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Prehistory Evidence of prehistoric and protohistoric human habitation and culture have been discovered in many parts of the Bengal basin. Attempts have been made to correlate such evidence especially the tools, implements and other archaeological materials uncovered' geologically and geomorphologically with the landscape, sediments and soils for dating so that meaningful and reliable inferences could be made about the culture.

The Ganga-Brahmhaputra river system forms the world's largest delta. Also known as the Bengal basin, it covers most parts of present day Bangladesh and West Bengal. The blanket of Quaternary alluvium of the Ganga, and the Brahmhaputra, and their several tributaries and distributaries conceals beneath it almost all the older rocks of the Bengal basin. Geologists postulate that the Bengal basin is a mio-geosyncline formation which signifies orogeny-related mobile downwarping of the basement rocks in the creation of a subsiding basin where sedimentation continued without volcanism throughout the Cenozoic (66 million years to present) period. This resulted in the sinking of the basin to a great depth and in the accumulation of sediments of great thickness. At the time of down wrap movement, the subsiding Bengal Basin also experienced periodic pulsation of uplift and subsidence, resulting in corresponding marine regression and transgression that's led to continental and marine sedimentation. This resulted in the uplift of the Shillong massif and formation of the Garo-Rajmahal basement ridge as well as the development of the Tertiary (66 million years to 2 million years before the present age) folded belt of Tripura.

To the north of the Bengal Basin occurs the orogenic Himalayan belt along with Foredeep as its integral tectonic component. Just south of the belt are the two outcrops of the same Archean-Proterozoic cratonic mass, joined at the subsurface of the Garo-Rajmahal basement ridge or the Garo-Rajmahal saddle. Thus the northern limit of the Bengal Basin should actually be considered as terminating at the Garo-Rajmahal saddle. The portions of West Bengal and Bangladesh lying to the north of the Garo-Rajmahal constitute a part of the sinking trough of the Ganga-Brahmhaputra Foredeep in front of the rising Himalayan Mountain belt.

Pre-Quaternary (more than 570 million years to 2 million years before the present age) geology of West Bengal can be described through the exposures of Precambrian, Palaeozoic, Mesozoic and Tertiary rocks bordering the western and northern fringes of West Bengal. Whereas the western part of West Bengal forms the eastern edge of the Precambrian shield and has a stable cratonic mass, the northern end of West Bengal is a part of the orogenic belt of active tectonism representing the outer and lesser Himalayas.

Quaternary (2 million years ago to the present day) geology of West Bengal is characterised by the shelf zone to the west of the Bhagirathi-Hughly, the Himalayan Foredeep zone to the north of Ganga-Padma and the Mid-Basinal zone to the east of the Bhagirathi-Hughly. In the shelf zone to the west of the Bhagirathi-Hughly, the probable Neogene-Quaternary boundary may be placed between the Mio-Pliocene Bhairab Banki formation and the Pleistocene Lalgarh Formation in the Kasai basin of Midnapur and Bankura districts. The Lalgarh Formation has been classified into lower and upper units. The lower Lalgarh Formation that occurs at the higher level represents the primary laterite developed over the Pleistocene boulder conglomerate. It consists of rounded pebbles, cobbles, and boulders of Precambrian rocks, Tertiary laterite, Mio-Pliocene (24 million years to 2 million years before the present age) fossil wood and also pellets of white shale of Bhairab-Banki Formation. The Upper Lalgarh Formation consists of reworked and redeposited sediments of the Lower Lalgarh Formation and contains vertebrate fossils of the Middle to the Upper Pleistocene (2 million years to 0.1 million years before present) age.

