Excavations at the Sigiri-Potana Cave Complex: A Preliminary Account

GAMINI ADIKARI

In the field season of 1990, the PGIAR excavation and ex­ ploration team visited a cluster of caves at Potana, which held distinct evidence of prehistoric occupation. Within one of the caves, stone and bone tools and other cultural remains were found, lying on top of soil that had been evacuated from trenches dug for the foundation of a building. This site was plotted and registered as MO. 14. As the exploration showed the site to be rich in prehistoric evidence, it was chosen as a site for excavation and further study. The Potana cave cluster (MO. 14) lies 4kms from Sigiriya, on the Dambulla-Sigiriya main road (Lot No. 7.56 12 - Long E 8.45 12). It was decided to excavate cave no. 1 which is about 100-150m above the surrounding flat land, (see fig. 5:1). The cave complex lies within a granite gneiss outcrop. This type of stone is very common in this region (Vitanage 1959; Cooray 1980; Epitawatte 1990). A study of the geo-physical environment of the region was helpful in studying the micro- environmental system in the immediate vicinity of the cave (Bandaranayake 1982; Karunaratne 1989; Epitawatte 1990;). The closest water sources are the Mirisgoni Oya and the Bel- Ian Oya. The interior of the cave is roughly triangular in shape, and has an approximate internal area of 100m". While it is shel­ tered on one side, the southern and western sides are open. The roof of the cave rises at an angle of 45° from the floor. The highest point of the roof is about 8m from the bottom gravel surface. There is a dripledge above the entrance. On the western side of the cave the rock falls steeply, while the slope is very gradual on the southern side. According to its construction, it is possible that the cave would stay dry even in heavy rain. But other evidence shows that the interior had been subject to flooding. There are two possibilities for this: a period of occupation, or reconstruction, and other building activities outside the cave.

Figure 5:1 Sigiri-Potana. Site plan.

Methodology

The entire complex of 12 caves was surveyed and plotted. Excavations within cave no. 1 were carried out stratigraphi- cally. It was originally planned that only half of the cave floor be subjected to excavation, but as the resident bikkhu of the cave was in the process of erecting a building within it, the entire cave had to be

excavated ultimately. The total excavated area of cave 1 was 93m . This excavation was a co-operative effort by archaeologists and natural scientists who helped to analyse the pollen, micro fossils, faunal remains and soil. In addition to the main trench in cave no. 1, a test pit measuring 5m2 was excavated in cave no. 2 (see site plan, fig. 5:1). The matrix system of documentation was fol­ lowed.

Figure 5:2 Map showing location of Potana.

Findings

There were four main layers of soil, with 16 contexts within them. The maximum depth of excavations was lm. Soil specimens from all the layers were subjected to wet and dry sieving. A phosphate analysis of the soil was carried out. In all, about 1,000kg of faunal remains were collected; also a large quantity of mesolithic tools and debris. The most exciting find was of two complete skeletons, lying about a meter apart, in a ‘doubled up’ sleeping position. Human skeletal remains had been found at other prehistoric sites in Sri Lanka (Deraniyagala 1990), but this was the very first find of complete skeletons. They were in an undisturbed layer which has not been dated so far, but there are two very coherent 14C-dates from a context directly above the skeletons. The calibrated age ranges from cumulative probability (using one sigma) are 3913-3727 BC (Ua 5685) and 3916-3709 BC (Ua 5686). Taken as a whole, this analysis is still at a very preliminary stage and will yield exciting material for further investigation. The skeletons especially, will be subjected to intense studies

Figure 5:4 Sigiri-Potana. Radiocarbon dates. Calibrated age ranges from cumulative probability, one sigma (68.28%). CalibETH 1.5b (1991).

REFERENCES:

Bandaranayake, S. (ed.) 1984. Sigiriya Project: First Ar­ chaeological Excavation and Research Report. Colombo: Central Cultural Fund, Ministry of Cultural Affairs.

Cooray, P.G. 1984. The Geology of Sri Lanka, Colombo: National Museum.

Deraniyagala, S.U. 1990. The Prehistory of Sri Lanka : an Ecological Perspective. Ph.D. dissertation. Department of Anthropology, Harvard University, Cambridge, Mass.

Epitawatte, S. 1990. The Physical Environment of the Study Area. The Settlement Archaeology of the Sigiriya-Dam- bulla Region. Bandaranayake, S., M . Mogren and S. Epitawatte (eds.). Colombo: PGIAR.

Karunaratne, P.B. 1989. Report on an Ecological Survey of Forests and Identification of Faunal Remains from Ar­ chaeological sites around Sigiriya. Unpublished Prelimi­ nary Survey Report. PGIAR Archive. Cat. No. 89/26.

Vitanage, W.P. 1959. Geology of the Country Around Polon- naruva. Geological Survey of Ceylon, Memoirs No 1. Colombo: Department of Minerology.