TJie Missourian Series of the Carboniferous. — Keyes. 309 
the Nodaway river 25 to 30 miles; and they are also well 
displayed on the Platte river in Missouri, at and north of Sav- 
anah. On the Kansas river between Lawrence and Topeka 
other good sections occur. On the Missouri river above For- 
est City they dip beneath the water-level and for a distance of 
over 50 miles do not again rise. 
Fofbes Limestone. In the Missourian series there is one 
lirnestone of special importance between the Plattsmouth and 
the summit Cottonwood formation. This has been called the 
i^orbes formation from the town of Forbes, in Holt county, 
i\Iissouri, in the vicinity of which excellent exposures occur. 
1 he stratum has been referred to many times in the literature 
of the region, but with no special designation. The fact that 
it forms an important stratigraphical horizon over a large area, 
in four states^ warrants its recognition as one of the guiding 
iD^ds for correlation. Its correlation with the limestones of the 
Kansas river section, in the vicinity of Topeka has not been 
suggested. The thickness of the Forbes is about 25 feet. 
Atchison Sliales. In the most recent papers the name 
Wabaunsee has been used in connection with the formation 
under consideration. The latter name is derived from one of 
the counties in central Kansas where the formation is well ex- 
posed. The designation is that of Prosser for a sequence of 
shales that occupy the interval between the Cottonwood lime- 
stone and the Osage coal. It was subsequently made to in- 
clude a few feet of shale below the last named horizon and to 
extend down to the Forbes limestone. The equivalent of the 
latter in central Kansas may be the Topeka limestone. 
There seems to have been another name that has been used 
in nearly the same sense as Prosser originally used Wabaunsee 
This will probably have to be substituted for his name. As 
early as 1873 Broadhead designated the uppermost beds of the 
Upper Coal Measures as exposed in northwest Missouri, as the 
"Atchison County Group". Subsequently he refers often to 
them. His descriptions of the lithological and faunal charac- 
ters, though widely scattered, are very complete. Regarding 
the stratigraphic position of the formation it reached from the 
summit of the Missouri section — now known to be about 75 
feet below the Cottonwood limestone — almost to the Nodaway 
coal which is nearly on the same horizon with the Osaee coal 
