118 University Geological Survey of Kansas. 
The casing is driven continuously and at the same rate that 
drilling is carried on, thus maintaining the same distance be- 
tween the bit and the bottom of the casing. This is accom- 
plished by a driving block, which is attached to the cable or a 
rod connecting with the line of tools. The weight of the tools 
drives the casing. 
As the wells discussed in this report are under 1500 feet in 
depth many of the difficulties encountered in drilling holes up 
into the thousands of feet are not experienced; then, too, the 
formations met with are with a few possible exceptions easily 
worked with all forms of drilling devices. 
In several localities, especially in the southeastern portion of 
the state, a very hard limestone, commonly called ‘‘ bastard 
rock,’’ is found, but by far the most difficult formation to drill 
is the cherty formation of Galena, which is not only very hard 
but is in most parts fissured. Diamond drills cannot con- 
veniently be employed in such rock, and churn drills are fre- 
quently troubled by the catching of the tools. The calyx drill, 
using both the cutter and chilled shot, together with cement- 
ing, can readily cope with such conditions. 
The self-contained forms of churn drills are largely used for 
the drilling of wells and for prospecting purposes, especially in 
prospecting for oil, gas, and coal. 
Opening Up and Clearing Out Wells—When a well has been 
sunk to the stratum in which water is known or believed to 
occur and nothing is found, or it is obtained in such small 
‘quantities as to be of no special value, it is usual to try opening 
up the bottom of the hole. This is accomplished by firing off a 
charge of explosive, usually nitroglycerin, which has been 
lowered to the desired point. A cavity is then formed or the 
formation is greatly disturbed and fissured, thus producing a 
large area of fissured and broken rock through which the water 
can readily pass to the hole. The same method of procedure is 
often followed with a well which has been yielding a sufficient 
supply but begins to fall off or ceases altogether. 
It is not uncommon, however, to bring about results exactly 
the reverse of what is expected, namely, the entire cutting off 
of the supply. Several cases are on record where very good 
wells have been rendered worthless by such a process of open- 
ing up or clearing out. 
