Figure S3. Photos of typical sedimentary facies. (a) A core section of U2 from KHQ-14, showing the grey mud, typical of estuary deposit; (b) A profile of Xiasun archaeological site. The photo was taken during the excavation of the site, now refilled with sediments; (c) A portion of Xiasun profile, showing the sedimentary structure (twisted, contorted and convolute bedding); (d) A trench of the uppermost unit (U4) near Kuahuqiao site; (e) A portion of the same trench as (d), showing the sedimentary structure (squiggly, contorted and convolute bedding).