114 University Geological Survey of Kansas. 
an action which has been likened to that of a mallet and chisel 
in a stone-cutter’s hands. 
Water is forced down the rod, as in the diamond drill, through 
the core-barrel and out between the teeth of the bit or cutter, 
thence to the surface. The speed of the raising currents will 
vary with the area of the more or less constricted passage exist- 
ing between the hole and the drill parts. That part of the dis- 
tance in which the velocity of the rising currents is greatest is 
from the bottom of the hole to the top of the calyx tube—the 
space being small, beyond this upper point the cross-sectional 
area becomes suddenly enlarged, thus causing a decidedly rapid 
decrease in the velocity of the currents. The carrying power of 
the raising currents decreasing with the velocity causes a back- 
ward movement or settlement of the materials in suspension, 
which, being unable to settle against the strong raising currents, 
are caught in the calyx tube, and that, too, in the order that 
they occupied in their original position in the strata. Two rec- 
ords are thus obtained—the core and the cuttings or ‘‘chip 
record.”’ 
By means of the calyx the hole is kept clear of sludge, the 
importance of which cannot be too strongly emphasized, not 
only from the standpoint of free and easy drilling, but also to 
prevent the ‘‘jamming in”’ of the drili by sludge. The core is 
removed, sections of rod added and water fed to the rod ina 
similar manner as is employed in the diamond drill. (Plate XI.) 
The speed of the tooth cutter is remarkable in the majority of 
rocks—many shales and sandstones being cut at the rate of 
three-fourths inch per revolution. With very hard rock, how- 
ever, it may be more economieal to employ a diamond bit, and, 
when it is possible, that is, when the size of the hole will allow, 
such a bit may take the place of the cutter. With the larger 
sizes this interehange of bits is impossible, or rather impracti- 
cable, due to the excessive cost of the diamond bit. It is, there- 
fore, customary to use chilled shot, by the use of which very 
hard rock can be cut with comparative ease, and that, too, at a 
low cost. There are, however, some limitations to the chilled- 
shot process; first, it will not work well in soft, pasty rook ; 
