396 . ILLINOIS STATE ACADEMY OF SCIENCE 



FOSSIL FLORA OF BRAID WOOD, ILLINOIS 



A. C. NoE, University of Chicago 



Braidwood is situated fifty-nine miles southeast of Chi- 

 cago on the Chicago and Alton Railroad. Two miles 

 northeast of the Chicago and Alton Station is located a 

 medium sized coal mine which was still working before 

 the beginning of the strike, and which it is to be hoped 

 will continue to be active for a long time to come after the 

 strike is settled. It is the last coal mine in Mining Dis- 

 trict No. 1 (Longwall) which contains large numbers of 

 excellent plant impressions. The owners, the Skinner 

 brothers, are very friendly toward collectors, and the 

 active member of the firm, Mr. David Skinner, together 

 with his mine manager, Mr. William Oswald, cordially 

 welcome and generously treat all serious-minded collec- 

 tors of fossil plants who visit their mine. They receive 

 every year several times, large and small geology classes 

 from the University of Chicago, and give- them every 

 facility for studying their mine and their fossils. The 

 author takes great pleasure in acknowledging his indebt- 

 edness to these two men. 



The log of Skinner mine No. 2, the mine in question, is 

 lost, but the log of the Maltbj' mine, located in the next 

 section east, and abandoned in 1887, is still at hand. Ac- 

 cording to it, the workable coal seam begins at a depth 

 of 48 ft., 4 in. This seam is 40 inches thick, with 20 inches 

 of fire clay below it. Under this fire clay lies another coal 

 seam 9 inches in thickness, and under it are 18 in. of fire 

 clay. Above the workable coal seam is a layer of shale 

 of a thickness of 25 ft., 4 in., above which follow 8 ft. 

 of sandstone, 8 ft. of blue clay, 6 ft. of gravel, and 1 ft. 

 of soil. The fossil plants occur in a zone of about 6 ft. 

 in the shale, beginning immediately above the workable 

 coal seam. They are most numerous next to the coal. 

 The fossils appear in either calcareous concretions em- 

 bedded in the shale, or as impressions directly in the 

 shale. 



The shale of Braidwood consists of various species of 

 Calamites, Annularia, especially A. Sphenophylloides, 



