Text S2. Kuahuqiao Site and Kuahuqiao Culture
Kuahuqiao Site (N30°08′42″, E120°13′02″), the type-site for the early Neolithic culture of the same name, is located 5 km south of Hangzhou City in Zhejiang Province (Fig.1 and Fig.S1), and lies at the boundary between the upland region to the south and west and the flat coastal plain around Hangzhou Bay to the east and north (Fig. 1). It is situated on the broad and flat flood plain of the Qiantangjiang River, gradually to the east joining the wetland environments of the coastal lowlands that are today largely given over to intensive paddy rice production. The archaeological site lies in a topographic shallow depression (Xianghu Lake, as is named today) between two lines of low hills (Fig. 1b). The shallow basin has been filled with sediments of estuary origin of early Holocene age, and capped by flood plain deposits of late Holocene age. The unconsolidated sediment sequence can reach up to 30 m below the surface at its deepest locality.
Much of the site was destroyed in the 1970s when the basal clays were dug out and used for brick-making. Parts of the remaining deposits were excavated for the first time in 1990, and again in 2001 and 2002, by the Zhejiang Provincial Institute of Cultural Relics and Archaeology. At the center of the surviving site the cultural layers are at their thickest, about 3 m, where a domestic settlement area was located, inferred from the distribution of the archaeological finds and primarily by the discovery of at least four wooden pile-dwellings during the 1990 excavation. The cultural layer at Kuahuqiao Site lies about 2–3 m below present-day OD. One of the most important preserved organic artefacts that testifies to the aquatic nature of the site is a wooden dugout canoe (Jiang and Liu, 2005) made of pine and over 5.5 m long that was recovered from near the northwest edge of the area that was excavated in 2001–02. Other well-preserved organic materials include wooden paddles and spades, ladders, worked timbers and adze handles, bamboo and bone implements, and fabric matting. The character of the wild rice harvested at Kuahuqiao Site remains the subject of debate (Pan, 2008; Fuller et al., 2008). While primarily a forager settlement exploiting the rich natural resources of the coastal marshes and hinterland, Kuahuqiao Site has an element of incipient rice cultivation within the resource base which, allied to the limited presence of domesticated pigs, the earliest food animal domesticate in China (Yuan et al., 2008), classifies it as very early Neolithic, supported by calibrated radiocarbon dates on the canoe of ca. 8,000 years ago (Jiang and Liu, 2005).