Lower Tertiary Crinoids from Northwestern Oregon
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Lower Tertiary Crinoids from Northwestern Oregon GEOLOGICAL SURVEY PROFESSIONAL PAPER 233-E Lower Tertiary Crinoids from Northwestern Oregon By RAYMOND C. MOORE and HAROLD E. YOKES SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1950-1951, PAGES 113-148 GEOLOGICAL SURVEY PROFESSIONAL PAPER 233-E UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1953 UNITED STATES DEPARTMENT OF THE INTERIOR Oscar L. Chapman, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price $1.00 CONTENTS Page Page Abstract_________________________________________ 113 Description of crinoids—Continued Introduction _______________________________________ 113 Isocrinus oregonensis—Continued Discov.ery of crinoid remains in Oregon.___________ 113 Dorsal cup_---_----_--------_----_--------- 128 Occurrence of Tertiary crinoids elsewhere in the Rays, exclusive of radials. ___________________ 130 Western Hemisphere._________________________ 116 Column. ___________________________ 132 Acknowledgments__ ___________________________ 118 Discussion _________________________________ 134 The Oregon crinoid-bearing beds____________________ 118 Isocrinus nehalemensis Moore and Yokes, n. sp_____ 135 Lithologic and paleontologic characters of the Keasey formation.___________________________________ 118 Summary of description.____________________ 136 Age of the Keasey formation.____________________ 119 Description of specimens___________________ 136 Outcrops of the Keasey formation from which crinoid Holotype—.____________________ 136 remains have been collected.____________________ 120 Paratypes.____________________________ 136 Description of crinoids_____________________________- 120 Dorsal cup_______________________________ 136 Material available for study____________________ 120 Ray structure-_____-------_--_-_-___---____ 136 Suprafamilial placement of the Oregon crinoids_____ 121 Column. _ _____________________________ 138 Family Isocrinidae GislSn, 1924________________ 121 Discussion. ________________________________ 139 Genus Isocrinus von Meyer, 1837_________________ 122 Species of Isocrinus described from Tertiary rocks in other Characters of Isocrinus-. ____________________ 122 parts of the world _________________________________ 139 Comparison with related"genera______________ 123 Paleoecology of the Keasey crinoids.__________________ 140 Isocrinus oregonensis Moore and Yokes, n. sp_____ 124 General statement-_______-_-------___-______-__ 140 Summary of description____________________ 124 Physical features_______________________________ 140 Description of specimens___________________ 124 Organic evidence.______-_--__-_-___-_-_-___--__ 141 Holotype._--------_-----_------_-_--__ 124 References-________--__--_-----------_---_--------_ 142 Paratypes____________________________ 124 Index-______-______----------------_-----_-------_ 145 ILLUSTRATIONS [Plates 14-24 follow index] PLATES 14—18. Isocrinus oregonensis 19, 20. Isocrinus oregonensis and /. nehalemensis 21. Crinoid locality near Mist, Oregon, and Isocrinus nehalemensis 22. Isocrinus nehalemensis, I. oregonensis, and associated plant remains 23. Isocrinus columnals from the Keasey formation, Oregon 24. Isocrinus oregonensis Page FIGURE 27. Maps of upper Nehalem basin, northwestern Oregon, showing crinoid localities.______________________ 114 28. Columnar section of the Keasey formation________________________-______-_--------_-----_------- 115 29. Holotype of Isocrinus oregonensis.-------------------------------------------------------------- 125 30. Paratype A of Isocrinus ore<7<me«s*s_________________________________--_-----------------_------- 126 31. Ray structure of paratype A of Isocrinus oregonensis---------------------------------------------- 126 32. Paratype B of Isocrinus oregonensis and diagram of ray structure____________--__---_--------_--__-- 127 33. Ray structure of paratype L of Isocrinus oregonensis..--------------------------------------------- 129 34. Brachials and pinnules of the holotype of Isocrinus oregonensis -------------------------------------- 132 35. Paratypes of Isocrinus oregonensis in collections of the University of California Museum of Paleontology. 133 36. Isocrinus columnals___-_____________________________________________------__---------------_-- 133 37. Paratype C of Isocrinus nehalemensis------------------------------------------------------------ 136 38. Ray structure of holotype and two paratypes of Isocrinus nehalemensis------------------------------ 137 39. Radial plates and syzygial articulation of Isocrinus nehalemensis and cirrus socket of I. oregonensis-----. 