The excavation of Ban Rai rock shelter (Pang Mapha district, Mae Hong Son Province, northwestern Thailand) has uncovered evidence relating to changing patterns of prehistoric human activity. Analyses of the excavation data, along with radiocarbon dating, have enabled the identification of two separate cultural components. The earlier component, the pre-Log Coffin culture, is dated by [sup.14]C to between ca. 12,500 and 8000 B.P. and is characterized by a wide range of lithics, an abundance of faunal remains, and a primary flexed burial. The second component, the Log Coffin culture, probably dates to ca. 2100-1200 B.P. and yielded human remains, potsherds, and iron tools, in addition to the log coffins themselves and their supporting posts. The composition of the artifact assemblages provided the main basis for the separation of the components, which has highlighted the changing use of the Ban Rai rock shelter from a primarily habitation to an exclusively burial site. KEYWORDS: Ban Rai, Log Coffin culture, lithics, Hoabinhian, flexed burial.
THE EXCAVATION OF THE BAN RAI ROCK SHELTER reported here is part of the Highland Archaeology Project, which is investigating cultural chronology and palaeoenvironment in the district of Pang Mapha in northwestern Thailand (Shoocongdej 2000, 2001, 2002a, 2002b). The site had been surveyed and studied by a number of researchers previously (Fine Arts Department 1987; Krajaechan 2001; Sawatsalee 1998; Treerayapiwat 1998), but not excavated. These surveys noted a wide diversity of archaeological evidence including log coffins, stone tools, sherds of pottery, animal bones, and rock paintings. The log coffins, which were used in human burial practices, were dated to ca. 2100-1200 B.P. (ca. 100 B.C.-A.D. 800) (Grave 1995) and can be associated with similar burial practices throughout Southeast Asia (Cheng 1969; Harrisson and Harrisson 1971; Tenazas 1983). The surface evidence at Ban Rai is also very similar to the evidence recovered from Spirit Cave, the first archaeological excavations carried out in Pang Mapha district (Gorman 1970). These excavations indicated that the earliest evidence of habitation was about 12,000 B.P. Gorman defined two cultural periods in the cave sequence, which he labeled the upper and lower Hoabinhian. Carbonized grain in the lower layers was taken as evidence of early agriculture, with cord-marked pottery and ground-stone tools appearing in the upper layers (Gorman 1971; Higham 1977). Although Gorman also found evidence for later Log Coffin burials (which are commonly found in caves in the region), he did not discuss them in any detail. Hence a goal of the Ban Rai excavation was to attempt to provide a detailed cultural chronology of Log Coffin burials in addition to any other evidence for settlement. This paper is, therefore, a preliminary report relating to the excavated cultural layers from the Ban Rai rock shelter, which has proved to have significant evidence relating to changing human activities and usage of the site.
Ban Rai is located at approximately latitude 19[degrees]31'N and longitude 98[degrees]31'E, at ca. 740-760 m above sea level, perched on the southern edge of a steep-sided river valley about 2-3 km to the west of the nearest village of Ban Huai Rai (Ban Hai). (1) The Lang River, at the base of the valley, about 200 m below the site, flows from the east to drain into a sinkhole located just to the west of the site. Ban Rai is one of many large caves and sinkholes located in the karst landscape of this region. The rock shelter measures ca. 105 x 42 m, closely resembling a circular sinkhole in shape. There are many rock falls on the surface of the site, and especially on the western side. The floor of the shelter is uneven along the base of the cliff, although the most significant topographic feature of the site is the general slope away from the sheltered dry areas down toward the unprotected central area (Figs. …