BRIGHAM YOUNG UNIVERSITY BRIGHAM YOUNG UNIVERSITY GEOLOGY STUDIES Volume 44,1999 CONTENTS Symmetrodonts from the Late Cretaceous of Southern Utah, and Comments on the Distribution of Archaic Mammalian Lineages Persisting into the Cretaceous of North America ................................ Richard L. Cifelli and Cynthia L. Gordon I A Large Protospongia Hicksi Hinde, 1887, from the Middle Cambrian Spence Shale of Southeastern Idaho ................................ Stephen B. Church, J. Keith Rigby, Lloyd E Gunther, and Val G. Gunther 17 Iapetonudus (N. gen.) and Iapetognathus Landing, Unusual Earliest Ordovician Multielement Conodont Taxa and Their Utility for Biostratigraphy .................................. Robert S. Nicoll, James E Miller, Godfrey S. Nowlan, John E. Repetski, and Raymond L. Ethington 27 Sponges from the Ibexian (Ordovician) McKelligon Canyon and Victorio Hills Formations in the Southern Franklin Mountains, Texas ...............J. Keith Rigby, C. Blair Linford, and David Y LeMone 103 Lower Ordovician Sponges from the Manitou Formation in Central Colorado ...................................................... J. Keith Rigby and Paul M. Myrow 135 Sponges from the Middle Permian Quinn River Formation, Bilk Creek Mountains, Humboldt County, Nevada .............................. J. Keith Rigby and Rex A. Hanger 155 A Publication of the Department of Geology Brigham Young University Provo, Utah 84602 Editor Bart J. Kowallis Brigham Young University Geology Studies is published by the Department of Geology. This publication consists of graduate student and faculty research within the department as well as papers submitted by outside contributors. Each article submitted is externally reviewed by at least two qualified persons. ISSN 0068-1016 6-99 650 29580 Sponges from the Middle Permian Quinn River Formation, Bilk Creek Mountains, Humboldt County, Nevada J. KEITH RIGBY Department of Geology, S-389 Eyring Science Center, Brigham Young University, Provo, Utah 84602-4606 REX A. HANGER Department of Geology, Room 102 Bell Hall, George Washington University, 2029 G Street, Washington D. C. 20052 ABSTRACT The rhizomorine demosponge Haplistion aeluroglossa Finks, 1960, and an unidentifiable anthaspidellid orchocladinid demosponge are reported for the first time from the Quinn River Formation (Middle Permian), Bilk Creek Mountains, northern Nevada. This is the first time that this species has been reported outside the West Texas region. The fossils have been partially silicified in a dolomitic matrix. INTRODUCTION Sponges- - in the collection consist principally of the rhi- zomorine Haplistion aeluroglossa Finks, 1960, and an un- A small fauna of demosponges was collected by Hanger identifiable anthaspidellid tetracladine sponge. All occur from the Guadalupian part of the Quinn River Formation in the more or less in-place assemblage. in the Bilk Creek Mountains in northern Nevada (Fig. 1). As with the fossils recovered from the Cache Creek The sponges occur in a massive, light-brownish grey cal- Group of British Columbia (Rigby, 1973), the sponges of careous and cherty dolomite. They have been partially re- the Quinn River Formation characterize Boreal faunas of placed by silica so that in surface exposures their detailed Arctic Canada, Spitsbergen and Russia and suggest no structure and microstructure have been largely lost. Cut slabs that show skeletal materials have also been replaced major tectonic transport, although they are distinct from in sample interiors by dark gray silica and their micro- coeval North American faunas (Rigby and Senowbari- structure largely destroyed. However, thin sections do show Daryan, 1995). some spicules are preserved in both species of sponges in The fossil locality occurs on the Mustang Spring, the fauna. Nevada, 7.5 minute quadrangle (figure 1).The UTM coor- The Quinn River Formation is well dated by radiolari- dinate is llTLS89159890. The geographic coordinates are ans, conodonts, and brachiopods (Blome and Reed, 1995) 41 "32'10N, 118"19'48"W. Figured and reference speci- and ranges from Middle Permian to the Late Triassic. The mens of the collections have been deposited in the U.S. sponges described here are from the top of a conspicuous National Museum, Washington D.C. dolomitic unit immediately above strata bearing a Middle Permian (Guadalupian-Wordian) fauna (Fig. 2). SYSTEMATIC PALEONTOLOGY Paleozoic strata of the Bilk Creek Mountains are part of Class DEMOSPONGEA Sollas, 1875 the Black Rock Terrane of northwestern Nevada (Silberling Order LITHISTIDA Schmidt, 1870 et al., 1987), one of the "McCloud Belt" of terranes in Suborder RHIZOMORINA Zittel, 1878 western North America that are grouped based upon sim- Family HAPLISTIIDAE De Laubenfels, 1955 ilar lithologic sequence and distinctive McCloud province Genus HAPLISTION Young and Young, 1877 faunas (Miller, 1987; Stevens et a]., 1990). Great controversy HAPLISTION AELUROGLOSSA Finks, 1960 exists concerning the original paleogeographic position of Figs. 3.1, 3.2, 3.4-3.8 these terranes, and faunal data to date have been equivo- cal in determining paleolongitudinal separation between Haplistion aeluroglossa Finks, 1960 p. 89-90, pl. 19, figs. terranes and the North American continent (Jones, 1990). 