technological attributes of unifacially flaked cobble artifacts from Hoabinhian levels at Sai Yok Rockshelter, Kanchanaburi Province, west-central Thailand. His aim was to determine if Hoabinhian artefact types described by Colani could be defined as clusters of constantly recurring attributes such as length, width, thickness, mass, length-width ratio and cortex amount and distribution. Matthews found that Hoabinhian types did not exist and instead Hoabinhian artifacts reflect a continuous range of shapes and sizes. Following his archaeological excavation and surveys in Mae Hong Son Province, northwest Thailand, Chester Gorman (1970) proposed a more detailed definition as follows A generally unifacial flaked tool tradition made primarily on water rounded pebbles and large flakes detached from these pebbles Core tools ("Sumatraliths") made by complete flaking on one side of a pebble and grinding stones also made on rounded pebbles, usually in association with iron oxide A high incidence of used flakes (identified from edge-damage characteristics) Fairly similar assemblages of food remains including remains of extant shellfish, fish and small-to-medium-size mammals A cultural and ecological orientation to the use of rockshelters generally occurring near freshwater streams in an upland karstic topography (though Hoabinhian shell middens do indicate at least one other ecological orientation) Edge-grinding and cord-marked ceramics occurring, individually or together, in the upper layers of Hoabinhian deposits Gorman's work included a number of radiocarbon dates that confirmed the Holocene age of the Hoabinhian. Gorman's carbon-14 dates place Hoabinhian levels at spirit cave between 12,000 and 8000 BP, these levels have also produced cord-marked ceramics. The term was redefined in 1994 by archaeologists attending a conference held in Hanoi. At this conference Vietnamese archaeologists presented evidence of Hoabinhian artifacts dating to 17,000 years before the present. A vote was held where it was agreed that The concept of the Hoabinhian should be kept The best concept for "Hoabinhian" was an industry rather than a culture or techno-complex The chronology of the Hoabinhian industry dates is from "late-to-terminal Pleistocene to early-to-mid Holocene" The term "Sumatralith" should be retained The Hoabinhian Industry should be referred to as a "cobble" rather that a "pebble" tool industry The Hoabinhian should not be referred to as a "Mesolithic" phenomenon Pre-Hoabinian technology Hà Văn Tấn outlined in his paper his definition of a lithic technology that occurred before the Hoabinian. He found primitive flakes in stratigraphy below Hoabinian pebble tools across several sites in Southeast Asia which led him to name