Research Article| October 01, 1963 Pelecypods as Stratigraphic Guides in the Appalachian Upper Devonian A. LEE McALESTER A. LEE McALESTER Peabody Museum, Yale University, New Haven, Conn Search for other works by this author on: GSW Google Scholar Author and Article Information A. LEE McALESTER Peabody Museum, Yale University, New Haven, Conn Publisher: Geological Society of America Received: 06 May 1963 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1963, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1963) 74 (10): 1209–1224. https://doi.org/10.1130/0016-7606(1963)74[1209:PASGIT]2.0.CO;2 Article history Received: 06 May 1963 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation A. LEE McALESTER; Pelecypods as Stratigraphic Guides in the Appalachian Upper Devonian. GSA Bulletin 1963;; 74 (10): 1209–1224. doi: https://doi.org/10.1130/0016-7606(1963)74[1209:PASGIT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A recent taxonomic revision of the prolific pelecypod faunas occurring in the type region of the Chemung Stage has provided basic data for biostratigraphic interpretations in Upper Devonian marine rocks of the Appalachian region. Application of the concepts of population systematics to the Chemung pelecypods has reduced by 70 per cent the number of species names formerly applied to the fauna. The taxonomic revision has therefore greatly simplified the practical problem of identifying pelecypod species in these rocks. Many species have restricted time ranges. More than one third of the species have been found in only a single stage, and more than two thirds are known from only one or two of the four stages of the Appalachian Upper Devonian. In addition, a quantitative comparison of species abundance within the Chemung Stage reveals significant differences in species distribution at different Stratigraphic horizons. The degree of Stratigraphic restriction of the Chemung pelecypods compares favorably with that found in other stratigraphically valuable fossil groups. This indicates that these abundant and widely distributed pelecypod faunas may prove useful in correlating Upper Devonian strata throughout the Appalachian region.Most Chemung pelecypod species show little or no evidence of evolutionary change throughout their range of occurrence in the Appalachian Devonian. This suggests that the Stratigraphic restriction observed in many species was ultimately caused by environmental variation and not by evolutionary modification. A comparison of the observed time ranges of the Chemung species with ranges reported for late Cenozoic pelecypods indicates that the Chemung Stage represented too short a time (approximately 5 m. y.) to encompass significant evolutionary change in the pelecypod faunas. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.