From MARK McMENAMIN
The article ‘Piecing together the Pacific’ by Garry Davidson (18 January)
mentions that the 750 to 700 million year old Precambrian supercontinent
is unnamed. This is not so; Dianna McMenamin and I named it Rodinia in our
book The Emergence of Animals: The Cambrian Breakthrough (1990, Columbia
University Press).
The Moores-Dalziel reconstruction of Rodinia is interesting, but fails
to explain the similarities of several distinctive Precambrian fossils (members
of the Ediacaran biota) occurring in Australia and Baltica but nowhere else.
Australia and Baltica are positioned at opposite ends of Rodinia in the
Moores-Dalziel reconstruction. Considering the inconsistencies with the
Moores-Dalziel reconstruction cited by Davidson concerning Cambrian trilobite
distributions on either side of the Pacific Ocean, plus the inconsistent
geographic separation of Australian Baltican fossils, there is still some
work to be done to correctly complete the Rodinia jigsaw puzzle.
Mark McMenamin Mount Holyoke College Massachusetts, US