The oldest alluvial terrace sediments developed above the Lalgarh formation. These sediments are known as the Sijua Formation and occur extensively in Midnapur, Bankura, Burdwan, Birbhum and Murshidabad districts. The age of these sediments is early Holocene though deposition of its basal part might have started in the Late Pleistocene period. There is another sequence of alluvial terrace known as the Daintikiri/ Panskura formation of the Middle Holocene age. These sediments are spread over Midnapur, Hooghli, Howrah, Bankura, Burdwan, Birbhum, Murshidabad and Malda districts. The Himalayan foredeep zone to the north of the Ganga-Padma plain consists of a number of distinct generations of fan deposits. These are the Samsing-Thaljhora formation (equivalent to the Lalgarh Formation of the self Zone) which occurs in the foothills of Darjeling district at an altitude of 600m to 280m, the Matiali-Chalsa Formation (equivalent to the Sijua Formation of the same Zone) which occurs at 80-280m altitude in Darjeeling and Jalpaiguri districts and the Baikanthapur Formation (equivalent to the Daintikiri/ Panskura Formation of the same Zone) which occurs at altitudes of 180m to 30m in the district of Darjeeling, Jalpaiguri, Coochbehar, and West Dinajpur.

The mid-Basinal zone to the east of the Bhagirathi-Hooghly consists of low-lying alluvial plains comprising deltaic sediments of three generations: 1) the upper most matured deltaic and estuarine sediments cover Murshidabad, Nadia, and North 24-Parganas districts of the middle Holocene age and are known as the Dum Dum formation; 2) the intermediate matured deltaic and estuarine sediments of the late Holocene age are developed at a lower surface and are found to occur on both sides of Midnapur districts) and are recognised as Calcutta Formation; and 3) the lower most deltaic sediments of late Holocene to recent age found to occur in south 24-Parganas district and are known as Sundarban formation. Among the above formations, Prehostoric sites and artifacts are associated with the formations of Pleistocene to early Holocene age of different zones.

The Bangladesh portion of the Bengal basin can be characterized by: 1) the tertiary hills, which include the hills of Chittagong and the Chittagong Hill tracts and Sylhet, all marked by deeply weathered lateritic red soil; 2) the Pleistocene lateritic terraces which include the Barind (North Bengal), the Madhupur tract (Tangail, Narshingdi, and Gajipur parts of Mymensingh and Dhaka), the Lalmai Hills and some higher grounds in Sylhet; 3) the flood plain, mainly north and east of the Padma river, which includes the Sylhet basin, the Faridpur trough and the piedmont alluvial plain of North Bengal, where the soils are little weathered gray silt and clays and where locally there are near surface peats; 4) the deltaic plain which covers the area between the Ganges and the bay of bengal, and which passes southwards into the sundarbans - the low tidal area of Khulna and Patuakhali; and 5) the South coastal plain which includes the low coastal area extending from Noakhali to the south of Cox's Bazar. All the reported prehistoric records of Bangladesh are associated with the Lalmai hills and the higher areas of Sylhet, Habiganj, and Chittagong and Madhupur Tract.

In order to understand the prehistoric situation of Bangladesh, it is essential to have a glimpse of the prehistoric situation of the surrounding regions of Bangladesh, especially Assam, Arunachal Pradesh, Manipur, Nagaland, Meghalaya, Mizoram, Tripura, Bihar, Orissa, West Bengal and Myanmar. These have been comparatively fewer prehistoric explorations around the present territory of Bangladesh and finds from Assam, Bihar and Bengal have been sporadic in nature.

Systemic investigations for the prehistoric and protohistoric evidence in northeast India (Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland and Tripura) began in the 60's of the twentieth century. A team led by HD Sankalia carried explorations in the Langthing and Mahur river valleys of North Cachar Hills of Assam and discovered the stratified neolithic site of Daojali Hading. Excavation in the site yielded cultural materials consisting of polished stone tool industry, a ceramic industry, and a host of household appliances such as corn grinders, stone rubbers, and mullers. The Department of Anthropology of Gauhati University has been carrying out explorations in the river valleys of Ganol, Rongram and Simsang of the Garo Hills. They have identified a large number of Stone Age sites which have cultural materials relating to all phases of the Stone Age. Out of them Selbagiri, Thebrongri, Mismagiri and Rongram Alagiri of this area have been tested by trial excavation.

