ILLINOIS STATE GEOLOGICAL SURVEY 3 3051 00000 2067 $•' Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/pennsylvanianflo52noac STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION A. M. SHELTON. Director DIVISION OF THE STATE GEOLOGICAL SURVEY M. M. LEIGHTON. Chief BULLETIN No. 52 PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS BY A. C. NOE PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS 1925 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION A. M.SH ELTON, Director DIVISION OF THE STATE GEOLOGICAL SURVEY M. M. LEIGHTON, Chief BULLETIN No. 52 PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS BY A. C. NOE PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS 1925 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION A. M. SH ELTON, Director DIVISION OF THE STATE GEOLOGICAL SURVEY M. M. LEIGHTON, Chief Committee of the Board of Natural Resources and Conservation A. M. Shelton, Chairman Director of Registration and Education Kendric C. Babcock Representing the President of the University of Illinois Edson S. Bastin Geologist PREFACE During parts of the field seasons of 1905, 1906, and 1907, the Illinois Geological Survey had the valued services of America's dean of Carbonifer- ous paleobotany, Dr. David White, in a general reconnaissance of the Upper Coal Measures, now precisely referred to as the Pennsylvania!! system. Previous to that time but little work had been done, chiefly by Leo Lesquereux from collections by A. H. Worthen and associates. White's work led to a general correlation of the strata of the Illinois coal field with the eastern field, and to a division of the Pennsylvanian system into three series: the Pottsville (lowest), the Carbondale, and the McLeansboro. In 1921, in connection with an intensive study of the coal resources of Illinois, the State Geological Survey undertook a program of a more detailed study of the plant forms found in strata associated with the coal beds, fully realizing that the facts to be uncovered by such an investiga- tion w r ould likely be of inestimable value to a proper correlation of the coal beds in different parts of our State and to our knowledge of their extent and relationships. The work is being conducted by Dr. A. C. Noe, Asso- ciate Professor of Paleobotany of the University of Chicago, and has already reached an advanced stage. The study is far-reaching in its relations to the functions of the Geolog- ical Survey, to the proper identification of coal beds which the Survey uses in determining the existence of favorable structures for the com- mercial occurrence of oil and gas, to the estimates made of the State's coal resources, to the scientific contributions which the Survey is in posi- tion to make on both the character of the vegetation, climatic environ- ment, and physiographic conditions of the Pennsylvanian period, and on the life history of the plant kingdom, and finally, with unneglected atten- tion, to providing secondary schools and colleges of the State with desir- able educational material. It is designed eventually to publish a comprehensive monograph on the flora of the Pennsylvanian system of Illinois, properly illustrated and containing descriptions of both old and new species, and the conclusions to be drawn regarding coal correlations. The field, however, is very exten- sive, and, in order that advantage may be taken of data obtained in the course of the study, short bulletins covering sub-units of the State will be issued. The present bulletin is an account of the Pennsylvanian flora of northern Illinois, marking the completion of the work of one of the sub- units. Its treatment is feasibly popular, and such technical descriptions as new and old species may require are left for the monograph. M. M. Leighton, Chief, State Geological Survey. PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS By A. C. Nee OUTLINE Part I PAGE Introduction 9 General statement 9 Location and brief description of localities 9 Collections 10 Historical review 10 Method of determination 11 Organization of the material 1 1 Acknowledgments 12 Identification of fossil plants 12 Definition of a fossil plant species 12 List of figured species 13 Discussion of figured orders and genera 15 Equisetales 15 Sphenophyllales 16 Lycopodiales 16 Filicales 16 Cycadofilicales 18 Cordaitales 18 Part II Explanation of Plates I-XLV 19 ILLUSTRATIONS PLATE PAGE I Reconstruction of swamp forest in Pennsylvanian time. After H. Potonie. 20 II Equisetales from La Salle and Braidwood regions 22 III Equisetales from Mazon Creek and Braidwood regions 24 IV 7 Equisetales from Morris and Mazon Creek regions 26 V Equisetales from Mazon Creek and Braidwood regions 28 VI Sphenophyllales from Mazon Creek and Braidwood regions 30 VII Lycopodiales from Mazon Creek region 32 VIII Lycopodiales from Braidwood and Mazon Creek regions 34 IX Lycopodiales from Mazon Creek region 36 X Lycopodiales from Mazon Creek region 38 XI Lycopodiales from Braidwood region 40 XII Lycopodiales from Braidwood 42 XIII Filicales: Sphenopteridae from Braidwood and Mazon Creek regions. ... 44 XIV Filicales: Sphenopteridae from Mazon Creek region 46 XV Filicales: Megalopteridae from Port Byron 48 XVI Filicales: Mariopteridae from Mazon Creek and Braidwood regions 50 XVII Filicales: Neuropteridae from Spring Valley and Mazon Creek regions. . 52 XVIII Filicales: Neuropteridae from Mazon Creek and Braidwood regions 54 XIX Filicales: Neuropteridae from Braidwood region 56 XX Filicales: Neuropteridae from Mazon Creek region 58 XXI Filicales: Neuropteridae from Mazon Creek region 60 XXII Filicales: Neuropteridae from Mazon Creek region 62 XXIII Filicales: Neuropteridae from Mazon Creek 64 XXIV Filicales: Neuropteridae from Mazon Creek and Braidwood regions 66 XXV Filicales: Neuropteridae from Braidwood and Mazon Creek regions .... 