In addition to the works mentioned by Andrew on the Chesapecten I would
like to offer the following two references

WH Dall. 1898. Contributions to the Tertiary Fauna of Florida.
Transactions of the Wagner Free Institute of Science. Vol. 3, Part 4.
  Description of Pecten madisonius var. sayanus new variety
This is listed as a Chesapecten now.

RN Benson, editor. 1998. Geology and Paleontology of the Lower Miocene
Pollack Farm Fossil Site, Delaware. Delaware Geological Survey Special
Publication 21.
  Illustrates Chesapecten sayana (Dall, 1898) found in Delaware as well as
several other Chesapecten species.  This book can be found on-line at the
Delaware Geol. Survey webpage...sorry I don't have the URL handy.

Charlie
******************************************************************************
Charlie Sturm, Jr
Research Associate - Section of Invertebrate Zoology
                     Carnegie Museum of Natural History, Pittsburgh, PA
Assistant Professor - Family Medicine

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