USE OF TERM AUGUSTA 59 



in question. One of the chief reasons for proposing Osage 

 was that the beds of southwestern Missouri were thought to 

 contain a mingling of faunas of both Burlington and Keokuk 

 beds. Insofar as personal observation goes, the Kinderhook, 

 Burlington and Keokuk beds are as sharj)ly contrasted litho- 

 logically, faunally and stratigraphically as in southeastern Iowa. 



From the foregoing it would seem that the '"Osage" forma- 

 tion at its typical locality is practically coextensive, and there- 

 fore synonymous, with the Burlington limestone. Southeastern 

 Iowa has long been regarded as the typical locality of the 

 rocks under consideration. There these beds have been de- 

 scribed more in detail and are better understood than in any 

 other region in which they occur. Since the Burlington and 

 Keokuk limestones manifestly form a single epoch in the geo- 

 logical history of the region, as has been conclusively shown 

 a number of times recently; since a term applicable to these 

 rocks as a whole is desirable ; and since the name "Osage" is 

 apparently unavailable, it has appeared best to adopt for the 

 title of this formation the name of some locality in southeast- 

 ern Iowa where the rocks are well exposed. Along the Skunk 

 river, in the vicinity of Augusta, about JO miles southwest of 

 Burlington, there is exposed the entire succession of these 

 rocks, from the Kinderhook shales to the "geode bed." This 

 name, therefore, seems more appropriate to use than perhaps 

 some other better known term. Good exposures of the for- 

 mation are found all along the Mississippi river from Keokuk 

 to Burlington, as already mentioned. The limestone often 

 stands out in overhanging cliffs over the softer Kinderhook 

 beds, as is well shown in the vicinity of Burlington and else- 

 where. 



The term Augusta, for the formations under consideration, 

 has already been used and adopted in Iowa, and its application 

 in Missouri is equally appropriate. 



Owen's encrinital limestone embraces, practically, the same 

 beds that were afterward called the Burlington; and his lower 

 Archimedes corresponds to Hall's Keokuk group below the 

 geode bed. Shumard seems to have used the term " encrinital 



