An Early Keticuloceras Zone Fauna from the Hale Formation in Northwestern Arkansas
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An Early Keticuloceras Zone Fauna From the Hale Formation in Northwestern Arkansas GEOLOGICAL SURVEY PROFESSIONAL PAPER 613-A An Early Reticuloceras Zone Fauna From the Hale Formation in Northwestern Arkansas By MACKENZIE GORDON, JR. CONTRIBUTIONS TO PALEONTOLOGY GEOLOGICAL SURVEY PROFESSIONAL PAPER 613-A Descriptions and illustrations of nine Lower P ennsy Ivanian goniatites from the lower part of the Morrow Series UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1968 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 45 cents (paper cover) CONTENTS Page Abstract _______________________________________________ Al Introduction ___________________________________________ 1 Stratigraphic setting ____________________________ _ - 1 Collecting localities _____ ___.__________________________ 3 Cane Hill Member ______. _____________________________ 3 Prairie Grove Member ____.________________________ 3 Register of localities _________-_-_______ __ _ 4 UA (University of Arkansas) localities ______________ _ 4 USGS (U.S. Geological Survey) localities ________________________- 4 Other localities _____________-_______________-_ - 5 Reticuloceras tiro Assemblage Zone ________________ _ 5 Descriptions of species _________-_______ _ - " References cited ____________- - __-__ ^" Index ____________________________________ 21 ILLUSTRATIONS [Plates follow index] PLATE 1. Syngastrioeeras, Bisatoceras, Hudsonoceras, Reticuloceras?, and Cymoceras. 2. Reticuloceras, Reticuloceras?, Branneroceras, and Stenopronorites. Page FIGURE 1. Index map showing collecting localities ________________________ -- _ A2 2. Syngastrioeeras globosum (Easton), cross sections and sutures ________ - _ 7 3. Bisatoceras paynei Gordon, external sutures of immature phragmocones __ _______ 8 4. Hudsonoceras moorei Quinn and Saunders, incomplete external sutures __-_____ 9 5. Cymoceras adonis n. sp., views of a paratype _________________ - 11 6. Cymoceras adonis n. sp., cross sections and sutures ______________ ______ 12 7. Reticuloceras tiro n. sp., cross sections and sutures ______________ 13 8. Reticuloceras? icaiiucrighti Quinn, cross sections and sutures ___________-_ 14 9. Reticuloceras? sp., external suture _________________________- - 16 10. Branneroceras semiretia (McCaleb), cross sections and suture _______ - 16 11. Branneroceras semiretia (McCaleb), suture of variant ___________ 17 12. Stenopronorites quinni n. sp., cross section and suture ____________ 17 in CONTRIBUTIONS TO PALEONTOLOGY AN EARLY RET1CULOCERAS ZONE FAUNA FROM THE HALE FORMATION IN NORTHWESTERN ARKANSAS BY MACKENZIE GORDON, JR. ABSTRACT STRATIGRAPHIC SETTING Nine species of goniatites occur in the upper part of the The fauna described in this paper occurs in Cane Hill Member and the basal part of the Prairie Grove roughly the ui:per half of the Cane Hill Member of Member of the Hale Formation. These species comprise the the Hale Formation and locally in the basal 1-3 earliest known cephalopod fauna from the Pennsylvanian feet of the Prairie Grove Member. Most of the an- rocks of North America. The Arkansas fossils occur in cal careous pebble conglomerate, calcareous sandstone, and sandy monoids were found in 1- or 2-foot thick claystone- limestone. The stratigraphic interval in which all nine spe pebble conglomerate beds, which are associated cies occur and to which five of them appear to be restricted with calcareous sandstone beds that occur as lenses constitutes the Reticuloceras tiro Zone. This zone can be in the typical shale of the Cane Hill Member. Shells correlated approximately with the lowest subdivision of the of some of the small species, particularly those of Lower Reticuloceras (I^a) Zone of northwestern Europe in cluding the British Isles. Reticuloceras, were generally found incorporated The species described and figured in this paper are: Syn- within claystone pebbles; many of the larger gastrioceras globosum (Easton), Bisatoceras paynei Gordon, shells which occur in the conglomerate matrix, are Hudsonoceras moorei Quinn and Saunders, Cymoceras adonis fragmental. These were death assemblages (than- n. sp., Reticuloceras tiro n. sp., Reticulocerasl wainwrighti atocoenoses), but reworking of the fossils is not Quinn, Reticulocerasl sp., Branneroceras semiretia (McCaleb), and Stenopronorites quinni n. sp. believed to have mixed species of very different ages, as these ammonoids were approximately con INTRODUCTION temporaneous inhabitants of the early Morrow Sea. No ammonoids have been found in the shale, The manuscript for the report on the Carbonif which is silty to finely arenaceous and singularly erous