Occurrence, Stratigraphic Distribution, and Abundance of Chitinozoa from the Middle Devonian Columbus Limestone of Ohio1

OCCURRENCE, STRATIGRAPHIC DISTRIBUTION, AND ABUNDANCE OF CHITINOZOA FROM THE MIDDLE DEVONIAN COLUMBUS LIMESTONE OF OHIO1

ROBERT P. WRIGHT, The Department of Geology and Mineralogy, The Ohio State University, Marion, Ohio

Abstract. Chitinozoa from the Middle Devonian Columbus Limestone of central Ohio belong to eight species of the genera Alpenachitina, Ancyrochitina, Angochitina, Conochitina, Desmochitina, and Eisenackitina. Two new species, Ancyrochitina frankeli and Eisenackitina robusta, are described. The Chitinozoa occur in carbonate rocks such as mudstone, grainstone and packstone that represent well circulated open marine conditions. They are absent from dolomite which represents sediment deposited at a shallow water depositional site characterized by restricted water circulation. Comparison of the Columbus Limestone Chitinozoa with faunas from similar Middle Devonian strata in Iowa, Illinois, and Missouri indicates that the Middle Devonian Wabash Platform, located in Indiana, effectively restricted the distribution of chitinozoans in the Illinois and Appalachian Basins.

OHIO J. SCI. 76(5): 214, 1976

Chitinozoa were first described in the America. Second, Chitinozoa appear to 193()'s by the German scientist A. be useful bathymetric indicators (Wil- Eisenack (1930, 1931) from Silurian gla- liams and Sarjeant, 1967; Gray et al, cial erratics in the Baltic region of 1974). Laufeld (1975) has noted, in the Europe. Since that time interest in this Silurian of Gotland, Chitinozoa diversity group of extinct organic-walled micro- and abundance increase away from organisms has grown in Europe and the reefoid detrital limestones in the direction Americas as exemplified by the recent of deeper water. monographic treatment of the group The dominant feature of the Middle (Combaz et al, 1967; Taugourdeau et al, Devonian paleogeography of Indiana, 1967). The interest of North American Illinois, and Ohio is now recognized as paleontologists in this group of fossils consisting of a broad shallow water car- has grown steadily since the 1950's. bonate shelf (Droste et al, 1975). That The importance of Chitinozoa is two- shelf, called the Wabash Platform, con- fold. They are abundant and easily ex- trolled the sedimentology of adjacent ba- tracted from strata of Ordovician through sins in Missouri, Iowa, Illinois, Michigan, Devonian age and, as some of the forms and Ohio. It must have influenced the may have been members of the lower spatial and temporal distribution of the Paleozoic zooplankton (Chaiffetz, 1972), marine plankton and members of the their biostratigraphic value is obvious. benthic fauna. In this regard, the de- The presence of Chitinozoa in the Co- scription of the Columbus Limestone lumbus Limestone as well as faunas from Chitinozoa is the necessary first step in strata of similar age elsewhere in the establishing the degree of Chitinozoa Midwest (Urban, 1972; Urban and New- faunal interchange in the Illinois, Michi- port, 1973; Legault, 1973; Wood, 1974) gan, and Appalachian Basins. The pur- suggest their potential importance for the pose of this paper is to describe the oc- refinement of the biostratigraphy of Mid- currence, stratigraphic distribution, and dle and Upper Devonian strata in North abundance of Chitinozoa in the Middle xManuscript received January 28, 1976 and in Devonian Columbus Limestone in north- revised form May 18, 1976 (#76-11). central Ohio. 214 No. 5 COLUMBUS LIMESTONE CHITINOZOA 215

METHODS AND MATERIALS environments represented by the various car- Collections for this study were obtained from bonate lithofacies and to attempt to identify the Hamilton Brothers Quarry near Marion, the environmental occurrence of the Chitinozoa. Ohio. The Columbus Limestone is well ex- Fresh samples were taken systematically at posed and stratigraphically complete at this two-foot vertical intervals or at every change locality (tig. 1). The strata were examined in in lithology. In all, 41 samples were treated detail in order to determine the depositional using the following techniques. Fifty grams