In the sites of Thebrongri, Mokbol Abri and Mishimagiri II huge quantities of cores, waste flakes, and unfinished tools, a few finished hand axes, cleavers and large discoids made on dolerite have been unearthed. The Mishimagiri III and Didami sites have yielded large number of fluted cores in association with huge quantities of blade flakes and a variety of blade tools. The palaeolithic finds of the Garo Hills represent another interesting cultural tradition called the eastern pebble tradition. In the Simsang-Nangal valley at Nangalbibra, these pebble and flake tools seemed to have been made on dolerite and chert pebbles. Microliths were found on the surfaces of sites at Selbagiri and Thebongiri. Later, a trial excavation at Selbagiri, which is located on the ancient terrace of the Rongram valley near the village of Selbagiri, revealed that there occurred a clear microlithic horizon below the Neolithic level. The Neolithic level has yielded both ground and chipped axes and plain hand-made grey pottery ware.

The excavation at Rongram Alagiri revealed two cultural levels: (1) the Neolithic on the top characterised by the presence of rounded butt axes and the absence of shouldered axes; and (2) the Hoabinhian below the Neolithic level characterised by pebble axes and choppers in association with heavy stone pounders without pottery. Excavation at the Chitra Abri (2km southwest of the Renchangiri village and on the left bank of the Rongram river) site unearthed two broad groups of Stone Age industries viz (1) the flake blade industry and (2) the Neolithic ground-stone axe industry associated with hand made pottery. The distinguishing features of the Chitra Abri Neolithic assemblage are that it contains a significant amount of shouldered celts and all tools of this industry are made on Dolerite.

A team from the University of Dibrugarh has carried excavations at a Neolithic site at Sarutaru, in Kamrup district of Assam. BP Bopardikar of the Prehistory Branch of the Archaeological Survey of India has explored the Dephabum area in Luhit district of Arunachal Pradesh and has discovered stone tools of the Palaeolithic tradition and the Neolithic tradition. O.K. Singh of the Archaeological Survey of Manipur State has carried out exploration in different parts of the state and has discovered a number of limestone caves near Ukhrul. He dug a trench in cave No 3 and unearthed both stone and bone tools. However, from Mizoram, only one stone axe has been found so far. It is a large and thin axe made on slate. The prehistory of Nagaland is known only through a surface collection of stone tools found mainly in the central part of the state known as the Sema and Lhota territories. The principal raw material used for making stone tools is a kind of olive green fine-grained rock called diorite/ serpentine. Other rarely used raw materials are shale, sandstone and schist. Typologically, tools belong to two groups: (1) the shouldered/tanged celts and (2) the triangular/ pointed butt axes.

In Tripura, the south-easternmost border state in North-east India that overlooks the deltaic plains of Bangladesh, N R Ramesh of the Geological Survey of India has located over half a dozen implementiferous sites in the Khowai and Haora valleys. As many as 700 stone implements have been collected from locations around Teliamura, Jirania, Mohanpur, Bishalgarh and Agartala. The most consequential feature of Tripura prehistory is that instead of stone, as evidenced in other parts of India, silicified fossil wood, which is locally available, was used for making tools. The tools have been grouped into: (a) Pre-neolithic assemblage without polished axes but having typological affinity with Neolithic tools and (b) Neolithic assemblage dominated by polished axes. The Pre-Neolithic assemblage belongs to the Late Pleistocene (?) age (much younger than 35000 YBP and older than 3500 YBP as indicated by the dated stratigraphic records of the older and younger terrace deposits). In its totality, the artefact assemblage has a close resemblance to the Anyathian and Neolithic tools that have been reported from the Irrawaddy valley of Burma.

In the Chhotanagpur plateau implements of the Lower Palaeolithic age have been discovered from different locations of the districts of Palamau, Ranchi, Hazaribagh, Monghyr, Gaya, Purulia and Singhbhum. Hardly any lower and middle Palaeolithic tools have been reported in a proper stratigraphic context in the Palamau district. However, DK Chakrabarty has reported a few artefacts in the secondary context. He and AK Gosh have reported about 7 upper Palaeolithic (industries comprising of points, blades, burins, knives and awls made on fine-grained quartz, crystal quartz and chert) tools. The Hazaribagh-Giridih prehistoric situation is still elusive; four lower and four middle Palaeolithic and a number of upper Palaeolithic occurrences have been reported. These sites contain flakes, hand axes, scrapers, borers, points, etc made on quartz. Vidula Jayaswal has reported 30 specimens discovered in 9 different locations of Ranchi district. The assemblage comprises chopping tools, handaxes, scrapers, flakes, cores cleavers, etc. AK Gosh has explored certain parts of the district in the upper Subarnarekha valley and has reported finding a number of sites.