68 XXVI Filicales: Neuropteridae from Mazon Creek region 70 XXVII Filicales: Neuropteridae from Mazon Creek and Braidwood regions 72 XXVIII Filicales: Various fern leaf types from Mazon Creek region 74 XXIX Filicales: Pecopteridae from Mazon Creek region 76 XXX Filicales: Pecopteridae from Mazon Creek region 78 XXXI Filicales: Pecopteridae from Mazon Creek region 80 XXXII Filicales: Pecopteridae from Braidwood region 82 XXXIII Filicales: Pecopteridae from Morris region 84 XXXIV Filicales: Pecopteridae from Mazon Creek region 86 XXXV Filicales: Pecopteridae from Mazon Creek region 88 XXXVI Filicales: Pecopteridae from Mazon Creek region 90 XXXVII Filicales: Odontopteridae from Mazon Creek region 92 XXXVIII Filicales: Alethopteridae from Mazon Creek and Braidwood regions 94 XXXIX Filicales: Alethopteridae from Mazon Creek region 96 XL Filicales: Alethopteridae from Mazon Creek region 98 XLI Filicales: Callipteridae from Mazon Creek region 100 XLII Cycadofilicales: Reproductive organs. From Mazon Creek region 102 XLIII Cycadofilicales: Reproductive organs. From Mazon Creek and Braid- wood regions 104 XLIV Cycadofilicales and Cordaitales: Reproductive organs. From Braidwood and Mazon Creek regions 106 XLV Cycadofilicales, Cordaitales, and fern stems from Mazon Creek, Braid- wood and Coal City 108 PART I. TEXT INTRODUCTION General Statemkn i The Coal Measures, or the Pennsylvanian system, of Illinois lie in the heart of the Eastern Interior Coal Field which extends from southeastern Iowa on the northwest to western Indiana on the east, and from upper Illinois River on the north, to western Kentucky on the south. By far the greater part of this great coal field is in Illinois. The strata reach a maximum thickness of about 2,000 feet in southern Illinois, and contain at least five distinct commercial "veins" or beds of coal of varying extent, besides a number of local beds. As these are largely covered by later Coal Measures strata and glacial drift, the number of exposures are relatively small. Consequently, the question of the areal extent and relationships of these beds rests upon the identification of the beds by certain characteris- tics, one of which, and a very important one, is the different species and genera of fossil plants associated with each coal bed. Location and Brief Description of Localities The fossil flora herein set forth was collected from the so-called No. 2 coal bed of District 1 in northern Illinois. One of the main localities where such plants have been collected are the mine dumps northeast of Braidwood in Will County. The majority of plants from concretions and all the Braid- wood plants from shale were collected at the Skinner No. 2 mine two miles northeast of the Chicago and Alton Railroad station at Braidwood in the NW. \i of Sec. 4, T. 32 N., R. 9 E. in Will County. Two other localities where only concretions are found at present are at the so-called Ox Bow of the Mazon River, seven and ten miles southeast of Morris, located in the NW. % of Sec. 30 and the NE. M of Sec. 24, T. 33 N., R. 7 E. of Grundy County. Formerly considerable quantities of fossil plants w r ere also collected in the shale above the coal in various small mines north of Morris, but almost all these mines are now shut down. The Wilmington Star No. 7 mine in the NE. ^ of Sec. 5, T. 33 N., R. 8 E., 2J4 miles west of the Santa Fe depot in Coal City, also supplied some fossils. Another locality which still produces fossil plants from the shale above the coal is the No. 1 mine of the Spring Valley Coal Company at Spring Valley, in the SW. \i of Sec. 35, T. 16 N., R. 11 E. in Bureau County. The Skinner No. 2 mine shaft is 60 feet deep to the coal. The fossils are contained in concretions extending through about six feet of shale above the coal and excellent impressions are found directly in the shale, not more than twelve inches from the coal. No concretion^ were observed in the coal in Wilmington Star No. 7 and in the Spring Valley No. 1 mines. The fossils there are found only in the shale. The coal lies in the Wilming- 9 10 PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS ton Star mine at an average of 135 feet below the surface, except near the main shaft, where it is 185 feet deep. At Spring Valley the coal lies 360 feet below the surface. The coal seams associated with shales carrying fossil plants are com- monly called No. 2 coal in Illinois, with the local name of the "Third Vein" at La Salle and Spring Valley. For the sake of convenience, the No. 2 designation will be kept in this bulletin, although a later correlation of coal seams on the basis of fossil plants in Illinois may suggest a different number. The flora which is described from these localities is somewhat analogous to the flora of the Stephanian of Germany and France, which would indicate a stratigraphic position much higher than that of the lower Carbondale. Collections The material which is described in this bulletin was collected partly by the author and his students, and part of it is in other existing collections. The most prominent collectors during the latter part of the nineteenth century and of the present time were C. D. Young, J. C. Carr, and L. E. Daniels, all of Morris, Illinois; W. J. Knoblock, of Quincy, Illinois, and George Condie, of Spring Valley. The mine management of the Wilming- ton Star No. 2 mine also contributed a valuable specimen for this descrip- tion. Mr. C. D. Young of Morris has donated his extremely valuable col- lection to the University of Chicago. The Carr and Daniels collections were acquired by the University of Illinois and are kept in the Museum of Natural History, Urbana, Illinois. Mr. Knoblock's collection is in his home at Quincy, but a portion of it was generously lent to the University of Chi- cago for a period of time in order to be described. The collection of Mr. Condie is in his home in Spring Valley. The author wishes to express his appreciation of the assistance which he has received from Mr. F. C. Baker, Curator of the Natural History Museum, University of Illinois, who not only facilitated the study of the collection at the Museum but lent a por- tion of it for a specified time to the University of Chicago. Historical Review The literature describing the fossil flora of northern Illinois belongs to the later decades of the nineteenth and the first of the twentieth century. Volume 2 (1866) and Volume 4 (1870) of the first Geological Survey of Illinois contain numerous descriptions of fossil plants by Leo Lesquereux, the Swiss naturalist who arrived in the United States as the companion of Louis Agassiz. He was destined to become the father of paleobotany in this country, while Sir William Dawson inaugurated the same science in Canada. Lesquereux collected all available information on fossil plants of the American Carboniferous formation for Report P of the Second Geologi- cal Survey of Pennsylvania published under the title, Coal Flora of the Carboniferous Formation in Pennsylvania and Throughout the United Stales. An atlas was published in 1879, Volumes 1 and 2 of the text in 1880, and PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS 11 Volume 3, containing text and some plates, in 1884. A great many of Lesquereux's fossil plants were described again and in a few instances aug- mented by other species in a Dictionary of the Fossils of Pennsylvania and Neighboring States, compiled by J. P. Lesley (Geological Survey of Penn- sylvania Report P 4, 1889-1890). Another