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 



