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Lesquereux's nomenclature is obsolete and needs frequent corrections 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 



