EARLY PENNSYLVANIA FLORA FROM WEST-CENTRAL ILLINOIS 



stratigraphy is found in Harvey 

 (196*0, Reinertsen (196*0, and 

 Leary (l9T^a). 



The Warsaw Shale of Missis- 

 sippian age is the oldest forma- 

 tion observed in the report area. 

 It is exposed in a small creek 

 southeast of the collecting local- 

 ities, several hundred meters 

 southwest of the point where the 

 creek enters the La Moine River. 

 The Warsaw consists primarily of 

 light gray, bluish gray, or green- 

 ish gray calcareous or dolomitic 

 shale. In some places it contains 

 one or more beds of light gray 

 earthy limestone that are massive, 

 lacking obvious bedding planes, 

 and that scale off in thin blocks 

 upon exposure. Thin beds of dolo- 

 stone, siltstone, and sandstone 

 are interbedded with the shale. 

 Contact with the overlying Salem 

 Limestone is gradational. 



The Salem Limestone is exposed 

 in the area of the collecting lo- 

 calities, forming part of the 



POPE CREEK COAL 



BABYLON SS. 



Covered interval 



Plant 

 fossils 



d»W^^/ V ^ ^^ ^^* Wy N^ t ^^^rf 



WSA ^WA^V W^^V ^^A^V 



z3^^Wi 



^ST LOUIS LS. 



SALEM LS. 



WARSAW SH. 



10 



m U 



Text fig. 3 - Stratigraphic column of 

 the rocks in the vicinity of the 

 Spencer Farm locality. 



sides of the ravine in which the fossil-bearing Pennsylvanian sediments 

 accumulated. The Salem Formation is predominantly a brown to light 

 brownish gray limestone or dolostone. The limestone is dense to argil- 

 laceous, silty or even sandy, and commonly occurs in irregular thin beds, 

 This limestone or dolostone may give way to a light gray or greenish 

 gray dolomitic siltstone or sandstone, or a light greenish gray calcare- 

 ous or dolomitic sandy shale that closely resembles the Warsaw. The 

 Salem is 10 to ik meters thick. 



The youngest Mississippi an formation in the report area is the 

 St. Louis Limestone. Only part of the formation is present, pre-Penn- 

 sylvanian erosion having removed at least the upper portion, and in most 

 areas, all of the formation. The St. Louis is a light gray, dense to 

 lithographic limestone containing small amounts of white to light gray 

 chert. Thin beds of light greenish gray shale are interbedded with the 

 limestone. The limestone commonly is brecciated, consisting of angular 

 fragments of light gray, dense limestone in a matrix that is darker gray 

 and weathers rusty brown. The maximum thickness of the St. Louis ob- 

 served in the immediate area is h meters. 



The fossil-bearing strata are the lowermost Pennsylvanian depos- 

 its in the area and belong to the Caseyville Formation. They consist of 

 very irregularly interbedded siltstone, fine-grained sandstones, and 

 shales deposited in steep-sided depressions within the Mississippi an 

 limestones, primarily the Salem Limestone. The siltstones are gray and 

 well sorted; however, lenses of coarse quartz sand grains in a matrix of 