Abundance of chitinozoans in 50 grams of rock Legend

Bivalves £>J Grainstone ^J Ripple marks

Bone bed |^| Horn corals |@| Sample number

Brachiopods 1 Mudstone J Shale

Bryozoans [—H Oil stain |^| Stromatoporoids

Chert \Mi Packstone \~~[ Stylolites

Dolomite |^| Pelmatozoans [

[^1 Calcite-filled vugs

FIGURE 1. Stratigraphic section of the Columbus Limestone exposed in the Hamilton Brothers Quarry. The section shows the vertical destribution of carbonate lithofacies and Chitinozoa. 216 ROBERT P. WRIGHT Vol. 76 from each sample were placed in beakers and water circulation. At the Hamilton covered with concentrated HC1. After the re- action ceased, the acid was diluted and sedi- Quarry, the so-called "coral-stromato- ment washed by filling the beaker with tap poroid zone" is well developed, and water and sieved according to a procedure de- marks the beginning of open marine con- scribed by Laufeld (1974). The sieving cloth ditions. The association of stromatopor- had a mesh distance of 45 microns. After sieving and washing, the residue was oid sponges, tabulate and rugose corals poured into a beaker and treated with concen- that characterizes this unit represents trated HF, and allowed to stand for 24 hours stabilization of the mud substrate by until the silica was digested. The acid was bottom dwelling "carpeting" organisms. then diluted with water and the residue sieved, washed, and stored in small vials filled with The skeletal-poor mudstone above the distilled water. Identification and counts of biostrome is a low energy, below wave- each taxon were made and recorded. The best base deposit (Chapel, 1975). The oc- specimens were removed from the beakers with currence of the mudstone above the bio- a finely drawn glass pipette and prepared for scanning electron microscopy. Four to six strome indicates deepening of the water specimens were mounted on a glass coverslip over the coral-stromatoporoid studded using a graphite adhesive. The specimens were shallow platform. coated with gold in a vacuum apparatus and studied using a Cambridge S4 Stereoscan The fossiliferous packstone midway (SEM). through the section records regression or All specimens were deposited in the Orton shallowing of the water. The abundance Museum at The Ohio State University in of specimens of Brevispirifer gregarious as Columbus, Ohio and designated with OSU num- well as the appearance of other species of bers. SEM stubs containing the specimens are coded thusly: In 1-29, 1 = stub number, 29= field brachiopods, corals, molluscs, bryozoans, number. and pelmatozoans indicate that circulation kept the bottom relatively free of GENERAL STRATIGRAPHY AND large amounts of carbonate mud that DEPOSITIONAL FRAMEWORK would have smothered many of the filter Columbus Limestone crops out in a and suspension feeders. narrow belt from the Columbus area The cherty mudstones near the top of north to Kelly's Island in Lake Erie. the stratigraphic section do not contain In central Ohio the formation consists of large quantities of skeletal material, ex- a lower dolomite unit and an upper lime- cept Chitinozoa. The mudstones repre- stone unit. At the Hamilton Quarry the sent a semi-restricted above wave-base dolomite is less than 25 feet thick, rela- deposit, perhaps deposited in an environ- tively unfossiliferous and banded with ment that was somewhat lagoonal. The hydrocarbons (fig. 1). The dolomite was peaks in abundance of the Chitinozoa in deposited in shallow water with restricted the cherty mudstone indicate that the circulation when submergence of the low- rate of sedimentation at this time was lying weathered craton took place during less than when the packstones and grain- Early and Middle Devonian. The over- stones were deposited. lying fossiliferous limestone was deposited The grainstone in the uppermost por- in an open marine environment with good tion of the Columbus Limestone, with its

EXPLANATION OF FIGURE 2 No. 1-6. Scanning electron micrographs of Ancyrochitina frankeli Wright, n. sp. 1. Paratypc, OSU 32159, X600, 4-32. 2. Paratype, OSU 32158, X900, 4-32, high magnification showing the oral end of the specimen. 3. Paratype, OSU 32157, X450, 4-32. 4. Paratype, OSU 32156, X525, 3-31, note the clavate basal spine. 5. Holotype, OSU 32155, X525, 3-31, specimen shows the long neck in proportion to the body chamber and the bifurcating neck and basal spines. 6. Paratype, OSU 32154, X525, 3-31, note absence of neck spines. No. 7-9. Scanning electron micrographs of Alpenachitina eisenacki Dunn and Miller, 1964. 7. Note the small spines at the base, OSU 32153, X575, 2-35. 8. Specimen showing the delicate branching of the vesicle spines, OSU 32152, X575, 2-40. 9. Note the length of the neck in comparison to the body chamber, OSU 32151, X575, 1-29. No. 5 COLUMBUS LIMESTONE CHITINOZOA 217

