 An archaeological site on the Harrison Mills side of the bay, the Scowlitz Mounds, also known as the Fraser Valley Pyramids, is under investigation by Simon Fraser University and the Scowlitz First Nation and represent an unusual period in the anthropological and cultural history of the Fraser Valley.The Scowlitz are Halqemeylem-speaking and are part of the cultural group, while the Sts'ailes (Chehalis) identify themselves separately and speak a dialect of Halqemeylem that has similarities with the Lower Lillooet River dialect of St'at'imcets (Ucwalmicwts).The dialect spoken by the Sts'Ailes, whose name means "beating heart", includes the word "sesqac", which is the source of the English word "sasquatch".