The Sauk is a loosely defined term for the series of beds between the Precambrian Unconformity and a widespread unconformity (Knox and equivalent) in the Lower Ordovician. These sediments are presumed to represent the first wave of transgressive seas that washed across the contients following the Early Cambrian/Precambrian emergence of the North American Craton. This scenario may not represent an accurate description of the post-Precambrian events for a number of reasons.