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- 



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