Dilip K Chakrabarty has also reported a number of lithic occurrences in this district. Here Stone Age industries, mainly comprising upper Palaeolithic assemblage and microliths but with very few lower Palaeolithic elements have been found. The artefacts discovered were generally made on quartz and grey black chert was used in some cases. Scholars have identified about 40 prehistoric locations in the Shingbhum district. Here lower Palaeolithic implements (hand axes, chopper, chopping tools, cleaver discoid core, etc) were made on quartzite, middle (borer, point, various scraper, retouched flake etc) and upper Palaeoliths (blade, retouched blade, burin, point etc) were made on fine grained quartzite. Dilip Chakrabarty succeeded in discovering sporadic occurrences of lower Palaeolithic tools in the rolling topography of the western section of Santal Pargana district. He has also ascertained the presence of widespread occurrence of an upper Palaeolithic industry in the Damin and Rajmahal area. The Damin industry is characterised by overwhelming dominant elements of scrapers of various kinds of retouched flakes and cores and also by an incipient blade industry along with microliths including fluted cores. Chakrabarty has claimed that this industry is an upper Palaeolithic one with a strong regional character.

In addition, at Paisra in the Kharagpur range near Munger in Bihar, evidence of Mesolithic habitation has been revealed, where the occupational remains are to be found 65-90 cm below the earth surface. About 105sq m of this floor has been exposed in excavations and 26 finished tools (lunates, side scrappers, backed blades, gravette point etc) were found as well as numerous fireplaces. The calibrated range of Radio-carbon date of this site is 6377 to 6067 BC. No authentic Neolithic site has yet been discovered in the Chhotanagpur plateau. But in the alluvial plains of northern Bihar a number of sites (Chirand, Senur, Taradih etc) containing neolithic level have been attested.

West Bengal-Prehistoric and Protohistoric Situation Geographically, West Bengal (21BA38' to 27°10'N, 85°50' to 89°5'E) is characterised by a host of panoramic landscapes ranging from the Himalayas in the north, the Bay of Bengal on the south, the weathered hills of the west, and the flood plain in the east. These four regions represent four distinct ecological zones. The total area of the state is 87,616sq km. Evidence of the Palaeolithic culture of West Bengal has been reported from the south-western part of the state. Comprising the districts of Bankura, Purulia, south-west Midnapur, Birbhum and Burdwan, this part of the state is a vast undulating stretch of land intersected and drained by a number of rivers (Kasai or Kangsabati, Suvarnarekha, Mayurakshi, Ajay, Damodar, Gandesawari, etc) and their tributaries. Palaeolithic sites are mainly located above the 50m contour line in various contexts such as hill slopes, foothills, elevated tracts, and on riverbanks.

There are 162 lower Palaeolithic sites in this state. The majority of the lower Palaeolithic sites have been reported from Radh plain and are located on the foothills, valley slopes, and riverbanks. The tools in this region were mainly made on pebbles of quartz and quartzite. At Egara Mail in Burdwan district and at Tarapheni Reservoir Bridge in Midnapur district, tools fashioned on fossil wood have been found.

The lower palaeoliths in this region are handaxes, cleavers, chopper-chopping tools, different types of scrapers, retouched blades, flakes, cores etc. The geological horizons of the lower palaeolithic industry in this state was either lower gravel bed or secondary laterite/detrital lateritic conglomerate. Some important sites are: Egara Mail (Burdwan), Parihati, Mohanpur, Satbati, Tarapheni reservor bridge (all in Midnapur), Nakbindhi, Patina, Jibdharipur (Birbhum), Jagannathpur, Ganganir Math etc.

