MIDDLE DEVONIAN COAL IN ILLINOIS 21 



and deposited in a shallow, nearshore environment suitable for the growth of ma- 

 rine organisms. Deposition near shore is also indicated by the quartz grains in 

 the coal, and especially in the limestone, which contains the coal. 



Only a small amount of plant debris was disseminated in the overlying and 

 underlying silty to sandy lime mud. Thus, the coal and coaly shale represent a 

 short episode in the geologic history of the Middle Devonian of central Illinois. 

 It provides evidence, however, that a rather diversified flora existed near the beach 

 in a period that was characterized by limestone deposition. 