FIGURE 2 218 ROBERT P. WRIGHT Vol. 76

crinoidal debris, abraded ripples (Bates, to the relative abundance of the other 1971), and bone beds representing lag species throughout the rest of the section. concentrations, abruptly changing to Cramer (1970) has suggested that an mudstone in the overlying Delaware enormous increase in the abundance of Limestone indicates transgression and Chitinozoa within just a few inches of submergence. rock may represent a planktic bloom similar to blooms in modern coastal CHITINOZOA waters. An alternative, and probably Representatives of six genera and eight correct, explanation is that the increase species of Chitinozoa were collected from in numbers of specimens is a conse- the Columbus Limestone. Their distri- quence of the relatively slower sedimen- bution is not random through the section tation rate of the mudstone in compari- as they are more abundant in the mud- son to the coarser-grained carbonates. stones than in the grainstones and pack- The Columbus Limestone, by being de- stones. Their small numbers in the posited in very shallow water, precludes coarse-grained sediments do not appear planktic blooms from being recorded. to be a function of selective preservation, The regional distribution pattern of as well preserved specimens of forms with Chitinozoa suggests that the Wabash delicate spines (e.g., Alpenachitina eisen- Platform influenced their geographic dis- acki) are common in these deposits. tribution. Ancyrochitina frankeli, Cono- It is apparent that Chitinozoa are ab- chitina inflata, and Eisenackitina robusta sent in the dolomite below the coral- appear to be unique to Middle Devonian stromatoporoid layer. Their absence was strata in Ohio and Ontario in so far as not caused by vescile destruction during these species are not part of the chiti- dolomitization because the Chitinozoa are nozoan faunas of the Cedar Valley For- present and well preserved in the dolo- mation and Wapsipinicon Formation of mitized mudstone immediately above the Iowa and northwestern Illinois or the coral-stromatoporoid interval. The ab- Cedar City Formation in Missouri. sence of Chitinozoa in the dolomite and Ancyrochitina frankeli and Conochitina first occurrence above the coral-stroma- inflata are known from the Silica Forma- toporoid interval is interpreted as a tion (Wood, 1974) in northeastern Ohio, transition from a nearshore restricted the Dundee Limestone (Hill, 1975) near shallow water environment to an off- St. Mary's, Ontario and the Columbus shore, deeper water area with well circu- Limestone as reported here. Specimens lated water. referred to as Eisenackitina robusta have Ancyrochitina frankeli (fig. 2) domi- not been reported from Middle Devonian nates the chitinozoan fauna in the cherty sediments, other than the Columbus mudstone. The great abundance of A. Limestone. frankeli, well over 1,000 specimens per 50 In spite of the apparent effectiveness of grams of rock, stands out in comparison the broad shallow platform in acting as a

EXPLANATION OF FIGURE 3 No. 1-5. Scanning electron micrographs of Desmochitina arunea Urban, 1972. 1. Specimen shows the slight bulge at the base of the chamber, OSU 32168, X500, 10-41. 2. Note the ornamentation of short verrucae that is characteristic of this species when the periderre is preserved, OSU 32167, X575, 9-41. 3. Note the prominent membranous collar that is devoid of ornamentation, OSU 32166, X575, 9-41. 4. Shows the cylindro-oval shape which is typical for the species, OSU 32165, X575, 8-41. 5. Specimen shows the basal callus, OSU 32164, X575, 7-41. No. 6. Scanning electron micrograph of Ancyrochitina sp. 6. Note the abnormally directed basal spines, OSU 32163, X500, 6-35. No. 7-9. Scanning electron micrograph of Ancyrochitina cf. A . langei Sommer and van Boekel, 1964. 7. An 4. langei type, OSU 32162, X525, 3-31. 8. Specimen shows how the spines are unbranched and curl in an oral direction, OSU 32161, X550, 4-29. 9. Note the appendices are attached without any connection to the vesicle interior, OSU 32160, X500, 5-29. No. 5 COLUMBUS LIMESTONE CHITINOZOA 219

