Dtvonian, Series in South vexf em Jfissoiiri. — Jfers-Jtr/t. 299 
the faunas of other regions. This paper has been prepared 
principally for the purpose of drawing attention to the exist- 
ence of these strata in the southwestern corner of Missouri, 
and to perhaps induce some competent paleontologist to un- 
■dertake the task of deciphering the history and meaning of 
their contents. Since the beds here described occur in a some- 
what isolated basin and were separated from the deposits in 
central Iowa by an extensive land surface, which in Devonian 
time had perhaps a thousand miles of shore line between the 
two basins, it would be of interest to know what difference, if 
any, existed between the faunas of the two regions, and what 
effect the probable inflow of large (juantities of fresh water to 
this more southern basin had on its contained life. 
Although at present unable to correlate the formations on 
paleontologic grounds, I wish to make a few suggestions as to 
what correlations are indicated by the lithologic and strati- 
graphic relations of the deposits. The uppermost horizon of 
Devonian age in the Mississippi valley is almost invariably a 
shale, either black or green. In central Iowa it is known as 
the Hackberrj'- shale; in southern Illinois it is designated as 
the Green shale ; and it is described as occurring in the form 
of a black shale of verj" variable thickness through the Ozark 
liills in Arkansas, westward to and beyond Eureka Springs, 
where it is correlated with the Eureka shale of southwestern 
Missouri. I think it very probable that the correlation of the 
Eureka shale with the Green shale of southern Illinois will be 
found to be correct; but its relations to the Hackberry shale 
of Iowa ai*e not so certain. 
Lithologically the shaly limestone under the Eureka shale 
is similar to portions of the ("edar Valley limestone of Iowa. 
Moreover, it has been subjected at one ])lace in Stone county 
to the peculiar brecciation and contortion which are so char- 
acteristic of the Cedar Valley limestone. This peculiar kind 
of primary deformation of strata is not common to other for- 
mations in the upper Mississippi valley, and it may have been 
confined chiefly to a given period or epoch of geologic time. 
In sliort. I feel reasonably certain that the shal}' limestone of 
my section will be found to be the equivalent of the Cedar 
Vallev limestone of central Iowa. 
