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No. 85: Jan-Feb 1993

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Clams Before Columbus

"Zoologists and geologists agree that specimens of Mya arenaria (the American soft-shell clam) from the Holocene found in Europe first appeared in the sixteenth century, after the voyage of Columbus. But we have dated a sample from the Kattegat region on the east coast of the Skaw in northern Jutland, Denmark, that predates Columbus's voyage. This result implies that contact between America and Europe existed before the sixteenth century."

In fact, one sample of the American soft-shell clam was carbon-dated by the authors of the above paragraph at 1245-12951 standard deviation. This particular shell was discovered in the sand barrier farthest from the Danish coast. Since it seems highly unlikely that the larvae of the American clam could have swam across the Atlantic, the authors wonder if the Vikings might have carried them home. (Petersen, K.S., et al; "Clams before Columbus," Nature, 359:679, 1992.)

Comment. Certainly the Vikings might have consumed these clams on their voyages to the New World, but why would they or any other explorer carry live clams or their larvae back to the Old World? Or was the transfer accidental in ships' ballast?

From Science Frontiers #85, JAN-FEB 1993. 1993-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987