publication which contains illustrations and descriptions of Carboniferous plants of North America based upon determinations by Lesquereux is North American Geology and Paleontology for the Use of Amateurs, Students and Scientists, by S. A. Miller, Cincinnati, 1889. These books contain the earlier investigations of fossil plants of the Pennsylvanian in Illinois and nothing more was done along these lines until the years 1906, 1907, and 1908, when a new era of Paleozoic plant studies was inaugurated in Illinois by David White, Geologist of the United States Geological Survey, upon instigation of the State Geological Survey of Illinois. Dr. White's observations are given in Bulletins 4, 8, and 14 of the Illinois State Geological Survey. He restricted himself to a preliminary report of the distribution of Pennsylvanian plants in Illinois. It was on the basis of his observations that the subdivisions of the Pennsylvanian system in Illinois — Pottsville, Carbondale, and McLeansboro — were made. A new and third period in the study of fossil plants in Illinois began when the State Geological Survey engaged the services of the author for extensive collecting of Pennsylvanian plants throughout the State. These collections will be described in a series of reports of which this one is the first. Method of Determination All specimens of the collection were first checked against the figures of Lesquereux's Atlas of the Coal Flora of Pennsylvania. They were also compared with the Carboniferous specimens described and illustrated in the works of David White, R. Zeiller, A. Renier, C. Grand'Eury, B. Renault, H. Potonie, W. Gothan, and W. J. Jongmans. Lesquereux's nomenclature is obsolete and needs frequent corrections so that many of the species have now been relegated to the class of synonyms. His nomenclature was, therefore, corrected with the help of the above- mentioned authors and by comparing them with the species' names and synonyms listed in the catalogue of the Paleozoic plants in the Department of Geology and Paleobotany of the British Museum, by R. Kidston, London, 1886, and in the manuscript catalog of David White. Organization of the Material The organization of paleobotanic material is not as simple a matter as would be the arrangement of a living flora. The taxonomic and the biologic points of view for the classification of fossil plants frequently do not agree, and yet a purely artificial system of plants cannot be consid- ered the ideal basis for organizing such material. Therefore, the author 12 PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS has kept in mind the biologic considerations as they are expounded in the most recent general paleobotanic textbooks such as the following: Seward, A. C: Fossil Plants, 4 vol., London, 1898-1919. Berry, E. W. : Paleobotany, a Sketch of the Origin and Evolution of Floras, Washington, 1920. Potonie, H. and W. Gothan: Lehrbuch der Paleobotanik, 2nd edition, Berlin, 1921. Scott, D. H.: Studies in Fossil Plants, 3rd edition, London, 1921-23. Gothan, W.: Leitfossilien-Karbon und Perm. Pflanzen, Berlin, 1923. Scott, D. H.: Extinct Plants and Problems of Evolution, London, 1924. Acknowledgments The author wishes to express his sincere thanks to D. C. Young, the donor of a beautiful collection of fossil plants from the Mazon Creek deposits to the University of Chicago; to Ed. Carr, son of the collector, J. C. Carr, for many courtesies and numerous fossils given to the University of Chicago; to F. C. Baker, Curator of the Natural History Museum, University of Illinois, for his great kindness in facilitating the study of the Carr and Daniels collections; to W. J. Knoblock in Quincy and George Condie in Spring Valley for the loan of valuable fossils; to Dr. W. E. Walsh in Morris for specimens and valuable assistance; and to W. Oswald of Braidwood for his courtesy and help. The deepest gratitude of the author is felt toward the State Geological Survey of Illinois which has facilitated and published these studies. Special thanks are also due to the former Chief of the Survey, Mr. F. W. DeWolf, and to the present Chief, Dr. M. M. Leighton, who authorized and gener- ously supported these investigations. The author is much indebted to Dr. Harold E. Culver, who was in charge of the coal investigations of the Illinois State Geological Survey and who gave invaluable aid throughout the investigation. To Dr. David White, who has critically read this report and offered most valuable suggestions, the author wishes to express his sincere appreciation. IDENTIFICATION OF FOSSIL PLANTS Definition of a Fossil Plant Species In order to identify and classify fossil plants, it is important to have in mind what a fossil species is. It is more difficult to distinguish fossil plant species which are fragmentary than to recognize living plant species where complete specimens are available. It has occurred frequently that two fossil leaf forms have been described as representing two distinct species and similar forms were later found connected on one single branch. Such fossils as show characteristic differences and have never been found to have grown on one and the same plant should be considered as differ- ent species. If we keep in mind the pronounced polymorphism of many organs in living plants, and assume that similar conditions prevailed in the Paleozoic era, we must conclude that our species distinctions of fossil plants are only approximately true and subject to constant revision upon the discovery of more complete material. It also follows that the better known species present a wider range of variations than those of which we know little. Furthermore, we know most fossil plant species only from impressions and PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS 13 must base our species descriptions on few and often secondary charac- ters. We have form types of this case — such as, stem types, leaf types, and fructification types. Only in comparatively few instances do we possess petrefacts with well preserved tissues and, under favorable circumstances, can we establish phylogenetic, that is, evolutionary relations and distinc-. tions. Under such favorable but rare circumstances we actually have biological species types of the same value as offered by living plants. The plants that are figured in this report fall under the following general groups: 1. Equisetales 2. Sphenophyllales 3. Lycopodiales 4. Filicales 5. Cycadofilicales 6. Cordaitales Groups 1 to 4 inclusive belong to the general phylum of Pteridophytes, while groups 5 and 6 belong to the Gymnosperms of the Spermatophytes. No Angiosperm impressions were recognized in the Paleozoic