A total of 41 sites of middle Palaeolithic period have been reported from West Bengal. Of these 19 are located in Bankura, 13 in Midnapur, and four each in Birbhum and Burdwan districts. The presence of flake tools and use of Levallois technique mark the middle Palaeoliths of this region. The main artefact types are scrapers, points and borers, and are made mainly on quartz and quartzite. The important sites are Kanapahar, Dabha, (in Purulia district), Dhankura in Bankura district, and Parihati, Mohanpur Satbati, etc in Midnapur district.

A total of 10 upper Palaeolithic sites have been found in West Bengal. Out of them, five are in Midnapur District, four in Bankura district, and one in Burdwan district. Of these Kattara (22BA39°N 86BA41°E) of Midnapur district was excavated by A Datta and D Ray in 1989. Upper palaeoliths of West Bengal are characterised by tanged points, backed blades, burin spear heads etc and were made on green quartzite, chert, quartz, sandstone etc.

In West Bengal, 208-microlithic sites have been reported. Of these, 86 are located in Bankura, 61 in Midnapur, 36 in Birbhum, 23 in Burdwan, and 1 each in Murshidabad and 24-Pargana districts. Only three sites, namely Birbhanpur in Burdwan district, Paruldanga in Birbhum district and Chamargora in Midnapur district have been excavated. Mesolithic sites of this region have yielded lithic assemblage of both non-geometric and geometric types. Artefacts include lunettes, points, scrapers, borers, burins, cores etc. and were made on chart, chalcedony, quartz, quartzite, fossil wood etc.

The issue of stratigraphy, as proposed by Dilip Chakrabarty, is represented by a detrital lateritic conglomerate, which was successively underlain by mottled clay, bedrock, and overlain by sandy deposit. Microliths occur on the surface of the lateritic conglomerate and in the sandy deposit on it. Lower Palaeoliths occur towards the junction of the conglomerate and the mottled clay, whereas Middle Palaeoliths occur higher in the profile. He argued that the Upper Palaeoliths occur in the upper most layer of the conglomerate. The geological stratigraphy of the area and the archaeological stratigraphy of different localities remain unrelated. Moreover, datable materials for dating absolutely the different horizons of Palaeolithic and Mesolithic culture are not available. So the chronology of these cultures in West Bengal and Chhotanagpur region remain uncertain.

A total of 84 Neolithic sites have been identified in West Bengal. The nature and distribution of Neolithic records in West Bengal suggest two focal areas of Neolithic culture with opposite patterns of developments. They are the Himalayan foothills (comprising Kalimpong and adjacent Sikkim State) and the plateau fringe area (comprising the districts of Midnapur, Bankura, Purulia, Burdwan and Birbhum). In the plateau fringe area, Neolithic sites are found all along on the riverbanks or near rivers. But in the Himalayan foothill region, sites are found along the hill terraces. Neolithic tools with a distinct ceramic industry (grey and pale redware, sometimes with cord impression) characterise the Neolithic culture of the Plateau fringe area, whereas Himalayan foothill Neolithic culture is characterised by Neolithic tools without ceramics. There is another region known as the Western Plains in West Bengal where Neolithic records have been found in association with the later Chalcolithic culture or in a mixed up condition.

Neolithic sites in the plateau fringe area are named on the basis of their occurrences in river valleys such as the Suvarnarekha Complex (contains 23 occurrences: Bheduahari, Pandapata, Tilkamati. Ghorapincha, Kalayasal, etc), the Kasai Complex (contains 22 occurrences: Organda, Palasdanga, Laljal, Kattara I and II, Lalgarh etc) and the Gandheshawari complex (contains 14 occurrences: Banasuria, Simulbaria, Pareshnath etc). Major tool types of the occurrences of Subarnarekha complex are celts, adzes, splayed axes, shouldered celts, chisels etc. In Kasai complex, predominant tool types are different types of celts, ringstones, adzes, etc. The Gandeshwari complex contains predominantly rounded butt celts but there is a complete absence of shouldered tools here. In the western region of West Bengal, Bharatpur and pandu rajar dhibi in Burdwan, Dihar in Bankura, and Tamluk in Midnapur are sites that have yielded Neolithic assemblage at the base level or from surface along with Chalcolithic elements, suggesting the presence of a distinct Neo-chalcolithic phase in this region.

