72 SOCIAL SCIENTIST tinned to persist and might have even increased later, even as Lower Assam absorbed more of the Turko-Afghan and Mughal impact; and Upper Assam, of the Tai impact. Upper Assam was, in any case, more dependent than Lower Assam on transplanted wet-rice cultivation during the 19th century and, in large parts of the former, its introduction had to await the arrival of the Ahoms.4 Incidentally, the presence of the wet rice technology in Assam even earlier, as indicated by such terms as Vrhadali and kshetra-ali in a copper-plate charters, was indeed taken note of in my chapter in the Cambridge Economic History. But the specific Ahom contribution is not negated thereby. The Ahom system of water control consisted of an elaborate network of dams and embankments, and the presence of anything of the kind on such a scale in pre-Ahom Assam is not suggested by available evidence. In my paper, I avoided generalizations on the basis of speculative reasoning and examined the problem of retardation only in the context of 'the southeastern part of Upper Assam', where the Ahoms had remained contained for the initial three centuries and for which area we have historical evidence. On their entry, they found the undulating terrain infested with forests and marshes and inhabited sparsely by several tribes of the Tibeto-Burman linguistic group. Apparently, at that initial stage, they did not come into meaningful contact with such areas as had earlier been substantially Indo-Aryanized. Hence, their isolation from the varnash-rama society was a prolonged affair, and their language and religion were retained even as late as the mid-17th century. Their buranjis (chronicles) bear this out with ample evidence. So do the extant ruins of the pre-13th century temple structures by their conspicuous absence in this habitat—the two contiguous districts of Sibsagar and Dibrugarh which are situated on the south bank of the Brahmaputra and are separated from Burma by the Patkai Range.5 It is also meaningful that none of the thirtytwo inscriptions consulted by Lahiri, was found in these districts. The Nagajari-Khanikargaon, Negheriting and Deopani finds only suggest that the Indo-Aryan thrust reached eastward up to the Jorhat district south of the Brahmaputra; while on the north bank, it enveloped the whole of the valley portion right up to the hills. All said, it may be concluded that a general retardation in the wake of the break-up of the central State ofKamarupa was not an impossibility. A definitive statement cannot however be made in this respect in the absence of adequate evidence. We can only point out to the ruination of the old cities and temple complexes, with no subsequent replacements^ and to the disappearance of the tradition of lithic architecture and sculpture that followed. There is some evidence of a sporadic issue of gold 4. This was shown with details in my "Ahom migration: its impact on the rice economy of medieval Assam", Artha- Vijnona (Pune), Vol. 9, June 1967. 5. The reference is to the new nomenclature of the districts following their latest reorganization in 1983.