era, although they probably existed, because Angiosperm-like structures were found in coal balls from the Pennsylvanian of Illinois 1 . The six groups mentioned above, with the exception of the Filicales, represent truly phylogenetic divisions of the plant kingdom. Originally all fern-like fossil leaves were classed as true ferns until many of them were found connected with Gymnosperm-like seeds. Early in the twentieth century the Cycadofilicales or seed fern group was established and was joined to the Gymnosperms. Since in most cases we deal with fern-like leaf impressions which may phylogenetically belong either to Pteridophy- tes or Gymnosperms, the most convenient form of classification may be Filicales or, as Potonie had suggested, Pteridophylls. As the latter name has not yet been introduced in this country, we may still be permitted to call the group Filicales, but it must be kept in mind that the fossils classified under this name are only a form group, an assemblage of leaf types, which may belong to true ferns or to seed ferns or, in some instances, to both. List of Figured Species The following forms, classified according to the various groups, were found in northern Illinois and are illustrated in Plates I to XLV: Equisetales: Calamites suckowi Brongniart Annularia stellata (Schlotheim) Wood A. radiata (Brongniart) Sternberg A. sphenophylloides (Zenker) Gutbier Calamocladus equisetiformis (Schlotheim) Schimper Calamostachys solmsi (Weiss) Weiss C. germanica Weiss C. magna Lesquereux Joskins, J. H., A Paleozoic Angiosperm from an American coal ball; Botanical Gazette: pp. .590- .597, 1923 Noe, A. C, A Paleozoic Angiosperm; Journal of Geology: Vol. xxi, No. 4, pp. 34-4-^47, 1923. 14 PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS Sphenoph y Hales : Sphenophyllum emarginatum (Brongniart) Koenig S. majus (Bronn) Bronn Lycopodiales: Lepidodendron lanceolatum Lesquereux L. latifolium Lesquereux L. wortheni Lesquereux L. rigens Lesquereux Lepidophyllum majus Brongniart Lepidostrobus communis Lindley and Hutton Lepidostrobus ovatifolius Lesquereux Lepidophloios protuberans Lesquereux Lycopodites meekii Lesquereux Syringodendron porteri Lesquereux Sigillaria camptotoenia (Wood) Wood Stigmaria ficoides (Sternberg) Brongniart Filicales: 1. Sphenopteridae: Sphenopteris gracilis (Brongniart) Presl S. capitata White S. chaerophylloides (Brongniart) Presl Palmatopteris furcata (Brongniart) Potonie 2. Megalopteridae: Megalopteris southwellii Lesquereux 3. Mariopteridae: Mariopteris muricata (Schlotheim) Zeiller Mariopteris muricata var. nervosa (Schlotheim) Zeiller Mariopteris mazoniana (Lesquereux) White 4. Neuropteridae: Neuropteris rarinervis Bunbery Cyclopteris orbicularis Brongniart Neuropteris flexuosa Sternberg N. clarksoni Lesquereux N. ovata Hoffmann N. crenulata Brongniart N. capitata Lesquereux N. oblongifolia Gutbier N. vermicularis Lesquereux N. decipiens Lesquereux 5. Linopteridae: Linopteris neuropteroides (Gutbier) Potonie 6. Pecopteridae: Pecopteris vestita Lesquereux P. pseudovestita White P. miltoni Artis P. squamosa Lesquereux PENNSYLVANIA^ FLORA OF NORTHERN ILLINOIS 15 P. arborescens (Brongniart) Sternberg P. pennaeformis (Brongniart) Sternberg P. dentata Brongniart P. unita Brongniart Ptyehocarpus unita (Brongniart) Weiss 7. Odontopteridae: Odontopteris subcuneata Bunbery O. wortheni Lesquereux 8. Alethopteridae: Alethopteris serlii (Brongniart) Goeppert A. davreuxi (Brongniart) Goeppert A. grandini (Brongniart) Goeppert 9. Callipteridae: Callipteridium sullivanti (Lesquereux) Weiss 10. Fern stems: Megaphyton spec. Ptychopteris spec. Cycadofilicales and Cordaitales: Staphylopteris sagittatus Lesquereux Codonotheca caduca Sellards Codonospermum anomalum Brongniart Tripterospermum rostratum Brongniart Trigonocarpum noeggerathi Sternberg Pachytesta incrassata Brongniart Cardiocarpus orbicularis Ettingshausen Cordaitales: Cordaites grandifolius Lesquereux Cordaianthus gemmifer Grand Eury DISCUSSION OF FIGURED ORDERS AND GENERA Equisetales The Paleozoic Equisetales, remnants of which are preserved, must have been arborescent forms. Undoubtedly, herbaceous species, from which our modern Equisetum descended, must also have existed. The name, Calamites, always designates a stem form. Independently, leaves and smaller branches were found which were called Annularia or Calamocladus and fructifications, which were named Calamostachys. These are, there- fore, not biological genus names but form types, because a Calamites, an Annularia, and a Calamostachys grew on the same individual plant. How- ever, it is not known, except in very few instances, which species of these genera belonged together. For practical purposes, particularly for use as stratigraphic index fossils, it is immaterial to know how they were com- bined. The biological paleobotanist or, better called, fossil plant morpholo- gist would, of course, like to know more of these combinations in order to explain the phylogeny of the Paleozoic Equisetales, but in order to study this aspect with hope of success it will be necessary to obtain a great deal more material, especially petrified or coal ball specimens. 16 PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS Sphenophyllales This order contains only one genus, Sphenophyllum, and that is now extinct. We know nothing about any relation of the Paleozoic Sphenophyl- lales with living plants. Sphenophyllum was an aquatic and herbaceous plant, had jointed stems with whirls of triangular leaves that always appeared in multiples of three. At the end of the branches were the long and narrow strobili. Lycopodiales Probably most of the known genera and species of fossil Lycopodiales were arborescent, with the exception of the genus Lycopodites, which was herbaceous. There must have been numerous herbaceous Lycopodiales in the Paleozoic era from which our living Lycopodiales descended. The large tree forms died out almost entirely at the end of the Paleozoic era, but a few medium-sized Mesozoic tree types persisted for a short time. The two principal genera of the Paleozoic era are Lepidodendron and Sigillaria, both of which reached a height of about one hundred feet. Lepidodendron is the generic name for a stem type that had spirally arranged rhomboidal leaf scars, whereas Sigillaria had its leaf scars ver- tically arranged. Syringodendron was a Sigillaria whose cortex had been removed before fossilization. Lepidostrobus is the generic name for the strobilus or cone of Lepidodendron. Lepidophyllum is the scale of Lepido- strobus, and Stigmaria designates a root form that might have belonged to a Lepidodendron or a Sigillaria stem. The different