Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
  Journal of Paleontology   Email Content Delivery
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Journal of Paleontology; March 2000; v. 74; no. 2; p. 247-253; DOI: 10.1666/0022-3360(2000)074<0247:SSIMB>2.0.CO;2
© 2000 Paleontological Society
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by BEAVER, H. H.
Right arrow Articles by PALATAS, M.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

SUMMIT STRUCTURES IN MISSISSIPPIAN BLASTOIDS

HAROLD H. BEAVER1, ALEXANDER J. FABIAN1 and MARK PALATAS1

1 Department of Geology, Baylor University, Waco, Texas 76798, 7016 Jackman Rd., Temperance, Michigan 48182, and 6307 Six Mile Lane, Louisville, Kentucky 40218

The Mississippian blastoid Pentremites Say, 1820, has three different types of summit structures. Type 1 summits are characterized by long slender plates and are present in upper Meramecian and lower-upper Chesterian beds occurring from Iowa to Alabama. Type 2 summits consist of a massive pyramidal summit composed of large toothlike plates. They occur in lower and middle Chesterian deposits located from Illinois to Kentucky. Type 3 summit structures differ greatly from Types 1 and 2, generally consisting of six to seven rectangular plates arched over each side of individual spiracles. They have been found only in middle Chesterian sediments of Kentucky. In all three types of summit structures, the plates covering the anal spiracle are the most numerous and have a specialized arrangement of plates. Some anal spiracles are covered by alternating small spikelike plates, while others display a distinct anal sac or moundlike structure consisting of many small polygonal plates. Type 2 summits have many similarities with Type 1, and may have been derived from it. Type 3 summits, however, are radically different in type of plates and in their arrangement; their origin is not known. Type 3 summits are very common in the middle Chesterian.






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by Paleontological Society