Table of Contents

Articles

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  Tetrapods of the Pennsylvanian nodules from Mazon Creek, Illinois

  Joseph Tracy Gregory

  American Journal of Science December 1950, 248 (12) 833-873; DOI: https://doi.org/10.2475/ajs.248.12.833
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  Marine crevasse fillings in the Lotbiniere region, Quebec

  Freleigh Fitz Osborne

  American Journal of Science December 1950, 248 (12) 874-890; DOI: https://doi.org/10.2475/ajs.248.12.874
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  The Irvingella major ("Ptychopleurites") faunizone of the Upper Cambrian

  James Lee Wilson and Edward Arthur Frederickson

  American Journal of Science December 1950, 248 (12) 891-902; DOI: https://doi.org/10.2475/ajs.248.12.891