Dear Harry It is indeed true that Cepaea hortensis is a pre-Viking native of Newfoundland and eastern Canada. The proof of this fact is that reliable carbon dates, that considerably pre-date the Viking era, exist for Cepaea hortensis collections (both paleontological and archaeological) from our region. However, the possibility that a number of post-Viking introductions of Cepaea hortensis may now be layered upon the original North American populations should not be ruled out. I would be surprised if such were NOT the case. ... I MUST NOW COMMENT on the rather dated quote attributed to Andrew Grebneff: "According to John Maunder (Newfoundland Museum, St. Johns) and Ron Noseworthy, not all of Newfoundland was glaciated during the Pleistocene/Holocene, and the colonies there survived" ... Current scientific thinking no longer substantially support this idea ... To be sure, a few high cliff faces in our western mountains may have remained above the glacial ice, and thus may have provided a few small precarious refugia for some small invertebrates (perhaps including some small molluscs? - the endemic Vallonia terranovae, which is found only in that region, MAY be a possible candidate?). However, even the tops of Newfoundland's Long Range Mountains (a northern extension of the Appalachian Mountain chain), long thought to have been ice-free even during major glacial events, have now been convincingly shown, using isotopic techniques, to have been well covered with non-flowing "cold-based" ice during those times. The more likely "refugial scenario" for the Newfoundland area seems to involve the "off-shore fishing banks", to the south of the Island of Newfoundland, which were clearly exposed above sea-level, and supposedly at least partially ice-free, during glacial times, when world sea-levels were known to have been more than 100 metres lower. Nonetheless, I should stress that the majority of modern-day glacial geologists seem to be of the opinion that these fishing banks, even including our very extensive Grand Bank, were almost entirely (although not necessarily completely) glaciated. Biologists, on the other hand, continue to come up with any number of reasons why these same fishing banks must have been at least substantially unglaciated. Perhaps the truth lies somewhere in between. In the meantime, the debate is FAR from being resolved. ... The land-bridge theory, however, can be safely debunked. There is no modern evidence for it! John Maunder ----- Original Message ----- From: Harry G. Lee To: [log in to unmask] Sent: Friday, November 27, 2009 3:09 PM Subject: Re: [CONCH-L] Grove snails Kentucky Dear Erick, Pilsbry (1939: 8) discussed the North American populations of Cepaea nemoralis (Linnaeus, 1758) at some length. That it originated in Europe is a near certainty based on its taxonomic affinities. Winkley (1904) seems to have made the first suggestion of its preglacial occurrence on this side of the Atlantic. Citing the peculiar distribution on many uninhabited islands poorly suited for maritime exploitation along the northeast American coast, he immediately dismissed transport by Norsemen and other Precolonial visitors. That Pleistocene glaciation covered much of the species' range in New England is indisputable, but these islands and some mainland glacier-free areas, e.g., Cape Ann and Cape Cod, MA could well have served as refugia. Further, Andrew Grebneff posted a comment to this forum a while back: "According to John Maunder (Newfoundland Museum, St. Johns) and Ron Noseworthy, not all of Newfoundland was glaciated during the Pleistocene/Holocene, and the colonies there survived." Pleistocene fossils and Precolumbian archaeological occurrences further bolster this argument. How did it get here? One theory has it that there was late Tertiary and Pleistocene uplift of the Arctic lands and a land bridge existed from Scotland to Iceland to Greenland to Labrador. Such a connection might also explain the European-Eastern North American distribution of other landsnails, e.g., Zoogenetes harpa, certain Euconulus spp., Pupilla muscorum, certain Vallonia spp., etc. Thus, not all snail taxa originating in Europe reached and became established in eastern North America through human agency. Most maybe, but not all. On the other hand, several eastern North American snails have been introduced into Europe, but that's another story and not one involving Cepaea. Harry ---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------