220 University of Kansas Geological Survey. 
appears, but reappears as a capping for the Blue Hills in Russell, 
Mitchell and Republic counties. Its total thickness is 50 or 60 feet. 
A single escarpment on the Hackberry measures 45 feet. It rests 
upon the Septara and upper shale bed of the Benton. The Fort Hays 
limestone is used to a limited extent for building purposes. When 
taken from the quarry it is very soft, therefore, easily cut, or sawed 
into any desired form. Under exposure it hardens somewhat, but 
is considered too soft to be very valuable as a building stone. 
The Ptleranodon Beds.—The Pteranodon beds, or Smoky Hill 
chalk, rests upon the Fort Hays limestone. ‘These beds represent a 
total thickness of more than 300 feet. They vary in color from a 
light blue, through lavender, yellow and buff, to light red. Under 
fresh exposure the chalk, in many instances, presents the appear- 
ance of a blue shale, and sometimes has been taken as such by 
persons doing geological work in western Kansas. ‘These freshly 
exposed beds, however, under the weathering influnces of air and 
water, soon change their shale-like appearance and their blue color 
to red, yellow or buff, due probably to a change in the character of 
the iron compounds in it. In an exposure of chalk northeast of 
Lebanon, in Smith county, the chalk had a laminated appearance, 
and was blue in color in all parts except along the borders of five 
vertical fractures where it was the ordinary buff. The action of the 
surface water, as it passed along these crevices, probably accornts 
for the bleached appearance of the chalk along the border of the 
fractures. In passing up the Smoky Hill river to the state line the 
exposures near the river bed are found to be blue in color, while 
those back on the bluifs are variegated. Wells which pierce te 
Tertiary deposit, lying immediately above the Pteranodon beds, 
usually strike blue chalk. That they do not always do so is easily 
explained when we remember that there was a period of erosion 
preceding the deposition of the Tertiary formation, which may have 
resulted in the bleaching out of much of the chalk. 
In a few places the chalk beds carry large amounts of chert which 
seem to be interstratified with the chalk. This is well represented 
at Norton, along the Prairie Dog creek. Northwest of the town 
about a mile the chert is quarried to a considerable extent. Plate 