8-10, pl. 26, figs. 9-12, pl. 27, figs. 1, 2 156 BYU GEOLOGY STUDIES 1999, VOL. 44 MiieTriassic radiolarians and conodonts Early to Mile Tfiassic ammonite and radiobrians Primitive radiolarians Early Triassic radiolarians Figure 1. Index map to the sponge locality (arrow)frorn the Quinn Rir;er Formation, in the Bilk Creek Mountains, Hurnboldt County, northwestern Nevada. It is on the Mustang Spring, Nevada, 7.5- minute quadrangle. Nevada State Highway 140 between Denio and the Fort McDennitt Indian Reser~ation,northwest of Winne- mucca, crosses the southwest corner of the map. Wordian conodonls and radiolarians Diagnosis.-"Flattened-spherical to lobate or digitate; tract diameters in the species small for genus; a few small, circular osculae present, opening into a short radial canal; Sponges surface strongly hispid (Finks, 1960, p. 89). earb Description.-Numerous examples of this small sponge - Wordian range from irregularly massive or lobate to digitate or sub- brachiopods cylindrical. Lobate masses range to 50-60 mm across with lobes commonly 10-25 mm across, lobes locally produc- Figure 2. Genc-ralized stratigrc~phicsection of the Quinn Ri~er ing small branches or stems range 5-10 mm in diameter. Formation. Occurrence of tlze sponges is indicated by tlze clrrow Some isolated sponges appear to be juveniles and others (modified frorn Blorne clnrl Reed, 1995). An unconformity must have flared attachment bases, apparently as initial phases exist between Early Triclssic beds and Wordian beds in the lower of massive lobate development. Individual stems range to part ofthe section, hut its position is uncertain RIGBY AND HANGER: PERMIAN SPONGES 157 4045 mm long, although most are approximately half that and range to at least 0.8 mm long. Some have faint im- length; longer stems are larger and commonly 10-15 mm pressions of axial canals. in diameter. Smaller stems only 15-20 mm long, with Transverse sections of well-preserved tracts show dif- those 5-7 mm in diameter most common. The skeleton is ferences in tract diameters and numbers of spicules. Small made of spicule tracts, longitudinal ones characteristically tracts, 0.1 mm in diameter, are composed of 7-10 spicules, radiating upward and outward from the point of attach- intermediate-sized tracts, 0.25 mm in diameter, have ment, or from the center of the lobate mass. These are 15-17 spicules, and larger tracts, 0.5 mm in diameter, cross-connected by irregularly placed horizontal tracts, to have 2530 spicules. produce an irregular, sub-rectangular net. Horizontal Discussion.-Finks (1960, p. 88) subdivided the species tracts not at uniform levels, although two or three may be of Haplistion into two large groups. These were based at the same level, laterally, in the skeletal structure. Tracts upon whether mesh spaces are less than 1 mm in diame- range 0.20-0.30 mm in diameter in their narrow centers, ter, whether radial and horizontal tracts are approximately but expand at junctions to about 0.40-0.50 mm across. of equal thickness or diameter, or whether mesh spaces Tracts are spaced 0.60.7 mm apart throughout much of are 1 mm or more in diameter and horizontal tracts are about half the diameter of radial tracts. It is with the first the structure, although locally some are up to 1.1 mm group, with small mesh spaces, that the specimens here apart in the upward-divergent part of the skeleton. seem to be related. Finks also recognized three subgroups Some skeletons are locally interrupted by irregular cen- in group 1, based upon whether skeletal tracts are less tral canals that are 13mm in diameter. Such canals are than or about 0.5 mm in diameter, or whether tract diame- most commonly present in the smaller branches or stems ters are not known. Within the first group, he included that are 10 mm or less across. These central canals are Haplistion arrnstrongi Young and Young, 1877, a Missis- interconnected throughout their length by coarse canals. sippian form from the British Isles, and Haplistion aeluro- Longitudinal sections of obconical to branching struc- glossa Finks, 1960, from the Permian ofwestern Texas. tures show distinct upwardly divergent skeletal struc- Haplistion skinneri (R. H. King, 1943), also known from tures, with vertical tracts arching outward from the axis of the Permian, is a spheroidal form with regular structure in the structure, becoming subhorizontal in the outer few a skeleton lacking well-defined oscules. Haplistion skinned millimeters of the sponge. So called horizontal tracts are has both concentric and radial tracts of essentially the roughly at right angles to the upwardly divergent tracts same diameter and spacing. Finks (1960, p. 90) observed and have a distinct domal pattern, becoming almost verti- that in H. skinneri the total range of thickness of tracts is cal and tangential near the outer surface, at right angles to 0.25-0.60 mm in diameter, and that tracts are 0.5-1.2 mm the radial fibers.