species of Lepidoden- dron and Sigillaria are distinguished by the shape of their leaf cushions. Leaves seem to have been born only on the youngest branches of these trees, but the leaf cushions continued to grow on the stem and on the older branches after the leaves had fallen off and formed a sort of armor around the tree similar in function to the armor of some living Cycads but differing in the shape of their leaf scars. The leaf scars of Lepidophloios were more broad than long, whereas those of Lepidodendron were more long than broad. Lycopodites was a herbaceous type, similar to the modern genera Selaginella and Lycopodium. The root form of Lepidodendron and Sigillaria, Stigmaria ficoides, was covered with small rootlets of which the circular scars are still visible. Filicales The mo^t numerous and stratigraphically most useful plant fossils of the Paleozoic sediments are impressions of fern-like leaves. A large number, perhaps the majority of them, did not belong to true ferns but were parts of trees that had the habitus of tree ferns and the fructifications of Gymnosperms. This extinct group which seemed to have sprung from the same origin as the true ferns has been discovered only during the early twentieth century and in America is called Cycadofilicales. English paleobotanists use the name Pteridosperms, a Greek translation for seed- ferns. The fructifications of these Cvcadofilicales will be discussed later. PENNSYLVANIAN FLORA 01 NORTHERN ILLINOIS 17 As mentioned in an earlier chapter, the group name Filicales is still used in this report for the fern-like impressions. For two very characteristic fern stem types the generic names of Megaphyton and Ptychopteris are used. They are marked by very large leaf scars which were produced after the leaf stems or petioles had fallen Off. The fern-like leaves are divided into genera according to the following characters: a. The form of attachment of the smallest leaf units (pinnules) to the stem that bears them. b. The general shape of the pinnules and their arrangement and de- velopment in the fronds. c. The venation of the pinnules. On the basis of these distinctions we have arranged our material into the following genera: 1. Sphenopteris. The pinnule is contracted at its base and is lobed or dissected. Some Sphenopteris species were Cycadofilicales. 2. Palmatopteris. This genus resembles Sphenopteris but has very deeply dissected pinnules. It is a Cycadofilicales. 3. Megalopteris. This is a large-leafed fern type with a simple pin- nate frond and was probably herbaceous. It is rarely found and occurs only in the Pottsville formation. It is present in the Rock Island district. It is a Cycadofilicales. 4. Mariopteris. This genus has a large frond that is divided many times. Its pinnules have a broad base and arch-shaped secondary veins projecting from the base of the pinnule. Frequently no midrib is visible. It is a Cycadofilicales. 5. Neuropteris. Pinnules have a narrow base from which arch-shaped veins emerge. There is usually a midrib. The veins fork dichotomously from one to several times but are not connected. At the base of the com- posite frond are rounded leaves with a radiating venation. These leaves were originally called Cyclopteris and were considered as belonging to a distinct genus. For the sake of convenience, this name has been retained to characterize such types of leaves. 6. Linopteris. The shape of the pinnule is exactly like that of Neurop- teris, but the veins are anastomosed and form a net. It is a Cycadofilicales. 7. Pecopteris. A large number of species belong to this genus which is especially w r ell represented in the higher strata of the Pennsylvanian. The pinnules are generally small and possess a distinct midrib usually with few secondary veins and a broad base. The name Asterotheca and Ptycho- carpus are used for certain Pecopteris forms which show spore capsules. 8. Odontopteris. This genus has a pinnule like Pecopteris except that there is no midrib and the veins enter parallel from the base. It is a Cycado- filicales. 9. Alethopteris. The pinnules also have a broad attachment, but their bases are decurrent. The midrib is always very distinct and the secondary veins numerous. It is a Cycadofilicales. 18 PENNSYLVANIAN FLORA OF NORTHERN ILLINOIS 10. Callipteridium. This differs primarily by its broad, bluntly ending pinnules from Alethopteris. In Europe Callipteridium is an index fossil of Permian and Sub-Permian strata. It is a Cycadofilicales. Some basal leaves of fern-like fronds are called Aphlebiae. Sometimes young leaves which are still coiled are found. Although the generic name, Spiropteris, is well suited to these forms, it seems rather useless to dis- tinguish species, for every individual fossil of this kind would have to re- ceive a species name. The only true ferns (Filicales) among the leaf impressions found at Mazon Creek and Braidwood belong to the genera Sphenopteris and Pecopteris. Cycadofilicales Numerous seeds of gymnospermic character but associated with fern- like leaves, such as Codonospermum, Tripterospermum, Pachytesta, Stephanospermum, Trigonocarpum are known. Codonotheca, which was first found by E. H. Sellards in Illinois and described by him, is probably a microspore-bearing organ of Neuropteris. Staphylopteris may have had the same function but was associated with Sphenopteris. CORDAITALES These were gymnospermic trees with tall shafts whose branches bore tufts of very large ribbon-shaped leaves. The male reproductive organs of this order received the generic name of Cordaianthus, the female, that of Cardiocarpus, and the leaves that of Cordaites. PART II.— EXPLANATION OF PLATES Note: Objects are reproduced in natural size except where otherwise indicated. Abbreviations for Collections U C Coll.- Collection in Walker Museum of the Uni- versity of Chicago U I Coll.- Collection in the Museum of Natural His- tory, University of Illinois K Coll.- Collection of Wilbur T. Knoblock, 1901 Ohio St., Quincy, Illinois C Coll.- Collection of George Condie, 320 E. Erie St., Spring Valley, Illinois 19 Illinois State Geological Survey Bulletin No. 52, Plate I • if* £ 20 Plate II. EQUISETALES The surviving genus of this great Paleozoic order is Equisetum, a herbaceous plant growing along creeks and in damp meadows. It is commonly called Horse Tail or Scouring Rush. In Pennsylvanian times tree forms of this order grew. Their stems are called Calamites, their leaves Annularia, or if smaller and more numerous Calamocladus, their fructifications Calamostachys. (See Plates II to V.) 1. Calamites suckowi Brongniart, from La Salle, x 1/5, U C Coll. No. 32000. 