The fact that, except for the chance find of a single palaeolithic tool from Chhagalnaiya, on palaeolithic site could be located in the territory of modern Bangladesh comes as a surprise.One must remember that there are large Pleistocene deposits in Bangladesh and that palaeolithic men had lived during the Pleistocene period. One must also recall that, although there is an almost total absence of suitable rocky material forpalaeolithic implements in Bangladesh, fossil wood occurs in reasonable quantities in many of the areas with Pleistocene deposits.The Barind tract of the northern part of Bangladesh, the Madhupur tract of the Mymensing and Dhaka districts, the Comilla-Noakhali hills of which the Lalmai hills are a part, and the Chittagong hilly areas are the major instances of Pleistocene depositsin Bangladesh. The hypothesis could be checked in the field in the Lalmai area only in the early part of January 1989, and on the very first day of my personal exploration of the area it was possible to locate a stratified palaeolithic occurrence. The next spell of fieldwork, this time with the support of the archaeology project of the JahangirnagarUniversity, took place in April 1989 and resulted in the discovery of ten more palaeolithic occurrences.The Mainamati-Lalmai complex of hill, about 8 km long and 4.8 km wide at its maximum, extends from the Ranir Bangla ridge on the Comilla-Brahmanbaria road in the north to the vicinity of the Dhaka-Chittagong railway track in the south. The average height of this upland from the level of the surroundingplain is about 12 m, with some individual spurs rising up to a height of 30-50 m. The northern part of this complex of hills is known as the Mainamati hills whereas the southern section is called the Lalmai hills. Basically this tract shows a spread of rolling uplands intersected by depressions. wherever the cliff- like formations are cut they show a clear cross-section of yellowish sandy material which is leached a little red towards the top. One can also observe some small nodule concretions and very rare small quartz pebbles in the section. Formerly, the area was given over to the jhum or slash –and-burn method of cultivation by a group of trials called the Tipras. Now the settled farmers use this area for vegetable cropping on the slopes and tops of the ridges and for normal rice cultivation in some of the depressions between the ridges. Vegetation has worn thin but one can notice stumps of sal, jack fruit and mango trees, apart from bamboo groves, etc. The area explored by us falls in the south and southeastparts of the ridge. Our search for prehistoric tools was conditioned primarily by the distribution of fossil wood chunks which were used as raw materials. At the same time, we noted that not all types of fossil wood were preferred as raw materials. There was a distinct preference for only those pieces which showed below the cortex or surface skin a rather hard and flinty deep brown or darkish material. This shows that the prehistoric people concerned were closely familiar with the properties of fossil wood chunks of the area and their distribution.
The mound of Bihar is only a kilometer south of Bhasu vihar and encircled y the Nagar river .It was excavated in 1979-83.The major discovery has been that of a monastery, the plan of which has been full obtained .It measures 57 m by 61 m and contains 37 monastic cells in all around the open courtyard: 10 each in the northern and southern wings 8 in the eastern wing and 9 in the western wing . The gateway projects outward from the center of the eastern wings. It was flanked on the outside probably by two guardrooms which survive in the form of two structures, each measuring 6.33 m by 5.9 m. A staircase led to the outer hall which also contained a brick platform with a semi circular structure at the base .The inner entrance hall is linked to the inner verandah from where a staircase with 3 steps goes down to the open courtyard .The monastic cells measure 3.3 m -4.5 m by 3.3 m. The partition walls are 1.5 m thick. The outer wall of the monastery which also the back wall of the monastic cells is 2.6 m thick while the thickness of their front walls 2 m . The lone surviving example of a door is 1.4 m wide. In two cell s of the eastern wing pedestals for image shave been found .The verandah is uniformly 2.7 m wide , with the western part of the southern wing showing a brick platform . The thickness of the retaining wall of the verandah varies from 1.3 m in the eastern and western wings to 1 m in the northern and southern wings . Deep digging revealed to conductional phases of the monastery, one built on the top of another without any alteration in the layout .The ruins of possibly another monastery were exposed to the south of this monastery the outline of which could not be fully obtained. Five monastic cells were excavated. One of them was found to possess a 2.2 m square platform . The back wall of these cells id 2.5 m thick and the thickness of the front wall is 1.8 m. The partition wall is 1.2 m thick. The southeastern portion of the mound showed the ruins of a temple with a high superstructure based on an irregular series of blind cells. It appears that the sanctum of the superstructure was built over the massive squares central cell of the cellular structure. This central cell internally measures 4.6 m N-S by 4 m E-W and externally 9.6 m N-S 9 m E-W. The massive eastern and western walls of the cell are 2.7 m wide and northern and southern walls are 2.5 m wide. Other subsidiary cells encircle this central cell in several rows on its four sides .The major antiquities discovered at the site are one silver coin of Sultan Sikandar shah , thirteen terracotta plaques , two terracotta seals, a few decorated bricks , miniature earthen pots , oil lamps , lids , glass bead ,terracotta beads balls toys,, net sinkers, bronze pieces , red , ochre’s , and iron nails.