FIGURE 3 220 ROBERT P. WRIGHT Vol. 76

faunal barrier to some species in the Mid- Alpenachitina eisenacki Dunn and west, geographic isolation between the Miller, 1964 eastern (Ohio, Ontario, Michigan) and Fig. 2 (7-9) western (Iowa, Illinois, Missouri) portions of that platform was not complete. Genus Ancyrochitina Eisenack, 1955 Desmochitina aranea, Alpenachitina eisen- Type species: acki, and Angochitina devonica are com- Conochitina ancyrea Eisenack, 1931 mon to Middle Devonian sediments de- Ancyrochitina frankeli n. sp. posited along both sides of the Wabash Fig. 2 (1-6) Platform. Mapping the distribution of chitinozoans from Middle Devonian Ancyrochitina cf. A. ancyrea (Eisenack) strata in Indiana and in Illinois will help (Wood, G., 1974, p. 135, pi. 7, figs. 1, 2). determine the degree of faunal interchange between the areas east and west of the platform and permit comparison with Chitinozoa faunas from Middle De- vonian strata in Iowa, Missouri and Ontario. Most of the species of Chitinozoa in the Columbus Limestone, except Eisen- ackitina robusta, occur in the Middle Dev- onian strata elsewhere in the Midwest. With my findings of Alpenachitina eisenacki and Desmochitina aranea in the Co- lumbus Limestone, the stratigraphic range of these species is now extended to include the entire Middle Devonian. Conochi- tina inflata and Ancyrochitina frankeli are now known to occur in the Columbus Limestone, Dundee Limestone, and Silica Formation, representing Eifelian and early Givetian strata of the Middle Devonian in North America. SYSTEMATIC PALEONTOLOGY CHITINOZOA, Eisenack, 1931 Genus Alpenachitina Dunn and Miller, 1964 FIGURE 4. Drawing of Angochilina devonica Type species: showing the specimens profile and nearly circular, elevated spine at- Alpenachitina eisenacki Dunn and tachment scars distributed ran- Miller, 1964 domly on the vesicle.

EXPLANATION GF FIGURE 5 No. 1-2. Scanning electron micrographs of Conochitina inflata Wood, 1974. 1. Note the swollen shoulder, characteristic of the species, OSU 32177, X500, 6-17. 2. Specimen shows the swollen base of the cylindrical vesicle, OSU 32176, X500, 12-17. No. 3-9. Scanning electron micrograph of Eisenackitina robusta Wright, n. sp. 3. Paratype, OSU 32175, X500, 12-17, heavily ornamented aboral portion of the vesicle wall and the well defined collar. 4. Paratype, OSU 32174, X600, 11-13, the surface of this specimen is relatively smooth due to degradation of the ornamentation. 5. Paratype, OSU 32173, X500, 10-13, note how the ornamentation is greatest on the aborally inflated portion of the vesicle. 6. Holotype, OSU 32172, X500, 10-13, note the expanded aboral portion of the chamber and the coarsely verrucate ornamentation which characterizes this species. 7. Paratype, OSU 32171, X575, 13-16. 8. Paratype, OSU 32170, X575, 6-16, specimen shows the prominent basal callus. 9. Paratype, OSU 32169, X450, 11-16, note the ornamentation. No. 5 COLUMBUS LIMESTONE CHITINOZOA 221

