settlements. On a broader geographical context, Soanian culture is one of many different lithic cultures in Southeast Asia that are also abundantly available in Sub-Himalayas. Many unifacial flake tools belonging to the Hoabinhians are discovered near Soanian sites. These tools are also found throughout Nepal, South China, Taiwan and Australia. Another prominent lithic culture in the region belongs to the Acheulians, which are distinguished by the preference for bifacial tools. Post-Siwalik fluvial deposits Most of the post-Siwalik fluvial deposits today are mostly disintegrated, they currently lie above older decomposed sedimentary deposits. Some of them are covered in thick vegetation. These sites stand in contrast with remaining deposits that still stand today, forming basin like structures. Technologies Understandings for the technological development of Soanian tools have been limited due to most sites rarely comprising more than a few dozen artefacts. The technologies of Soanian culture are stone based and are often described as non-bifacial assemblages. These tools are categorized based on their unifacial nature with a singular flat surface. Soanian assemblages generally comprise varieties of choppers, discoids, scrapers, cores, and numerous flake type tools. These tools are mainly for heavy duty, but also have finer purposes as seen in some flake tools used for cutting. These tools are often manufactured on quartzite pebbles, cobbles, and occasionally from boulders. With Soanian technologies being limited, tools often remain similar in shape and sizes to their sourced materials. Soanian technological culture differ largely from other pre-historic culture in the region. Other cultures found in Siwalik like the Ancheulian are often described to be of bi-facial nature and focused on hand axes. The comparison between other culture of the same region has seen Soanian technology categorized as a continuation of archaic technology rather than Neolithic. This is due to Soanian culture often being isolated within the mountainous region away from plain populations who have access to more materials. Perspective of the singlular interval scholars Scholars of the singular interval period view the development of Soanian technology as a result of the deurbanization of the Harappan culture. This group was originally thought to have had large trading networks with intricate tools, as well as their own scripting system. However, due to the change of climate during the mid-Holocene epoch, many original settlements collapsed in search of water and have been reduced in size. The group began adopting tools that were more easily accessible. Excavation history and