rock paintings, this Accelerator Mass Spectometry (AMS) which decreases the weathering process, thereby requires much less of the sample than hindering dating using the weathering process. conventional radiocarbon dating. These In petroglyphs, however, it can be used as advances have resulted in dates showing means to differentially date images on the Chauvet Caves to be the oldest known rock same rock face (Dolanski 1978:32). When the art site. The problem remains in petroglyph is created, rock with the silcrete interpretation. In addition to the debate skin is chipped away and the clock is regarding the dating of the charcoal discussed above, problems of calibration and samples were also taken outside of the contamination in the sample from the time it petroglyphs (Dom 1997: 106). The previous was collected through to analysis in the lab assumption was that the silica coatings are still exist (Chauvet et al. 1996: 12). At the closed systems; there is no exchange between time of publication in 1996, the radiocarbon the atmosphere and silica coatings. However, dates were uncalibrated and the given Dorn (1997:113) found that there is a slow confidence interval translates to the true age organic carbon exchange between the silica having a 68% chance of falling into the time glaze and the contemporary environment and span given. In other words, one third of the that using a formula to compensate for this dates may be false. The result is a reluctance rate of exchange results in a measured age of to rely on one date. In this instance, Chauvet approximately 5000 years ago equaling a true Caves has challenged these criticisms in that age of 18 000 years B.P. This system of open- a series of congruous dates has been provided air radiocarbon dating has so far only been (Chauvet et at. 1996:12). used in soils, but Dom applied this to petroglyphs and found that the grooves could have received a large influx of then-modem carbon in the Palaeo lithic when rock faces The Coa Valley petroglyphs of were exposed to a subaerial environment. Portugal were discovered in 1994 and have Subsequent slow rates of post-engraving since become a major area of debate in an carbon exchange would have produced the effort to save the petro glyphs from the Holocene ages previously observed (Dorn flooding they will be subjected to if the 1997:113). proposed Coa Valley dam proceeds (Dorn Dorn (1997: 112) also looked at micro- 1997:105). For this reason, there has been erosion of the quartz and found that it could pressure to assign a date to these petroglyphs not be used as a dating technique because of to establish an origin of Holocene Pleistocene the presence of the silica glaze. The basic age. Radiocarbon dates of the rock coatings premise of micro-erosion is optical relatively date the engravings as younger than observation, in which chemicals have not 1700 B.P. whereas micro-erosion and style "...accelerated or retarded the development of suggests a maximum date of 7000 years ago erosion phenomena, petroglyphs to be (Dom 1997:105). Dorn(1997:105) attempts to analyzed must be of mineral accretions, or constrain the dates by using a combination of other natural deposits concealing them" radiocarbon dating, micro-erosion, and (Bednarik 1992:281). This describes silica geomorphic instability. The silica glazes glaze and assumes that the quartz on which contain the only organic carbon available for the carvings were engraved was previously dating petroglyphs and because the silica unweathered. Quartz weathers internally glaze forms over the glyph, the dates will before it is exposed at the surface and the provide a minimum age. Carbon was dates would then be overestimated (Dorn extracted from five contexts associated with 1997:113). As well, the complexity of the the carving; pore spaces of rock weathering quartz grain as it becomes weathered is not rinds on exposed panel surfaces, within completely understood. weathering rinds within the petroglyph Geologically, the Coa Valley is grooves, weathering rinds collected from the claimed by Watchmen and Bednarik to be unexposed rock crevices, organic matter " ...too unstable to support Palaeolithic art on between the rock and the coating, and a the grounds of 4000 to 6000 B.P. sample from within the silica glaze. Control luminescence ages [due to] inset river sediments, close proxImIty to the river but a few means that have been developed in channel and flooding, and slope instability" a field of study that advantageously (Phillips et al. 1997: 100). Chorine-36 analysis incorporates many disciplines in its analyses was used to date the exposure of the rock and the development of new and accurate faces; if the faces were only exposed in the recording techniques illustrate different Holocene, the engravings could not be perspectives on the purpose and meaning of Palaeolithic (Phillips et al. 1997:100). the sites that can be explored. Chlorine-36 dating is based on the amount of cosmogenic nuclides in minerals at the rock face produced by reactions of cosmic-ray particles with elements in the atmosphere or Bednarik, R.G. 1992. A New Method to rock. This phenomenon occurs only in the Date Petroglyphs. Archaeometry first 1 to 2 m of rock. Therefore, newly 34:279-291. exposed rock surfaces will have less cosmogenic nuclides than those exposed for Bednarik, R.G. 1996. Only Time Will Tell: longer periods of time (Phillips et al. A Review of the Methodology of 1997: 100). The results of this study show that Direct Rock Art Dating. the engraved panels were exposed and Archaeometry 38:1-13. available for carving during the Palaeo lithic (Phillips et al. 1997:100). In summary, the Cameron, J. 1979. "Petroglyph Recording Coa Valley petroglyphs have undergone many Techniques." In Papers from the different dating techniques and as of yet, the Fourth Biennial Conference of the only definitive answer is that a Palaeo lithic Canadian Rock Art Research age could not be falsified. The example of the Associates. Lundy. (ed.). pp. 365- Coa Valley petro glyphs shows the wide range 368. British Columbia Provincial of techniques available to date a particular Museum Heritage Record No.8. site and that these techniques do not guarantee Victoria, British Columbia. answers. Chauvet, 1M., E.B. Deschamps, and C. Hillaire. 1996. Dawn of Art: The Chauvet Cave, Oldest Known Rock art is studied as a means to Paintings in the World. London, understanding past spiritual relationships of England: Thames and Hudson Ltd. the artist with the landscape and as a method of extracting information regarding daily life. Clegg, J. 1978. "Simple Field Techniques Art is also generally believed to be a trait for Recording Engravings by Casting specifically reserved to humans with culture. and Stereophotography." In Although highly debatable, this premise is Conservation of Rock Art: used in trying to determine the earliest signs Proceedings of the International of culture. The methods used to extract this Workshop on the Conservation of information have a direct relationship with the Rock Art, Perth. Perth. (ed.). pp. 22- information available for study and for this 26. Sydney: The Institute for the reason, improving and standardizing Conservation of Cultural Material. recording and dating techniques are believed to be imperative by many researchers in this Conway, T. and J. Conway. 1990. Spirits on field. The methods discussed in this paper are Stone: The Agawa Pictographs. California: Heritage Discoveries History No.4. Regina: Saskatchewan Publication. Department of Culture and Youth.

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