Mega-highstand or megatsunami? Discussion of McMurtry et al. (Elevated marine deposits in Bermuda record a late Quaternary megatsunami: Sed. Geol. 200 (2007) 155–165)

Graded, sorted, rounded, and ponded marine sand and conglomerate deposited in caves and on an erosional terrace at + 20 m on Bermuda, previously interpreted as originating in a eustatic highstand of sea level during the middle Pleistocene, were reinterpreted by McMurtry et al. (2007) as the result of a great 20 m megatsunami at sea, propagating out across the North Atlantic from the Canary Islands, cresting, and rolling up and over the Bermuda platform. However, no middle Pleistocene tsunami deposits have been reported elsewhere on Bermuda or anywhere else around the North Atlantic rim. The tsunami origin is unsupportable whereas the available evidence unequivocally establishes a + 21 m eustatic sea level during the middle Pleistocene MIS 11 interglacial.