Large-scale excavations at Pandu Rajar Dhibi carried out the Directorate of Archaeology, West Bengal, reveals a cultural assemblage of four distinct periods. Periods I and II belong to the Neo-Chalcolithic phase, Period III belongs to the Iron age, and Period IV belongs to the early historic and mediaeval age, although it overlaps with the preceding period. In 1975, excavations at Tamluk yielded a charred deposit containing Chalcolithic assemblages such as the black-and-red ware in characteristic shapes, tiny Neolithic celts, and a variety of bone implements. Chalcolithic culture with its neolithic elements was succeeded by iron-using people. However, the black-and-red ware of degenerated variety continues, while in upper levels NBPW and associated black slipped ware have been found.

Prehistoric explorations in Bangladesh J Coggin Brown reported a prehistoric celt from Shitakunda of Chittagong in his Prehistoric Antiquities of India Preserved in the Indian Museum, Calcutta in 1917. rakhaldas bandyopadhyaya mentioned the discovery of a fossilwood shouldered celt in the Sitakunda hill of Chittagong as early as 1886. In 1958 Dyson, a US citizen, handed over a stone implement found accidentally on the surface at Rangamati district of Chittagong.

A prehistoric implement, which is currently displayed as a hand axe in the National Museum, Dhaka, was collected by the Museum in 1963 from Amjadhata Union of Chhagalnaiya upazila near its border with Ramgarh in Chittogong Hill Tracts. In 1979, Nazimuddin Ahmed reported the discovery of a few Neolithic stone axes together with some unfinished specimens and raw materials in the eighth-tenth century AD levels of the Ananda Vihara excavations (1976-78) at mainamati. Nine specimens of these are on display in the site museum at Mainamati.

Md Habibulla Pathan (1395 BS) reported some neolithic celts, shouldered axes, and triangular axes from the wari-bateshwar area of Narsingdi district.

In 1989, during their exploration in the Lalmai-Mainamati region of Comilla district, DK Chakrabarti's team recovered 234 prehistoric artefacts of various types made on fossilwood (silcified) from eleven occurrences in the south and south-east portions of the Lalmai hills. In 1991, the Directorate of Archaeology, Bangladesh, conducted another systematic investigation in the Lalmai hills. They recovered a total of 240 prehistoric implements made on silcified fossil wood from four occurrences of this hill range. In 1998 two students of the Department of Archaeology, jahangirnagar university, recovered a typical Acheulian hand axe from the area between Maiddher Mura and Membarer khil and some blades, bladelets and flakes from Dhanmura while they were exploring the Lalmai hills.

In 1997, a team from Jahangirnagar University came across an occurrence of prehistoric implements in Chaklapunji Tea State of Chunarughat in Habiganj district. They also recovered some artefacts made on silcified fossil wood.

Prehistoric Data from Bangladesh Regions which have yielded prehistoric artifacts in Bangladesh are the Lalmai hills near Comilla, Chaklapunji Tea Garden of Chunarughat in the Habiganj district of Sylhet, Sitakunda and Rangamati of the Chittagong region, and the Wari-Bateshwar of Narshingdi district. These regions of Bangladesh contain both Pleistocene deposits and suitable raw materials. In the Sitakunda area extensive occurrences of pebbles have been noticed, but it could not be ascertained whether such pebbles were used for the making of prehistoric tools in this region. But in the Wari-Bateshwar, several Neolithic tools such as celts, shouldered axes, etc made on sand stone, silt stone and fossil wood have been found, though their raw materials are not locally available. The most suitable rock in this region is fossil wood and this is what was used as the raw material of the prehistoric industry of the Lalmai hills, Chaklapunji tea garden and most of the prehistoric tools, reported sporadically.