FIGURE 5 222 ROBERT P. WRIGHT Vol. 76 Derivation of name: In honor of Dr. reported by Taugourdeau (1965) from Larry Frankel, paleontologist at the Uni- France possess sharply conical body versity of Connecticut. chambers with a shorter neck than the Description: The vesicle is cylindro- Silurian forms from Gotland. Repre- conical to pyriform with a flat or slightly sentatives of A. frankeli from the Eifelian convex base. Vesicle collapse results in and Givetian of North America exhibit a a convex base and a compressed neck and different silhouette than do the specimens body chamber. Ornamentation consists illustrated by Pichler and Taugourdeau of basal and neck spines, both of which in that the body chamber is not as sharply vary in number, size, and shape. Basal conical and the neck much longer in pro- spines are in most cases 4 to 6 in number, portion to the body chamber. In addi- but may be up to 8, are hollow, long, and tion, the basal spines of A. frankeli commonly delicately bifurcated at their typically bifrucate at their distal ends, tips. Several specimens possess clavate whereas those of Pichler's specimens are spines. Spines may be thick or thin and multibranched. Individuals of A. frankeli both types may occur on the same speci- have broadly based and often clavate men. The spines on the neck vary in basal spines and, when present, long shape from short, thick spikes to long delicate neck spines which distinguish delicate simple or bifurcating ones. A them from the Gotland specimens (Lau- collar is often distinguishable. The sur- feld, 1974). A. frankeli, therefore, is a face of the vesicle is usually smooth, distinct species characteristic of the Mid- however some specimens have a finely dle Devonian. The form has not been verrucate ornamentation. reported from any other North American Dimensions: Population from the type localities outside Ontario (Hill, 1975) and stratum in microns: length (excel.) 120- northern Ohio (Wood, 1974). 195 (holotype 140), width (exl.) 60-100 (holotype 66), maximum length of basal Ancyrochitina cf. spines 30 (holotype 30). A. langei Sommer and van Boekel, 1964 Types: Holotype OSU 32155, Para- Fig. 3 (7-9) types OSU 32154, 32156, 32157, 32158, 32159. Ancyrochitina sp. Type stratum and locality: Cherty lime- Fig. 3 (6) stone (sample 31), forty feet above the Genus Angochitina Eisenack, 1931 "coral-stromatoporoid zone," the Co- Type species: lumbus Limestone, Hamilton Brothers Angochitina echinata Eisenack, 1931 Lime and Stone Quarry, Marion, Ohio. Angochitina devonica Eisenack, 1955 Discussion: Ancyrochitina frankeli is Fig. 4 the most abundant chitinozoan species in The Columbus Limestone. More than Genus Conochitina Eisenack, 1931 3,000 specimens were examined. Al- Type species: though the vesicle morphology is some- Conochitina claviformis Eisenack, 1931 what variable, the species is distinct in Conochitina inflata Wood, 1974 its pyriform to cylindro-conical shape Fig. 5 (1-2) which resembles that of Ancyrochitina ancyrea. A. ancyrea is reported to have Genus Desmochitina Eisenack, 1931 a long stratigraphic range (Ordovician Type species: through Devonian) and to be a cosmo- Desmochitina nodosa Eisenack, 1931 politan form. Laufeld (1974) has re- Desmochitina aranea Urban, 1972 stricted the scope of the species and re- Fig. 3 (1-5) ports it as characteristic of the Silurian. Specimens of A. ancyrea reported from Genus Eisenackitina Jansonius, 1964 the Devonian may not be conspecific Type species: with the A. ancyrea of the Silurian. Eisenackitina castor Jansonius, 1964 Pichler's (1971) figured specimens of A. Eisenackitina robusta n. sp. ancyrea from the Devonian of the Eifel Fig. 5 (3-9) Synclinorium, West Germany, and those Derivation of name: Latin robusta, No. 5 COLUMBUS LIMESTONE CHITINOZOA 223 physically strong and powerful referring LITERATURE CITED to the general appearance of the vesicle. Bates, R. L. 1971. Abraded ripple-marked surfaces in Columbus Limestone, Central Description: Vesicle is subconical to Ohio. Ohio J. Sci. 71: 233-240. subcylindrical with sides that vary from Chaiffetz, M. S". 1972. Functional interpreta- slightly to strongly convex. The shoulder tion of the sacs of Ancyrochitina fragilis Eisenack and the paleobiology of the ancyro- is distinct; the neck is reduced to a narrow chitinids. J. Paleontol. 