BROADHEAD — COAL MEASURES IN MISSOURI. 



323 



Section on Missouri River (continued). 



In the above Section there are 433' of limestone, 55' of 

 calcareous shale, 730' of argillaceous shale, 289' of sandy 

 shale, 465' of sandstone, 24' bituminous coal, 38' bituminous 

 shale, \\' fire clay, 4L' calcareous sandrock, and 8" iron- 

 stone. 



For convenience and comparison I have separated the 

 coal series into several Groups, each possessing characters 

 somewhat peculiar, and separable from each other by mode- 

 rately well marked natural lines ; but there can scarcely be 

 said to be any strongly marked Groups, and but few strata 

 can be recognized, except by their connection and relation 

 with other beds of the series. 



The base of Group "F" is a good natural line of division, 

 for no beds of fire clay have been found above it, while the 

 workable beds of coal are thicker and more abundant below. 



The base of the Lexington Coal Group is another good 

 line of demarcation, since the coal is mostly below, and the 

 lower limestones differ essentially from those above. 



The Plattsburgh Group is the only well marked group in 

 the whole coal series ; and by its fossils may readily be 

 distinguished from all other groups. 



The following table shows the thickness and general 

 character of the several groups. 