Pre-neolithic Tool Types from Lalmai Hills (After MM Hassan) Courtesy: Manjurul Hassan

These fossil woods were fossilised by petrification, a slow process of fossilisation whereby organic matter was converted into a stony substance by the infiltration of water containing dissolved inorganic matter (eg calcium carbonate, silica, calcite, limonite, pyrite, etc) which replaced the original organic materials, although retaining the structure. Three types of petrified fossil wood were used in making the artifacts of Lalmaian industry. The first type is blackish in colour, in hardness between 8 and 9 in mho scale, and with a specific gravity of between 2.7 and 2.5 defines the first type. The second type is characterised by light blackish to light brown in colour, in hardness between 7 and 8 in mho scale and with a specific gravity of between 2.5 and 2.4. The third type is light brown to yellowish in colour, in hardness between 4 and 5, and with a specific gravity of between 2.4 to 2.3. The Maximum number of artifacts of Lalmaian industry was made on the second type of fossil wood.

The prehistoric archaeological sites of Bangladesh have been found wholly on the older alluvium of the Pleistocene epoch. The alluvium exposed in the Pleistocene Terrace area in general, and in the Lalmai hills in particular, may be classified into three units according to their lithological characteristics and depositional environment. These are: (a) Dupi Tila formation (yellowish unconsolidated sands with a few shale beds and containing gravels at depth) of the Pliocene epoch, (b) Madhupur clay (overlying the Dupi Tila formation and mainly reddish brown and yellowish brown clay and sandy clay, with occasional nodules of iron concretions.) of the Pleistocene epoch, and (c) alluvium formation (grey silty clay) of recent times.

Neolithic Tool Types from Lalmai Hills (After MM Hassan) Courtesy: Manjurul Hassan

The Lalmai-Mainamati hill complex is about 8 km long and 4.8 km wide at its maximum and constitutes an uplifted north-south elongated block surrounded by the Lalmai terrace with a few localised faults. The average height of the spurs is about 12m, with individual spurs rising up to a height of 30m or more. The landscape is basically a rolling upland interspersed by depressions between the ridges. It would appear that the major part of the Lalmai hills has been blanketed by Madhupur clay formation. Erosion has removed part of it. The vegetation cover of the area is severely denuded by the on going cultural system. However, its early traces still survive in the form of xal trees, bamboo groves, mango and jackfruit trees etc. During historic periods, tribal groups probably used the area for slash-and-burn agriculture. A tribal group known as Tipras used to live in this area. Now farmers who have settled in this zone use the tops and slope of the spurs for planting vegetables, whereas the depressions between them are used for the cultivation of paddy.

Pre-neolithic Tool Types from Lalmai Hills (After MM Hassan) Courtesy: Manjurul Hassan

The prehistoric site of Chaklapunji tea garden, near Chandirmazar of Chunarughat, has also revealed a significant number of prehistoric tools from the bed of a small ephemeral stream (water remains here only for a few hours after rainfall) known as Balu nadi (Balu River). Angularity and freshness of the fossil wood artefacts suggest that they did not come from a great distance and probably came from nearby hillocks. Typologically, technologically, and morphometrically, the artefacts are more or less the same as those found in the Lalmai area. The Fossil wood assemblages of Lalmai and Chaklapunji can be classified into two groups: (1) Pre-neolithic assemblages without polished tools (hand axes, cleavers, scrapers, chopping tools, points etc); and (2) Neolithic assemblages (hand adzes, polished celts, awls etc). Shafiqul Alam of the former Directorate of Archaeology, Bangladesh believes that earthen potsherds are associated with the last group of assemblages.

It should be mentioned here that similar pre-historic finds were reported from the Haora and Khoai valleys of Tripura State, India. The Anyathian and Neolithic tools from Irrawaddy Valley of Burma bear close resemblance to the finds of Lalmai hills and Chaklapunji of Bangladesh. The technological and typological similarities and distribution of fossil wood assemblages in considerable high frequency throughout the eastern and southeastern part of Bangladesh, Haora, and Khowai valley of Tripura, and Irrawaddy valley of Burma (Myanmar) suggest a regional prehistoric cultural tradition in this region. [Syed Mohammad Kamrul Ahsan]