46: 499-502. collar that flares in oral direction. The Chapel, J. 1975. Petrology and depositional aboral portion of the chamber expands history of Devonian carbonates in Ohio. prominently at the basal edge; the base Unpub. Ph.D. Thesis, The Ohio State University. is convex and possesses a prominent basal Combaz, A., F. Calandra, J. Jansonius, P. callus. The surface of the vesicle has a Millepied, C. Poumot and F. H. Van Oyen. verrucate ornamentation and in some 1967. Microfossiles organiqucs du Paleo- specimens the swollen basal edge is more zoique 2, Les Chitinozoaires, Morphographie. heavily verrucate than the remaining Ed. Centre. Nat. Rech. Scient. (Paris): 1-47. Cramer, F. H. 1970. Angochitina sinica, a new chamber wall. The fine verrucae on a Siluro-Devonian Chitinozoan from Yumman very few specimens may be a result of Province, China. J. Paleontol. 44: 1122- degradation of the vesicle surface from 1124. a more verrucate condition. Droste, J. B., R. H. Shaver and J. D. Lazor. 1975. Middle Devonian paleogeography of Dimensions: Population from the type the Wabash platform, Indiana, Illinois, and strata in microns: length (excl.) 160-170 Ohio. Geology 3: 269-272. Dunn, D. L. and T. H. Miller. 1964. A dis- (holotype 166), width (excl.) 110-132 tinctive Chitinozoa from the Alpena Lime- (holotype 110). stone (Middle Devonian) of Michigan. I. Types: Holotype OSU 32172, Para- Paleontol. 38: 725-728. Eisenack, A. 1930. Neue Mikrofossilien des types OSU 32169, 32170, 32171, 32173, bohemischen Silurs. Die Naturwissenschaf- 32174, 32175. ten, 18. Type stratum and locality: Dolomitized 1931. Neue Mikrofossilien des baltis- chen Silurs. I. Paleontol. Zeitschr. 13: 74- mudstone (Sample 13), five feet above 118. the "coral-stromatoporoid zone," the 1955. Chitinozoen, Hystrichospharen Columbus Limestone, Hamilton Brothers und andere Mikrofossilien aus dem Beyrichia- Lime and Stone Quarry, Marion, Ohio. Kalk. Senck. Leth. 36: 157-188. Gray, J., S. Laufeld and A. Boucot. 1974. Discussion: This species is tentatively Silurian trilete spores and spore tetrads from assigned to the genus Eisenackitina. The Gotland: their implication for land plant evolution. Science 185: 260-263. elongate shape of the vesicle is typical of Hill, J. 1975. Some Chitinozoa of the Dun- Eisenackitina and the distinct collar is dee Limestone, St. Mary's, Ontario. Unpub. similar to that found in specimens of E. B.S. Thesis, Univ. Western Ontario. canadensis (Legault, 1973) and E. syl- Jansonius, J. 1964. Morphology and classifi- cation of some Chitinozoa. Canad. Petrol. vaniensis (Wood, 1974). Legault (1973, Geol. Bull. 12: 901-918. p. 91, pi. 8, figs. 3, 9) has noted bulging Laufeld, S. 1974. Silurian Chitinozoa from at the basal edge in specimens which she Gotland. Fossils and Strata 5: 1-130. has referred to as Eisenackitina. The 1975. Paleoecology of Silurian poly- chaetes and chitinozoans in a reef controlled number of characteristics of E. robusta sedimentary regime. Geol. Soc. Amer., that do fit well with the description of Abstr. with Programs, 7: 804-805 the genus justify the reference of this Legault, J. A. 1973. Chitinozoa and Acri- species, at least tentatively, to Eisen- tarcha of the Hamilton Formation (Middle Devonian), southwestern Ontario. Geol. ackitina. Surv. Canada, Bull. 221: 1-101. Acknowledgments. I wish to express my Pichler, R. 1971. Mikrofossilien aus dem gratitude to James M. Schopf, who brought to Devon der sudlichen Eifeler Kalkmulden. my attention and encouraged the investigation Senck. Lethaea. 52: 315-357. of Middle Devonian Chitinozoa. I am in- Sommer, F. W. and N. M. van Boekel. 1964. debted to Stig M. Bergstrom, James Chapel, Quitinozoarios do Devoniano de Goias. Sven Laufeld, and James Urban for reading the Acad. Brasiliero Ciencias Anais. 36: 423-431. manuscript and offering advice. Thanks are Taugourdeau, P. 1965. Trois petites associa- also due to Robert Markley who operated the tions de chitinozoaires du Frasnian du SEM, to Karen Tyler and Theodore Myers for Boulonnais. Rev. Micropaleontol. 8. preparing the illustrations, and to Pat Kocsov- , P. Bouche, A. Combaz, L. Magloire and sky for typing several versions of this paper. P. Millepied. 1967. Microfossiles organi- 224 ROBERT P. WRIGHT Vol. 76

ques du Paleozoique. 1, Les Chitinqzoaires, Williams, D. B. and W. A. S. Sarjeant. 1967. Analyse bibliographique illustree. Ed. Cen- Organic-walled microfossils as depth and tre. Nat. Rech. Scient. (Paris), 1-97. shoreline indicators. Marine Geol. 5: 389- Urban, J. B. 1972. A reexamination of Chi- 412. tinozoa from the Cedar Valley Formation of Iowa with observation on their morphology Wood, G. D. 1974. Chitinozoa of the Silica and distribution. Bull. Amer. Paleontol. 63. Formation (Middle Devonian, Ohio): vesicle and R. L. Newport. 1973. Chitinozoa ornamentation and paleoecology. Mich. State of the Wapsipinicon Formation (Middle De- Univ. Paleontol. Museum Publ. Ser. 1: 127- vonian) of Iowa: Micropaleontology. 19: 162. 239-246.