The presence of charcoal in the two squares inside the tunnel comes to a halt in levels deeper than Level 28. However evidence of burning activity is seen as understood by the presence of black stains on stone pebbles both small and big. These have been noticed till Level 51. In the square XA1 in Level 44, stones were found to have thin film of black colour, which has been formed by the penetration of carbonaceous matter in the porous sandstone. Similarly, the presence of lime wash was noticed at lower levels till about Level 40, below which it becomes scarce. It appears tentatively that they used to use lime quite early. Perhaps discovered accidentally on roasting shells with the mollusca inside it. However such evidences have not been reported from early contexts, elsewhere.
To search the palaeo-environmental backdrop of human activities in the past palaeo-botanical and soil samples were collected. The soil samples are being collected at every 5 cm depth and would be amenable to P.S.A., XRD pH, phosphate, nitrate, carbonate analysis. Select samples showing characteristic features in soil has been collected for micro morphological studies. Sieve analysis of the soil of each level is being done.
Further excavation has been carried in 2003-2004 out in the two sub spots namely inside the tunnel and beneath the projecting ledge near the mouth of the tunnel in the rock shelter. At both the sub spots the earlier squares (131m) were excavated to greater depths. In squares XA1and A1 inside the tunnel the digging was carried out from level 52 to 80 and beneath the ledge in squares C8, C9, C10, D8, D9, D10, E8, E9 and E10 the process continued from level 12 to Level 15. Due to the widening of the tunnel at the bottom a new square XB1 was laid out in part, from Level 61 and continued till Level 80. In line with the objectives of the excavations for reconstructing environmental and intra-site differences the excavations were undertaken incorporating maximum possible documentation. Besides taking relevant data of natural clasts its position on X, Y and Z axis, orientation, length, breadth, thickness and weight, soil samples were collected from each of the 16 grids in each square of the excavation at intervals of about 5 cm. Flotation of excavated sediments has yielded floral and insect remains.
The continuity of human activity is seen in the lower levels inside the tunnel. However there is a marked reduction in number of artifacts compared to previous two seasons of works. Inside the tunnel the human effort is understood by the presence of natural flakes with varying number of negative bulbs of smaller flakes that had chipped away during the course of use. Beneath the ledge the excavations has yielded artifacts such as: blades, backed blades, lunates and cores besides debitage and raw material (chalcedony). Some potsherds of crude red and gray core have been found in the Mesolithic assemblage. The presence of raw materials, nodules of chalcedony, debitage and cores indicates it as a factory site.
The last excavation was carried out in 2004-05 in the Rock Shelter no. ASI-28 at Bhimbetka. The excavations were continued in XA1, A1and XB1 square inside the tunnel from levels 81 to 100 and beneath the ledge in squares C8, C9, C10, D8, D9, D10, E8, E9 and E10 from level 16 to 27 .
In the limited area excavated within the tunnel the general trend of decrease in artefactual remains observed last year, became more pronounced in the levels dug during the current session. The square beneath the ledge yielded Mesolithic artifacts such as blades, backed blades, lunates and cores besides the raw material, chalcedony and debitage. Evidently the microliths were prepared at the mouth of the rock shelter.