Chap. XXVI.] ore-bodies in lithomarge. 
561 
the boundaries of the rock in which they are situated. Let us suppose 
that workable ores continue to a depth of 300 feet as indicated and that 
they are scattered through soft lithomargic rocks. The original outcrop 
is shown at 0. The ore-body of which this is part has been worked by 
0 
Fig. 34. — Scattered ore- bodies in lithomarge. 
means of a large quarry, and found to terminate at a depth of about 100 
feet. In quarrying this large mass, however, several small concretions 
and pockets of ore have been found scattered through the surrounding 
soft Uthomarges. Now it is obvious that if the quarry be abandoned 
with the idea that the ore has come to an end a great mistake will be 
made, several times as much ore as that extracted being left in the 
ground. The obvious point is that the subsidiary concretions and 
pockets should be taken as a warning, and the surrounding rock 
explored. Mr. T. Caplen tells me that at Kodur he has found putting 
down small bore-holes with a percussion drill a very successful method 
of proving the existence of scattered bodies of ore. Timnels driven 
horizontally from the sides of such a quarry would also be of great 
value, as illustrated by B, C, and D, in the figure, two of them striking 
ore and one missing it. Having proved the existence of these scat- 
tered ore-bodies to a depth of 300 feet, it is a very difficult question to 
settle how to win this ore, considering the softness of the rocks in 
which it lies. It is obvious that to make sure of missing no body of any 
size it would be necessary either to remove the whole of the rock from 
