A NATURALIST IN THE GREAT LAKES REGION 



Pottsville sandstone or con- 

 glomerate (Millstone 

 grit) 



Mississippi period 

 Upper Mississippian 

 (Chester series) 



Grand Rapids series 

 in Michigan 



Marshall series in Michigan 



Lower Mississippian 



(lowan series) 

 Meramce 



St. Genevieve limestone 



St. Louis limestone 



Spergen sandstone 



Warsaw 

 Osage 



Keokuk limestone 



Burlington limestone 



Fern Glenn limestone 

 Kinderhook 



Chautauquan limestone 



Hannibal shale 



Sulphur Springs sandstone 



Louisiana limestone 



second- (Springfield No. 5) and 

 third-vein (LaSalle No. 2) coals, 

 the latter just above the Potts- 

 ville series, including clays and 

 sandstone 



Typically exposed in southern Illi- 

 nois 



Kincaid limestone 

 Degonia sandstone 

 Clare limestone 

 Palestine sandstone 

 Menard limestone 

 Waltersburg sandstone 

 Vienna limestone 

 Tar Springs sandstone 

 Glen Dean limestone 

 Hardensburg sandstone 

 Golconda limestone 

 Cypress sandstone 

 Paint Creek limestone 

 Yankeetown formation 

 Bethel sandstone 

 Renault limestone 

 Aux Vases sandstone 



Names of formations are for the most 

 part the same in the Central West 



