116 University Geological Survey of Kansas. 
and, second, it will not drill past crevices unless the crevice can 
be cemented, which in itself is expensive and delays the work. 
Again, some crevices are too large to cement, while others 
have streams running through them, thus precluding the idea 
of cementing. 
It is then evident that both the cutter and chilled-shot meth- 
ods are limited, but one will usually work where the other will 
not as arule. To illustrate, say that a very hard stratum of 
rock is struck while drilling with the cutter, the chilled-shot 
process can be substituted; again, if a crevice is met, change 
back to the cutter, which, although it may work slower, may 
be employed to cut past the objectionable point, cutting a new 
groove for the shot process again, or cementing may be re- 
sorted to. 
The chilled-shot process consists in using a blank bit; that 
is, one without teeth, but having a smooth or annular edge. 
This blank bit fits into the groove formed by the toothed bit or 
cutter. On the sides of the bit are grooves reaching to the 
lower edge. Through these grooves the chilled shot is fed to 
the bottom of the hole, and as it wears out and is lost, the sup- 
ply can be maintained. Pressure is given by the weight of the 
drill-rod above, which, combined with turning, rubs the shot 
into the rock and thus cut and scour it out, the wash water 
bearing away the loosened material. 
Casing Drill-holes.—Casing consists of placing a wooden or 
iron lining in the hole in order to maintain its sides. Wood 
is not used for lining deep-bore holes. Iron or steel are the 
only suitable materials, and at the same time are fairly inex- 
pensive. Casing is, as a rule, necessary as drilling proceeds, 
unless the hole is of moderate depth and the formations pierced 
are solid and will maintain their position until the hole is com- 
pleted. 
In the churn-drill process, there is, in some respects, greater 
necessity of casing the hole as soon as drilled; that is, keeping 
the casing a short distance above the bottom, because of the 
lashing and rubbing of the rope and line of tools against the 
sides, which causes them to crumble and cave in. The wash 