138 in LOWER TERTIARY CRINOIDS FROM NORTHWESTERN OREGON By RAYMOND C. MOORE AND HAROLD E. VOKES ABSTRACT was collected in 1944 by Walter C. Warren and Eex M. The occurrence of numerous remains of crinoids, including Grivetti, at that time members of a field party of the nearly complete crowns, in the middle member of the Keasey United States Geological Survey engaged in prepara formation, early Tertiary, of northwestern Oregon is of more tion of a reconnaissance geologic map of northwestern than ordinary paleontological interest. Most of the marine Tertiary formations of North America are notably lacking in Oregon (Warren, Grivetti, and Norbisrath, 1945), crinoids, although in a few places abundant fragmentary re The specimen was found in a stratum of the Keasey mains of free-swimming crinoids (comatulids) have been re formation (figs. 27, 28) exposed a short distance above ported. Only five species have been described from North the level of the Nehalem Eiver in a prominent bluff America, exclusive of the West Indies. Five more species, dis located on the west side of that river approximately tinguished on the basis of stem fragments, are reported from Eocene rocks of Trinidad and Miocene deposits of Haiti and 3,500 feet south of the junction of Oregon State high Cuba. ways 47 and 202 at Mist, Columbia County, Oreg. The Oregon crinoids here described are stem-bearing forms, (U. S. Geol. Survey locality 15318). This site has long assigned to the genus Isocrinus. They constitute the first- been known as a fossil locality, first described by Diller reported occurrence of this type of crinoid in the Tertiary of in 1896 (pp. 469-470). Schenck (1936, p. 58) recog the continent. It is especially interesting to find nearly com plete crowns that rival some of the well-known pentacrinid nized it as being probably the type locality of Acila crowns from Jurassic localities in Europe. However, the Ore (Truncacila) nehalemensis G. D. Hanna, one of the gon fossils generally have the hard parts poorly preserved, and principal guide fossils of the Keasey formation. some of the best preparations for study of their structure con Crinoid material is not uncommon in a thin zone at sist of external molds. A few of the molds were formed by this outcrop, and crinoid specimens are known to be in natural weathering, but most have been prepared by etching the partly decomposed calcite with acid. the hands of amateur collectors from the Portland area. On the basis of more than a dozen crowns, some fairly com A few fragmentary specimens are in the collections at plete, and innumerable fragments of stems, arms, and pinnules, Oregon State College, Corvallis, Oreg. two species are recognized. They are named Isocrinus ore- In view of the absence of known stem-bearing crinoids gonensis and /. nehalemensis. Some fossils, preserved as cal cite, are assigned to each species, but most of the specimens in Tertiary deposits of North America outside of Ore are molds. gon, and of the fact that the occurrence of crinoids at The Keasey formation includes deposits belonging to the up the Columbia County locality was fairly well known permost Eocene and lower Oligocene. Analysis of the molluscan locally some time before collection of specimens by the fauna, which is associated with the crinoids in the middle mem U. S. Geological Survey party, it is rather surprising ber of the Keasey formation, indicates that the crinoid-bearing beds are probably of early Oligocene age. that these fossils have not been reported earlier. If The matrix in which the fossils are embedded is a highly west coast paleontologists knew of the Keasey crinoids tuffaceous, mostly fine-grained, hard, massive siltstone. Lo they must not have apprehended the extreme rareness cally, it contains scattered ash "pebbles" % in. or more in and fragmentary condition of described stem-bearing diameter. The articulated condition of most of the crinoid crinoids elsewhere in Tertiary deposits of the world. material indicates very quiet water sedimentation, which cer tainly does not belong in a wave-agitated, near-shore zone. The fossils are important because of the very meager That land was not far away from the sites where crinoids were record of stem-bearing crinoids in North America be buried during Keasey sedimentation, however, is indicated by tween Late Cretaceous and the present time. the ash "pebbles" and especially by occurrence of well-preserved In addition to the relatively complete crowns de land plants, which are mingled with the mollusks and crinoids. The environment of deposition, accordingly, is interpreted to scribed from the locality near Mist, crinoid stem seg denote moderately deep water- adjacent to a land on which ments occur at four other localities in the Keasey forma explosive-type volcanic activity existed during at least middle tion. The material