202 University of Kansas Geological Survey. 
Kansas Niobrara is principally chalk, in some places being perhaps 
more nearly composed of microscopic organisms constituting true 
chalk than elsewhere. But all over the state, wherever the upper 
Niobrara rock occurs, a sufficiently large proportion of such organ- 
isms are found to give the limestone a chalky character. 
During Fort Pierre time the conditions were again reversed as 
regards sediments from the dry land, almost all the Fort Pierre 
formations in Kansas being shales or shaly limestones which must 
have been produced by the accumulation of sediments brought down 
from the land areas. The climatology of Cretaceous time in Kansas 
is an interesting subject, one which might produce valuable results 
were it studied in sufficient detail. 
THE UPPER CRETACEOUS. 
BY W. N. LOGAN. 
In this Report will be given, first, a general discussion of the 
Upper Cretaceous of Kansas, and second, a number of sections 
which will serve to show the principal features of Upper Cretaceous 
Stratigraphy. 
GEOGRAPHY. 
Approximately the upper Cretaceous occupies in north central 
Ikansas an area of twenty five thousand square miles—nearly one 
third of the total area of the state. The main portion of this area 
lies between the 38th and 40th parallels north latitude and the 
97th and 160th degrees 30 minutes west longitude. The border 
lines of the area are very irregular. On all of the principal streams 
which flow through the formation outcrops occur far beyond the 
boundaries of the main area. On the Smoky Hill river they extend 
as far west as the Colorado line. The direction of the longitudinal 
axis of the group is from northeast to southwest. The eastern and 
western general boundary lines of each subdivision are nearly 
parallel. The boundary lines of the Dakota are the most irregular. 
Narrow arms extend almost through the Benton area in many 
places. South of Great Bend a probable northward movement of 