2. Calamostachys solmsi (Weiss) Weiss, from Braidwood, U C Coll. No. 32001. 3. Calamites suckowi Brongniart, from Braidwood, x 2/3 U C Coll. No. 32002. 22 Illinois State Geological Survey 1 Bi LLETIN No. 52, Plate II 23 Plate III. EQUISETALES 1 5. Annularia stellata (Schlotheim) Wood. 1,2, and 4. From Mazon Creek, U. C. Coll. No. 32003. 3 and 5. From Braidwood, U I Coll. No. P 1281. 24 Illinois State Geological Survey Bulletin No. 52, Plate 1 1 1 25 Plate IV. EQUISETALES Calamocladus equisetiformis (Schlotheim) Schimper, from Morris, III., x 2 '3, U I Coll. No. P 1282. Annularia radiata (Brongniart) Sternberg. On branches of a Calamites stem, from Mazon Creek, x 2/3, U I Coll. No. P 1283. 26 Illinois State Geological Surve\ Bulle 1 1\ No. 52, Plate IV 27 Plate V. EQUISETALES 1. Annularia radiata (Brongniart) Sternberg, from Mazon Creek, U C Coll. No. 32004. 2. Annularia sphenophylloides (Zenker) Gutbier, from Mazon Creek, U C Coll. No. 32005. 3. Annularia sphenophylloides (Zenker) Gutbier, from Braidwood, U C Coll. No. 32006. 4. Calamostachys germanica Weiss (The strobilus of Calamocladus equisetiformis Schl.), from Braidwood, U C Coll. No. 32007. 5. Calamostachys magna Lesquereux, from Mazon Creek, x 2/3 U I Coll. No. P 1284. 28 Illinois State Geological Survey Bulletin No. 52, Plan V 29 Plate VI. SPHENOPHYLLALES These grew in brooklets and had floating stems and wedge-shaped leaves as denoted by the Greek name Spheno- phyllum. No living relatives of this Paleozoic plant order are known. 1. Sphenophyllum majus (Bronn) Bronn, from Mazon Creek, U C Coll. No. 32008. 2. Sphenophyllum stem, from Braidwood, x 2/3, U C Coll. No. 32009. 3-6. Sphenophyllum emarginatum (Brongniart) Koenig, from Braid- wood, U C Coll. No. 32074, No. 32089, and No. 32090. 30 Illinois State Geological Sikvky 1 Bulletin No. 52, Plate VI 31 Plate VII. LYCOPODIALES The surviving genera of this order are our present day club mosses Lycopodium and Selaginella. From the Penn- sylvanian are known tree forms Lepidodendron, Lepido- phloios, and Sigillaria, and a herbaceous type Lycopodites. Syringodendron is the name for a Sigillaria type which had lost its characteristic bark before fossilization. Lepi- dostrobus is the fructification of Lepidodendron. Stig- maria is the name for the roots of Lepidodendron and Sigillaria. (See Plates VII to XII.) 1. Lepidostrobus ovatifolius Lesquereux (cone of Lepidodendron). 2. Lepidodendron lanceolatum Lesquereux. 3. Lepidostrobus communis Lindley and Hutton. 4. Lepidodendron latifolium Lesquereux. All are from Mazon Creek, K Coll. 32 Illinois State Geological Survey Bulletin No. 52, Plate VII ' mm m m \ 33 Plate VIII. LYCOPODIALES 1. Lepidophloios protuberans Lesquereux, from Braidwood, U C Coll. No. 32010. 2. Lepidodendron Wortheni Lesquereux, from Mazon Creek, U C Coll. No. 32011. 3. Lepidodendron latifolium Lesquereux, from Mazon Creek, U C Coll. No. 32012. 34 Illinois State Geological Survey Bulletin No. 52, Plate VIII 1% \>,i ■> V A ' ■ 1> r ■ 35 Plate IX. LYCOPODIALES Lepidodendron rigens Lesquereux, from Mazon Creek, U C Coll. No. 32013. 36 Illinois State Geologh u. Si rvey Bulletin No. 52, Plate IX 37 Plate X. LYCOPODIALES 1. Lycopodites Meekii Lesquereux, from Mazon Creek, U I Coll. No. P 1285. 2-3. Lepidophyllum majus Brongniart, from Mazon Creek, x 2/1, U C Coll. No. 32014. 4. Lycopodites Meekii Lesquereux, from Mazon Creek, x 2/3, U C Coll. No. 32015. 38 Illinois State Geological Survey Bui LETIN No. 52, Plate X 3 39 Plate XI. LYCOPODIALES 1. Sigillaria camptotaenia (Wood) Wood, from Braidwood, U C Coll. No. 32016. 2. Syrtngodendron porteri Lesquereux, from Braid-wood, x 1/2, U C Coll. No. 32017. 3. Sigillaria camptotaenia (Wood) Wood, from Braidwood, U C Coll. No. 32018. 40 Illinois State Geological Si k\ e \ Bulletin No. 52, Plate XI 41 Plate XII. LYCOPODIALES 1-3. Stigmaria ficoides (Sternberg) Brongniart, from Braidwood, x 2/3, U C Coll. No. 32019, No. 32079, and No. 32080. 42 h i i\ois State Geological Survey Bulletin No. 52, Plate XII <£ 43 Plate XIII. FILICALES: SPHENOPTERIDAE Here belong such leaf impressions as might have grown on true herbaceous fern plants, on tree-ferns, and on so- called seed-ferns or Cycadofilicales. The latter are an ex- tinct type of Gymnosperms with fern-like foliage and cycad-like fructifications. They formed a link between ferns and cycads in evolution. In this publication all fern- like leaves are listed under Filicales and all Cycadofilicales- seeds under Cycadofilicales. Stems of true ferns were found and are pictured in this bulletin under the generic names Megaphyton and Ptychopteris. (See Plates XIII to XIV.) 1. Palmatopteris furcata (Brongniart) Potonie, from Braidwood, U C Coll. No. 32020. 2. Sphenopteris gracilis Brongniart, from Mazon Creek, U C Coll. No. 32021. 3. Sphenopteris capitata White, from Braidwood, U C Coll. No. 32022. 44 Illinois State Geological Survey Bulletin No. 52, Plate XIII 45 Plate XIV. FILICALES: SPHENOPTERIDAE Sphenopteris chaerophylloides (Brongniart) Presl, from Mazon Creek, U C Coll. No. 32023. 46 Illinois State Geological Survey Bulletin No. 52, Plate XIV 47 Plate XV. FILICALES: MEGALOPTERIDAE Megalopteris southvvellii Lesquereux, from Port Byron, Collec- tion of Davenport (Iowa) Academy of Science. 48 Illinois State Geological Survey Bulletin No. 52, Plate XV 5S I 49 Plate XVI. FILICALES: MARIOPTERIDAE 1. Mariopteris muricata var. nervosa (Schlotheim) Zeiller, from Mazon Creek, U C Coll. No. 32024. 2-3. Mariopteris muricata (Schlotheim) Zeiller, from Mazon Creek, U I Coll. No. P 1286 and No. P 1317. 4. mariopteris mazoniana (Lesquereux) White, from Braidwood, U C Coll. No. 32025. 5. Mariopteris muricata var. nervosa (Schlotheim) Zeiller, from Braidwood, U C Coll. No. 32081. 50 Illinois State Geological Survey Bulletin No. 52, Plate XVI 51 Plate XVII. FILICALES: NEUROPTERIDAE 1-3. Neuropteris rarinervis Bunbery. 1. From Spring Valley, x 1/2, C Coll. 2. From Mazon Creek, x 2/3, U I Coll. No. P 1287. 3. From Spring Valley, x 1/3, C Coll. 52 Illinois State Geological Survey Bulletin No. 52, Plate XVII *Sa 53 Plate XVIII. FILICALES: NEUROPTERIDAE 1-3. Neuropteris rarinervis Bunbery. 1. From Mazon Creek, U C Coll. No. 32088. 2. From Mazon Creek, x 1/2, U I Coll. No. P 1288. 3. From Braidwood, U C Coll. No. 32026. 54 Illinois State Geological Survey Bulletin No. 52, Plate XVIII 55 Plate XIX. FILICALES: NEUROPTERIDAE 1-2. Cyclopteris orbicularis Brongniart, from Braidwood, U C Coll. No. 32027 and No. 32082. 56 Illinois State Geological Survey Bulletin No. 52, Plate XIX 57 Plate XX. FILICALES: NEUROPTERIDAE 1. Neuropteris flexuosa Sternberg, from Mazon Creek, U C Coll. No. 32028. 