659 
greater or less distance. The width of a vein is far 
from uniform ; frequently opening from a foot or two 
wide to as many yards, and then contracting to a 
mere joint. The width varies also with change of strata; 
it is much greater in the hard strata than in the soft ; 
it is, generally, more open in limestone than gritstone, 
and much contracted in the plate or shale. Frequently 
the vein is found four or five feet wide in the limestone 
and gritstone, when it is scarcely perceptible in the plate. 
Where the longitudinal extremities of a vein have been 
explored (which is very seldom done), the lode is found to 
split into numerous branches, which quickly terminate. 
This ramification of the lode is often anticipated, from the 
introduction into the "bearing" beds of accidental shales. 
Rake veins are generally fault veins. As a rule, the 
strata are lower on that side to which a vein hades or 
inclines, called the " hanging wall," than on the one upon 
which it rests, known as the "foot wall." 
The extent of throw varies from a few inches to twenty 
or thirty fathoms ; this extreme throw being often met with 
when veins are in the immediate vicinity of each other. 
The "strength" of a vein is considered to be in direct 
proportion to the extent of fault or throw ; but a vein with a 
difference of from six to eighteen feet is regarded with more 
favour by the miner, than one with a greater or less throw : 
such a fault being indicative of sufficient strength of vein 
to ensure its continuity at a moderate size, but not such as to 
destroy the effect supposed to be produced by certain beds 
when in the same horizontal line on each side of the vein. 
When rocks, differing in their character and composition, 
form the opposing sides or cheeks of the vein, we do not 
often expect to find a deposit of lead ore. There are, 
however, exceptions to this rule. At the Grassington 
mines, in Wharfedale, are two veins, each throwing the 
D d d 2 
