Hand axes and other artifacts dated to early Paleolithic (1.8 million to 100,000 years ago) have been found in alluvial deposits along the Babai River in Dang Valley. Archeologists classify these as Acheulean, i.e. 'second-generation' toolmaking that succeeds the very oldest Olduwan. There are more numerous, less ancient archeological sites dating to the Upper Paleolithic/Late Pleistocene (about 50,000 to 10,000 years ago). These are also along the Babai, as well as in Deukhuri Valley (Rapti River) adjacent and south of Dang Valley.