Latest Mississippian crinoid faunas of the Appalachian Basin, USA

Donald R. CHESNUT*
University of Kentucky, 228 MMRB, Lexington, KY 40506, USA; chesnut@uky.edu

Latest Mississippian (Late Viséan-Serpukhovian) crinoid faunas of the eastern United States are 
widely recognized as falling into three crinoid zones: Platycrinites penicillus zone of mid-Viséan 
age, Talarocrinus zone of Late Viséan age, and the Agassizocrinus cf A. conicus zone of latest 
Viséan through Serpukhovian age. The A. conicus-zone faunas of the Appalachian Basin, 
described here, are very rich in some places and numerous studies about them have been published 
since the mid-nineteenth century. Unfortunately, numerous species were erected based on minor 
variations in shape, and, in many cases, incomplete or poorly preserved specimens. This study 
attempts to refine and consolidate these species into a useful list. A literature survey of collections 
from the Hartselle Ss., Bangor Ls., and Pennington Fm. in northern Alabama (Southern 
Appalachian Basin) (largely from Burdick and Strimple, 1982) and my own studies of the Glen 
Dean Ls., Poppin Rock Ls., and the Paragon Fm. in Kentucky (Central Appalachian Basin) 
(Chesnut and Ettensohn, 1988) were used. Valid species recognized by this effort are: Subclass 
Inadunata, Zeacrinites wortheni, Bicidiocrinus wetherbyi, Tholocrinus spinosus, Linocrinus 
laurelensis, Dasciocrinus florialis, Cymbiocrinus grandis, Aenigmocrinus anomalus, 
Phacelocrinus longidactylus, Pulaskicrinus campanulus, Scammatocrinus pulaskiensis 
n. comb. (=Wetherbyocrinus), Culmicrinus vagulus, Aphelecrinus randolphensis, 
Anartiocrinus lyoni, Agassizocrinus conicus, Ramulocrinus milleri, Phanocrinus 
maniformis, P. parvaramus (= P. cavus, a junior synonym), Pentaramicrinus gracilis 
(=P. bangorensis, junior synonym), Eupachycrinus boydii; Subclass Flexibilia, 
Onychocrinus pulaskiensis, (=Bangor Ls. specimens of O. magnus,), Taxocrinus whitfieldi; 
Subclass Camarata, Pterotocrinus acutus (sensu Chesnut & Ettensohn, 1988), P. depressus, 
Dichocrinus girtyi, Hyrtanecrinus pentalobus, Strimplecrinus superstes, Camptocrinus 
cirrifer, Acrocrinus shumardi, Springeracrocrinus intermedius. 

Most of the identifiable dorsal cups and crowns come from thin limestone stringers in interbedded 
limestone and calcareous shale. Rapid burial is evident and probably caused by storms in a 
protected-marine setting. Massive limestones in the Bangor and Poppin Rock include calcarenites 
and calcirudites with grains composed of crinoid debris. Upper bedding surfaces show 
winnowed concentrations of crinoid debris including Pterotocrinus acutus wing plates and 
Agassizocrinus infrabasals, the only ossicles easily identified. These limestones formed in energetic 
zones above wave base, probably as bars or shoals. 

The most abundant identifiable crowns from the interbedded facies in Kentucky are, in descending 
order of abundance, Phanocrinus, Acrocrinus, Ramulocrinus, Pulaskicrinus, Aphelecrinus, 
Bicidiocrinus, and Taxocrinus. Phanocrinus was at least three times more abundant than any of 
the other crowns. I did not have abundance data for the Alabama specimens, but Phanocrinus 
also appears to be very abundant there as well.

Although crinoid ossicles have been recovered from higher stratigraphic levels in the Pennington 
and Paragon formations (Namurian A and B), identifiable specimens have not been reported 
except for tegmenal wing plates from unidentified Pterotocrinus species. These upper strata are 
understudied and warrant further field research.

References
Burdick, D. W., and Strimple, H. L., 1982, Genevievian and Chesterian crinoids of Alabama: 
Geological Survey of Alabama, Bulletin 121, 277 p.
Chesnut, D.R., and Ettensohn, F.R., 1988, Hombergian (Chesterian) echinoderm paleontology 
and paleoecology, south-central Kentucky: Bulletins of American Paleontology, v. 95, no. 330, 102 p.