206 University of Kansas Geological Survey. 
distance between the two points is one hundred ninety miles. Thus 
the dip is a little more than six feet to the mile for the upper 
surface of the Dakota in this direction. The Septaria horizon is 
found near Laird, in Ness county, at a height of 23800 feet. At 
Tipton, in Mitchell county, the same horizon occurs at an elevation 
of 1800 feet. Tipton is one hundred miles northeast of Laird and 
the difference in elevation is 500 feet, consequently the dip for the 
Fort Benton upper beds is five feet per mile. 
These comparisons of elevation are sufficient to show that the dip 
of the Cretaceous beds does not exceed seven feet to the mile in 
any part of the state when measured over long distances. In 
different places, however, locally a much greater dip is found. 
DIVISIONS.* 
Three principal divisions of the upper Cretaceous are repre- 
sented in Kaisas. These divisions are: the Dakota, not divided; the 
Colorado, divided into two groups, namely, Benton and Niobrara; 
and the Montana, represented by a single group, the Fort Pierre. 
The vertical position of these divisions is shown by the accompany- 
ing vertical section, Plate XX VII. Beginning with the Permian, 
upon which the Cretaceous beds rest, the order of stratigraphic 
sequence is as follows: first Dakota, second Benton, third Niobrara, 
fourth, Fort Pierre. These groups will now be considered in the 
order in which they have been named and a few facts in regard to 
the geography, stratigraphy, economy and paleontology of each 
will be given. 
THE DAKOTA. 
The Dakota occupies a narrow belt along the eastern border 
of the Cretaceous area. It extends from Washington county on 
the northeast to Ford county on the southwest in one continuous 
area, and has a number of small outlying areas farther to the south- 
west, aS already mentioned. Its greatest width is a line extending 
from the confluence of Big creek and the Smoky Hill river to the 
western line of Morris county. The narrowest portion of the belt 
i pier a discussion of the divisions of the Cretaceous see introduction to this 
article. 
