Paul V. Heinrich is a geologist and archaeologist at Louisiana State University and described by some as a professional sceptic. He has an interesting website(a) where he discusses what he describes as the ‘wild side of geoarchaeology’ and elsewhere(b) attacks Charles Hapgood’s interpretation of ancient maps that seem to support the idea of an ice-free Antarctic.
He has also heavily criticised(c) Andrew Collins’ Gateway to Atlantis.
(a) http://www.intersurf.com/~chalcedony/wildside.shtml
(b) http://www.talkorigins.org/faqs/mom/oronteus.html
(c) http://www.hallofmaat.com/modules.php?name=Articles&file=article&sid=101

