LOGAN. | The Upper Oretaceous. Pal 
XXVIII shows this, and Plate X XLX shows the same chert capping 
a chalk bluff at the old mill, Norton. 
Some exceilent mineral pigments have been taken from the chalk 
beds near Wa-IXeeney to be used in the manufacture of paints. 
Erosion has produced many peculiar forms in the Smoky Hill 
chalix beds. Near Hackberry creek, in Gove county, is a mound 
of chalk 70 feet in hight, known as Castle Rock, and shown in 
Plate Vif. It stands on an open terrace a few rods from the bluffs. 
In form it resembles an ancient castle, hence the name. Near 
Elkader is a group of these chalk forms which because of their 
pyramidal shapes, are calledthe Pyramids; seePlateXXXV. ‘Castle 
City” is the name of a group which is situated near the western line 
of Gove county. The highest of these chalk mounds is nearly sixty 
five feet. Hrosion within the chalk area is rapid and large quantities 
of chalk are carried away by each freshet. 
The chalk beds of Kansas are particularly rich in fossil remains, 
a Synoptical review of which by Doctor Williston follows this paper. 
THE FORT PIERRE.1 
Resting upon the Pteranodon beds in northwestern Kansas is a 
bed of shales which belong to the Fort Pierre group of the Montana 
Oretaceous. Outcrops of these shales occur on the Beaver in Raw- 
lins county, the Prairie Dog, in Norton, and on the Hackberry, Re- 
publican and Arickaree in Cheyenne county. The upper shales are 
dark blue in color, argillaceous, chafiy and loosely textured. The 
next band is variegated in color, but usually of a rusty yellow. 
These shales contain nodules of a flat, dise-like shape. The freshly 
fractured surface of these nodules presents a bluish gray color, but 
the outside is like the shales, of a yellowish color. These nodules 
sometimes contain invertebrate fossils. 
The maximum thickness of the Fort Pierre shales in Kansas does 
not exceed 200 feet. ‘The principal invertebrate fossils of the Fort 
Pierre group are Avicula fibrosa, Inoceramus cripsii,and Lucina occi- 
1 In his paper, “On the Stratigraphy of the Platte Series’? Colorado College 
Studies, 1896, Prof. F. W. Cragin classes the Arickaree shales as Fox Hill. They 
were first called Fort Pierre by Prof. Robert Hay in his paper on: ‘‘Water Resources 
of a Portion of the Great Plains,’’ published in the Sixteenth Annual Report of the 
Director of the U. S. Geological Survey. 
2Mr. T. W. Stanton, of the U. S. Geological Survey, kindly determined these 
species for the University in the Autumn of 1896. 
