Palliseria (Middle Ordovician Gastropoda) from east-central Alaska and its stratigraphic and biogeographic significance

Abstract

Several unsilicified gastropod specimens were collected by John B. Mertie, Jr., on July 13, 1941, during a boat traverse along the Porcupine River of east-central Alaska. The specimens were originally deposited in the Ulrich (Cambrian and Ordovician) stratigraphic collections of the U.S. Geological Survey at the National Museum of Natural History, Washington, D.C. The collection contains one specimen of Palliseria and three specimens of Maclurites, all of which are broken from the limestone. Despite the lack of much of the shell material, they are easily identified as to genus. One specimen identified as Palliseria is particularly significant.