298 The American Geologist. November, \s'dT> 
of each stratum beyond that which is under it. The basal 
sandstone was formed partly from the residual material left 
on the surface of the Ozark series when subjected to atmos- 
pheric action, and partly from material (mostly lime in solu- 
tion) brought down by the streams from the land on the north 
and east. Animal life of forms easily preserved was nearly 
absent. This constitutes the first epoch. 
A deepening and broadening of the basin instituted the 
second epoch, which was characterized by its abundance of 
animal life and especially by the prodigious quantities of 
crinoids and kindred forms which lived and died and gave 
their debris to make the dejiosits of this epoch. The basin 
evidently had free communication with the open sea, and its 
waters were salt. The streams also which emptied into the 
sea near this locality must have been remarkably free from 
sediment of any kind; during the long period required for the 
accumulation of three feet of crinoid debris, wholly of small 
species, the amount of sediment brought from the land was 
very little. 
The third epoch was characterized by a still broader but 
slightly shallower basin, less animal life, or at least more 
rapid deposition of sediment brought by the rivers from the 
land, which was deposited as a ealcareo-argillaceous mud to 
harden into shaly and "amorphovis'" limestones. 
In the fourth epoch the basin was still more extensive but 
yet very shallow, and fine clay sediment was being rapidly 
deposited, excluding the majority of the animal species which 
had previously inhabited the basin. The deposits of this last 
epoch, making up the Eureka shale formation, vary from a 
few inches to 35 feet in thickness ; but I believe that they do 
not indicate any great length for the epoch. 
With the earth movements w^hich inaugurated the Lower 
Carboniferous age, this region was greatly depressed and the 
surrounding land surfaces were submerged. Hence the base 
of the Kinderhook strata, although conformable to the Eureka 
shale, overlaps it to a vast distance. 
The correlation of the several members of the Devonian in 
this region with the divisions of the system recognized in 
other states is impossible until the paleontologic contents of 
these strata have been thoroughly studied and compared with 
