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268 University of Kansas Geological Survey. 
so firmly cemented with silica that a rock similar to quartzite has 
been produced. On the uplands north of Stockton likewise a 
silicious cement has been deposited between the grains of sand pro- 
ducing a rock which is quite like quartzite. Near the Saint Jacob’s 
well in western Clark county silicious cement has been deposited 
between the grains of sand, forming a close-grained rock. 
But throughout the Tertiary area of the state, with these few 
exceptions, wherever the sand and gravel are held together by any 
kind of cement it seems to be calcium carbonate. The firm mortar 
beds near Dodge City and elsewhere crumble to grains of sand and 
gravel when acted upon by an acid which will dissolve the calcium 
carbonate. 
The degree to which this cementation is carried is astonishingly 
great. In an examination of materials from the different state wells 
as already referred to it was found that with scarcely an exception 
the whole of the materials taken from them and at a distance more 
than 5 or 4 feet below the surface retained enough carbonate to 
effervesce strongly when placed in acid. Every pinch of clay or 
loose sand, with the exception of the sand which is water-bearing, 
would effervesce vigorously. 
The amount of cement is exceedingly variable, even in the same 
kind of material. There are horizons in most parts of the state at 
which the clay and silt are heavily charged with calcium carbonate. 
Sometimes this will be a thin layer not exceeding 12 to 20 inches in 
thickness. Other times it will be a mass 20 to 40 feet in thickness. 
Occasionally a layer of such fine calcium carbonate is near the sur- 
face and plowed fields frequently have a light color as a result which 
in the distance looks almost like snow. 
The arrangement of the cement in the mortar beds is more regular 
than elsewhere, but not infrequently here even it is quite irregular. 
It almost always shows an approach to concretionary forms. In 
different places along an exposure of the mortar beds a careful ex- 
amination will show that the first deposition of the cement was in 
the form of granular masses. A later deposit cemented these to- 
gether into larger masses or concretions and in many instances a 
third or fourth period of deposition is plainly marked so that the 
larger fragments previously formed are included in one concretion 