2. Neuropteris clarksoni Lesquereux, from Mazon Creek, x 2/3, U C Coll. No. 32029. 3. Neuropteris ovata Hoffmann, from Mazon Creek, U C Coll. No. 32030. 58 Illinois State Geological Survey Bulletin No. 52, Plate XX 59 Plate XXI. FILICALES: NEUROPTERIDAE 1. Neuropteris clarksoni Lesquereux, from Mazon Creek, x 1/2, U C Coll. No. 32031. 2-3. Neuropteris flexuosa Sternberg, from Mazon Creek, x 2/3, U C Coll. No. 32032 and No. 32083. 4. Neuropteris ovata Hoffman, from Mazon Creek, x 2/3, U I Coll. No. P 1289. 5. Neuropteris crenulata Brongniart, from Mazon Creek, x 2/3, U I Coll. No. P 1290. 60 Illinois State Geological Survey l Bulletin No. 52, Plate XXI Ik 61 Plate XXII. FILICALES: NEUROPTERIDAE and LINOPTERIDAE 1-3. Neuropteris capitata Lesquereux. 1. Ultimate pinnule from Mazon Creek, U I Coll. No. P 1291. 2-3. From Mazon Creek, U C Coll. No. 32033 and No. 32084. 4. Linopteris neuropteroides (Gutbier) Potonie, from Mazon Creek, U I Coll. No. P 1292. 62 Illinois State Geological Survey Bulletin No. 52, Plate XXII 63 Plate XXIII. FILICALES: NEUROPTERIDAE and LINOPTERIDAE 1. Linopteris neuropteroides (Gutbier) Potonie, from Mazon Creek, U I Coll. No. P 1293. 2. Neuropteris oblongifolia Gutbier, from Mazon Creek, U I Coll. No. P 1294. 3. Neuropteris flexuosa Sternberg, from Mazon Creek, K Coll. 64 Illinois State Geological Survey Bulletin No. 52, Plate XXIII 65 Plate XXIV. FILICALES: NEUROPTERIDAE 1. Neuropteris vermicularis Lesquereux, from Mazon Creek, x 5/4, K Coll. 2-4. Neuropteris decipiens Lesquereux. 2. From Mazon Creek, x 2/5, U I Coll. No. P 1296. 3. From Braidwood, U C Coll. No. 32034. 4. From Mazon Creek, x 3/2, U C Coll. No. 32035. 66 Illinois State Geological Survey Bulletin No. 52, Plate XXIV 67 Plate XXV. FILICALES: NEUROPTERIDAE 1-3. Neuropteris decipiens Lesquereux. 1. From Braidwood, U C Coll. No. 32035. 2-3. From Mazon Creek, x 2/5, K Coll. OS Illinois State Geological Survey Bulletin No. 52, Plate XXV 69 Plate XXVI. FILICALES: NEUROPTERIDAE 1-4. Neuropteris decipiens Lesquereux. 1. Cyclopteroid leaf, from Mazon Creek, x 6/5, U I Coll. No. P 1297. 2. From Mazon Creek, x 9/10, U I Coll. No. P 1298. 3. Cyclopteroid leaf, from Mazon Creek, U C Coll. No. 32036. 4. From Mazon Creek, U I Coll. No. P 1299. 70 Illinois State Geological Survey Bulletin No. 52, Plate XXVI 71 Plate XXVII. FILICALES: NEUROPTERIDAE 1-2. Neuropteris decipiens Lesquereux. 1. From Mazon Creek, K Coll. 2. From Mazon Creek, x 3/2, K Coll. 3. Neuropteris rarinervis Bunbery, Cycloperoid leaf, from Braid- wood, x 6/5, U C Coll. No. 32037. 11 Illinois State Geological Survey Bulletin No. 52, Plate XX\ II 73 Plate XXVIII. FILICALES: VARIOUS LEAF TYPES 1. Aphlebia leaf. 2. Neuropteris decipiens Lesquereux. Cyclopteroid leaf. 3-4. Spiropteris leaves, young and rolled leaves. 5. Neuropteris decipiens Lesquereux, Cyclopteroid leaf. All from Mazon Creek, U C Coll. No. 32038-42. 74 Illinois State Geological Survey Bulletin No. 52, Plate XXVI 1 1 3 Plate XXIX. FILICALES: PECOPTERIDAE 1. Pecopteris pseudovestita White, from Mazon Creek, U C Coll. No. 32043. 2. Pecopteris vestita Lesquereux, from Mazon Creek, U C Coll. No. 32044. 3. Pecopteris vestita Lesquereux, from Mazon Creek, x 1/2, U C Coll. No. 32045. 76 Illinois State Geological Survey Bulletin No. 52, Plate XXIX W& *$ 77 Plate XXX. FILICALES: PECOPTERIDAE 1. Pecopteris MILTONI Artis, from Mazon Creek, U C Coll. No. 32047. 2. Pecopteris vestita Lesquereux, from Mazon Creek, U I Coll. No. P 1301. 3. Pecopteris squamosa Lesquereux, from Mazon Creek, U I Col!. No. P 1302. 78 Illinois State Geological Survey Bulletin No. 52, Plate XXX 79 Plate XXXI. FILICALES: PECOPTERIDAE 1-2. Pecopteris arborescens (Brongniart) Sternberg from Mazon Creek. U I Coll. No. P 1303-4. 80 Illinois STATE GEOLOGICAL Si k\ i:\ 1 Bulletin No. 52, Plate XXXI 81 Plate XXXII. FILICALES: PECOPTERIDAE Pecopteris pennaeformis (Brongniart) Sternberg, from Braidwood, U C Coll. No. 32048. S2 Illinois State Geological Survey Bulletin No. 52, Plate XXXII 83 Plate XXXIII. FILICALES: PECOPTERIDAE Pecopteris DENTATA Brorigniart, from Morris, x 2/1, I" I Coll. No. P 1305. 84 Illinois State Geological Survey Bulletin No. 52, Plate XXXIII 85 Plate XXXIV. FILICALES: PECOPTERIDAE 1. Pecopteris unita Brongniart, from Mazon Creek, U I Coll. No. P 1300. 2. The same, x 3/1. 3. Pecopteris miltoni Artis, from Mazon Creek, K Coll. 4. Pecopteris miltoni Artis, from Mazon Creek, U C Coll. No. 32046. 86 Illinois State Geological Survey Bulletin No. 52, Plate XXXIV Plate XXXV. FILICALES: PECOPTERIDAE 1-2. Pecopteris unita Brongniart, from Mazon Creek, U I Coll. No. P 1306-7. 88 Illinois State Geological Survey Bulletin No. 52, Plate XXXV •^d#- ( 89 Plate XXXVI. FILICALES: PECOPTERIDAE 1-4. Ptychocarpus unita (Brongniart) Weiss, with sori. Nos. 1, 3, and 4. From Mazon Creek, U C Coll. No. 32049-51. No. 2. From Mazon Creek, x 2/l, U C Coll. No. 32087. 90 Illinois State Geological Survey Bulletin No. 52, Plate XXXVI 91 Plate XXXVII. FILICALES: ODONTOPTERIDAE 1-2. Odontopteris subcuneata Bunbery, from Mazon Creek, U C Coll. No. 32052-3. 3-4. Odontopteris wortheni Lesquereux, from Mazon Creek, U C Coll. No. 32054-5. 92 Illinois State Geological Surve\ l'»i lletin No. 52, Plate XXXVII 93 Plate XXXVIII. FILICALES: ALETHOPTERIDAE 1-2. Alethopteris serlii (Brongniart) Goeppert, from Mazon Creek, U C Coll. No. 32056-7. 3-4. Alethopteris serlii (Brongniart) Goeppert, from Braidwood, U C Coll. No. 32058-9. 94 Illinois State Geological Survey Bulletin No. 52, Plate XXXVIII 95 Plate XXXIX. FILICALES: ALETHOPTERIDAE 1. Alethopteris davreuxi (Brongniart) Goeppert, from Mazon Creek, U I Coll. No. P 1308. 2. Alethopteris serlii (Brongniart) Goeppert, from Mazon Creek, U C Coll. No. 32060. 3--J. Alethopteris serlii (Brongniart) Goeppert, from Mazon Creek, K Coll. 96 lnois State Geological Survey Bulletin No. 52, Plate XXXIX 07 Plate XL. FILICALES: ALETHOPTERIDAE 1-2. Alethopteris grandini (Brongniart) Goeppert, from Mazon Creek, U I Coll. No. P 1309-10. 98 Illinois State Geological Survey Bulletin No. 52, Plate XL 99 Plate XLI. FILICALES: CALLIPTERIDAE 1-4. Callipteridium sullivanti (Lesquereux) Weiss. 1, 4. From Mazon Creek, U I Coll. No. P 1311-12. 2, 3. From Mazon Creek, U C Coll. No. 32061-2. 100 Illinois State GEOLOGICAL SURVEY Bulletin No. 52, Plate XLI 101 Plate XLII. CYCADOFILICALES: REPRODUCTIVE ORGANS 1-4. Staphylopteris sagittatus Lesquereux, from Mazon Creek, U C Coll. No. 32063-6. 102 Illinois State Geological Survey Bulletin No. 52, Plate XLII 103 Plate XLIII. CYCADOFILICALES: REPRODUCTIVE ORGANS 1-3. Codonotheca caduca Sellards, from Mazon Creek, x 2/1, U I Coll. No. P 1313, P 1318, P 1319. 4. Codonospermum anomalum Brongniart, from Braidwood, U C Coll. No. 32067. 