274 University of Kansas Geological Survey. 
the drainage conditions of the Tertiary formation. By an exami- 
nation of the well records already given it will be seen that almost 
every one of the wells passed through from one to many beds of — 
clay. The Gray county well near the Cimarron found a very plastic 
clay almost entirely free from sand within less than thirty feet of 
the surface, although the well is located in the Sand Hills on the 
south of the Arkansas. This well shows that the sandhills are super- 
ficial in position and do not extend very far under the surface. 
Well No. 3 in Grant county passed through more clay than all other 
materials combined yet it was located on the high uplands between 
the two Cimarron rivers. And so with the other wells. 
An examination of the various natural sections along the banks 
and bluffs of the streams reveals a similar set of conditions. Not 
unfrequently do we find a section from 25 to 100 feet in hight 
which contains little but plastic clay. In other places similar evi- 
dences are obtained from wells drilled by private parties scattered 
here and there over the country. One of the most remarkable cases 
yet observed is that of a well drilled during August 1896 about 
three fourths of a mile south of the little town of Atwater, in 
Meade county. Here a well went to a distance of 288 feet, passing 
through nothing but clay, until almost the total depth was reached. 
Other wells near by found a much less amount of clay. This con- 
dition is frequently met with elsewhere implying that the clay beds 
are lenticular masses, sometimes elongated, and at other times 
circular in form. ‘They are scattered all over and through the 
Tertiary of Kansas, and can not be located from surface indications. 
Such an oblong lenticular mass lies to the north of Garden City 
along the north part of the Arkansas river valley. Here, for a 
distance of four to six miles along the river, is a narrow strip 
lying just back of the river valley proper beneath which the clay 
exists from 75 to 100 feet in thickness. Many attempts have been 
made to obtain water in this particular area by different citizens, 
each of whom has usually abandoned his well because it was known 
that only a short distance either north or south water could be 
found in the sand beds at comparatively shallow depths, while if 
drilling was continued in the clay area a depth of 100 feet or more 
would have to be passed before water could be reached. The clay 
