Vol. 248, Issue 12, 1950December 01, 1950 EDT
The Irvingella Major (“Ptychopleurites”) Faunizone of the Upper Cambrian
The Irvingella Major (“Ptychopleurites”) Faunizone of the Upper Cambrian
James Lee Wilson, Edward Arthur Frederickson,
Wilson, J. L., & Frederickson, E. A. (1950). The Irvingella major (“Ptychopleurites”) faunizone of the Upper Cambrian. American Journal of Science, 248(12), 891–902. https://doi.org/10.2475/ajs.248.12.891