5. Tripterospermum rostratum Brongniart, from Braidwood U C Coll. No. 32086. 104 Illinois State Geological Survey Bulletin No. 52, Plate XLIII 105 Plate XLIV. CYCADOFILTCALES AND CORDAITALES: REPRODUCTIVE ORGANS 1-2. Tripterospermum rostratum Brongniart, from Braidwood, U C Coll. No. 32068. 3. Cardiocarpus orbicularis Ettingshausen, x 2/1, from Mazon Creek, K Coll. 4. Pachytesta incrassata Brongniart, from Braid-vcood, U C Coll. No. 32069. 5. Trigonocarpum noeggerathi Sternberg, from Mazon Creek, x 2/1, K Coll. 106 Illinois State Geological Survey Bulletin No. 52, Plate XLIV 107 Plate XLV. CYCADOFILICALES, CORDAITALES, AND FERN STEMS An extinct class of Paleozoic Gymnosperms is named Cordaitales in honor of the great paleobotanist Corda. Leaves, stems, and the reproductive organs have been found. The leaves belong to the genus Cordaites, the male reproductive organs to Cordaianthus and the seeds to Cardiocarpus. Specimens are illustrated in Plate XLV, figs. 2 and 3. 1. Staphyllopteris sagittatus Lesquereux, from Mazon Creek, K Coll. 2. Cordaites grandifolius Lesquereux, from Mazon Creek, x 1/2, U C Coll. No. 32071. 3. Cordaianthus gemmifer Grand ' Eury, from Mazon Creek, U C Coll. No. 32072. 4. Megaphyton spec, from Braidwood, x 3/1, U C Coll. No. 32073. 5. Ptychopteris spec, from Coal City Willmington Star Coal Mining Co., Mine No. 7, x 3/1, Property of Mining Company. 108 Illinois State Geological Si rvei Bulletin No. 52, Plate XLV 109 INDEX PAGE A Acknowledgments 12 Alethopteridae 15, 94-99 Alethopteris 17 davreuxi (Brongniart) Goeppert.. 15, 96-97 grandini (Brongniart) Goeppert.. 15, 98-99 serlii (Brongniart) Goeppert 15, 94-95, 96-97 Annularia 15 radiata (Brongniart) Sternberg.. . 13, 26-29 sphenophylloides (Zenker) Gut- bier 13, 28-29 stellata (Schlotheim) Wood.. .13, 24-25 Aphlebiae 18, 74 Asterotheca 17 B Baker, F. C., cooperation of 10, 12 Braidwood, fossils from vicinity of . . 9, 22-23, 24-25, 28-29, 30-31, 34-35, 40-45, 50-51, 54-57, 66-67, 68-69, 72-73, 82-83, 95-96, 104-105, 106- 107 C Calamites 15 suckowi Brongniart 13, 22-23 Calamocladus 15 equisetiformis (Schlotheim) Schimper 13, 26-27 Calamostachys 15 germanica Weiss 13, 28-29 magna Lesquereux 13, 28-29 solmsi (Weiss) Weiss 13, 22-23 Callipteridae 15, 100-101 Callipteridium 18 sullivanti (Lesquereux) Weiss. . . 15, 100-101 Cardiocarpus 18 orbicularis Ettingshausen . . 15, 106-107 Carr, Ed., cooperation of 12 Carr, J. C., fossils collected by 10, 12 Classification of fossil plants. . .11-12, 13 Coal City, fossil plants from mine near 9 fossils from vicinity of 108-109 PAGE Codonospermum 18 anomalum Brongniart 15, 104-105 Codonotheca 18 caduca Sellards 15, 104-105 Condie, George, fossils collected by. 10, 12 Cordaianthus 18 gemmifer Grand ' Eury .... 15, 108-109 Cordaitales 15, 18, 106-109 Cordaites 18 grandifolius Lesquereux. ... 15, 108-109 Culver, H. E., assistance of 12 Cycadofilicales 15, 16-17, 18, 102-109 Cyclopteris 17 orbicularis Brongniart 14, 56-57 D Daniels, L. E., fossils collected by. 10, 12 Dawson, William, work of 10 De Wolf, F. W., cooperation of . . . . 12 E Equisetales 13, 15, 22-29 F Fern stems 15, 108-109 Filicales 14, 16-18, 44-101 Fossil plants, classification of 11-12 identification of 12-15 Fossil species, definition of 12-13 H Historical review 10-1 1 I Introduction 9-12 K Kidston, R., work of 11 Knoblock, W. J., fossils collected by. 10, 12 LaSalle, fossils from vicinity of. . . .22-23 Leighton, M. M., cooperation of. . . 12 Lepidodendron 16 lanceolatum Lesquereux 14, 32-33 111 112 INDEX— Continued PAGE latifolium Lesquereux. 14, 32-33, 34-35 rigens Lesquereux 14, 36-37 wortheni Lesquereux 14, 34-35 Lepidophloios 16 protuberans Lesquereux 14, 34-35 Lepidophyllum 16 majus Brongniart 14, 38-39 Lepidostrobus 16 communis Lindley and Hutton. . 14, 32-33 ovatifolius Lesquereux 14, 32-33 Lesley, J. P., work of 11 Lesquereux, Leo, work of 3, 10-11 Linopteridae 14 Linopteris 17 neuropteroides (Gutbier) Potonie 14, 62-63, 64-65 Location of area 9-10 Lycopodiales 14, 16, 32-43 Lycopodites 16 meekii Lesquereux 14, 38-39 M Mariopteridae 14, 50-51 Mariopteris 17 mazoniana (Lesquereux) White . . 14, 50-51 muricata (Schlotheim) Zeiller. . . . 14, 50-51 muricata var. nervosa (Schlot- heim) Zeiller 14, 50-51 Mazon Creek, fossils from vicinity of 9, 24-25, 26-27, 28-29, 30-31, 32-33, 34-39, 44-45, 46-47, 50-51, 52-53, 54-55, 58-67, 68-73, 74-81, 86-95, 96-105, 106-107, 108-109 Megalopteridae 14, 48-49 Megalopteris 17 southwellii Lesquereux 14, 48-49 Megaphyton spec 15, 17, 108-109 Miller, S. A., work of 11 Morris, fossils from vicinity of . . . . 9, 26-27, 84-85 N Neuropteridae 14, 52-75 Neuropteris 17 capitata Lesquereux 14, 62-63 clarksoni Lesquereux. .14, 58-59, 60-61 crenulata Brongniart 14, 60-61 decipiens Lesquereux 14, 66-75 flexuosa Sternberg 14, 58-59, 60-61, 64-65 oblongifolia Gutbier 14, 64-65 PAGE ovata Hoffmann 14, 58-59, 60-61 rarinervis Bunbery 14, 52-55, 72-73 vermicularis Lesquereux 14, 66-67 O Odontopteridae 15, 92-93 Odontopteris 17 subcuneata Bunbery 15, 92-93 wortheni Lesquereux 15, 92-93 Oswald, W., cooperation of 12 Pachytesta 18 incrassata Brongniart 15, 106-107 Palmatopteris 17 furcata (Brongniart) Potonie. 14, 44-45 Pecopteridae 14, 76-91 Pecopteris 17, 18 arborescens (Brongniart) Stern- berg 15, 80-81 dentata Brongniart 15, 84-85 miltoni Artis 14, 78-79, 86-87 pennaeformis (Brongniart) Stern- berg 15, 82-83 pseudovestita White 14, 76-77 squamosa Lesquereux 14, 78-79 unita Brongniart 15, 86-87, 88-89 vestita Lesquereux 14, 76-77, 78-79 Port Byron, fossils from 48 Ptychocarpus unita (Brongniart) Weiss 15, 90-91 Ptychopteris spec 15, 17, 108-109 Sigillaria 16 camptotoenia (Wood) Wood. .14, 40-41 Skinner mine, fossil plants from. ... 9 Species, definition of 12-13 Sphenophyllales 14, 16, 30-31 Sphenophyllum 16 emarginatum (Brongniart) Koe- nig 14, 30-31 majus (Bronn) Bronn 14, 30-31 Sphenopteridae 14, 44-47 Sphenopteris 17, 18 capitata White 14, 44-45 chaerophylloides (Brongniart) Presl 14, 46-47 gracilis (Brongniart) Presl 14, 44-45 Spiropteris 18, 74-75 Spring Valley, fossils from vicinity of 9, 10, 52-53 Staphylopteris 18 sagittatus Lesquereux 15, 102-103, 108-109 [NDEX- PAGE Stephanian, correlation of flora from 10 Stephanospermum 18 Stigmaria 16 ficoides (Sternberg) Brongniart. . . 14, 16, 42-43 Syringodendron 16 porteri Lesquereux 14, 40-41 T Trigonocarpum 18 noeggerathi Sternberg 15, 106-107 Continued 113 PAGE Tripterospermum 18 rostratum Brongniart 15, 104-105, 106-107 W Walsh, W. E., specimens given by.. 12 White, David, assistance of 3, 11, 12 Wilmington Star mine, fossil plants from 9 Young, C. D., fossils collected by. .10, 12