cephaloids of Arkansas (Gordon, 1964) was devoid of fossils. The shale is commonly riprje completed before cephalopods were found in the marked and contains many thin lenticules of fine Cane Hill Member of the Hale Formation. Most of grained sandstone that locally weather out as the Cane Hill cephalopod localities were discovered wafers an inch or two in diameter. by Professor J. H. Quinn, University of Kansas, At the locality near Cane Hill (fig. 1, loc. 1), this and his students; through their indefatigable efforts fauna occurs in a 6-foot thick unit consisting of a sizable collection, totaling some 600 specimens, sandy limestone and calcareous sandstone. The fcs- was amassed. In 1961, Profesor Quinn kindly siliferous unit is separated from the underlying loaned these fossils to the author. Additional sup Pitkin Limestone by a 6-foot bed of siltstone con plemental collections, totaling 145 specimens, from taining a basal few inches of shale and lenticular the University of Arkansas localities and from one bodies of pebble conglomerate. This lithology re new locality, were made by the writer in company sembles that of the Prairie Grove Member of the with Professor Quinn and his students or with Hale Formation, but L. G. Henbest (oral commun., members of the U.S. Geological Survey. All these 1961) traced the sandstone unit laterally and discov collections constitute the basis for the fossil de ered that it fingers into the typical platy shale lith scriptions given here. ology of the Cane Hill Member. Al A2 CONTRIBUTIONS TO PALEONTOLOGY 94°20' |j||f-Area of figure 1 WASHINGTON COUNTY 94°30 94°00' FIGURE 1. Collecting localities for Lower Pennsylvanian ammonoids. University of Arkansas and U.S. Geological Survey locality numbers for these sites are given in the register of localities (p. A4). AN EARLY RETICULOCERAS ZONE FAUNA A3 The combined lithologic and faunal evidence in Number collected dicates that the sediments of the Hale Formation Reticuloceras? wainwrighti Quinn _ .__ 6 Reticuloceras? sp _____________ ___ 1 were laid down in relatively shallow water, prob Branneroceras semiretia (McCaleb) .__ 2 ably in the shallow part of the neritic zone. Cymoceras adonis n. sp _________ .__ 7 Stenopronorites quinni n. sp ______ .__ 3 COLLECTING LOCALITIES Locality 4 of figure 1 is in the east wall of a The ammonoids described herein come from railroad cut in the town of Fayetteville. The fossils seven localities in the lower and middle parts of come from a limestone bed in the lower part of the Hale Formation. The localities, all in Washing the formation at this locality. However, as the ton County, Ark., are shown on the index map Cane Hill Member is transgressive and unconform- (fig. 1). Five of these are in the Cane Hill Member, ably overlies the Fayetteville Shale at this place, and two are probably in the Prairie Grove Member. it is possible that the lowest beds of the Cane Hill are absent here. The small collection consists of CANE HILL MEMBER the following species: At two of the five Cane Hill localities the ammo Number collected noids occur in pebble-conglomerate beds associated Syngastrioceras globosum (Easton) . ____ 1 with calcareous sandstone lenses within typical Reticuloceras tiro n. sp ______- ___ 1 Branneroceras semiretia (McCaleb) __ 3 shale and siltstone of the Cane Hill Member. These Cymoceras adonis n. sp _______. 5 two localities are at the Fayetteville Country Club and at Sequoyah (East) Mountain. At the Fayette Locality 1 of figure 1, in a quarry near Cane Hill, ville Country Club (fig. 1, loc. 3), the following has been discussed above. This locality also was species have been found. described and shown in a photograph and diagram Number collected matic sketch by Quinn (1963, p. 26-28, figs. 1, 2), Syngastrioceras globosutn (Easton) _______ 205 who regarded the ammonoid-bearing bed as be Bisatoceras paynei Gordon ____________ 1 longing in the Cane Hill Member. The ammonoid Hudsonoceras moorei Quinn and Saunders __ 2 fauna collected here is as follows: Reticuloceras tiro n. sp _______________ 11 Reticuloceras? wainwrighti ____________ 10 Number collected Syngastrioceras globosum (Easton) _______ 50 Branneroceras semiretia (McCaleb) _______ 29 Bisatoceras paynei Gordon _____________ 5 Cymoceras adonis n. sp ______________ 18 Hudsonoceras moorei Quinn and Saunders __ 1 Stenopronorites guinni n. sp ___________ 4 Reticuloceras tiro n. sp ______________ 7 Also, on the east slope of Sequoyah (East) Moun Reticuloceras? wainwrighti Quinn _______ 5 tain (fig. 1, loc. 5) the following were collected: Branneroceras semiretia (McCaleb) _______ 80 Number collected Cymoceras adonis n. sp ______________ 16 Syngastrioceras globosum (Easton) ______ 16 Stenopronorites quinni n. sp ___________