THE SCOPE OF ECONOMIC GEOLOGY 11 
saddles.” Adjacent lodes may dip in opposite directions 
like the two limbs of a saddle-lode that has lost its cap; 
and if the two lodes were the flaps of a saddle other saddle- 
lodes would be expected below. False-saddles may be due 
to the occurrence of a bedded vein near a rake vein ; either 
of them may be the main lode and the other the branch. 
The search for an underground repetition of this structure 
should be made along the major lode, and not along the plane 
Pisecting the angle between the two lodes (Fig. 6). 
Lodes sometimes bifurcate into approximately equal 
divisions, but they more often give off branches or spurs 
{cf. Figs. I, 6). The branches may be small and are then 
known as ** stringers.” Those on the hanging-wall of a lode 
are often described ag © leaders '* or * feeders,” on the view 
that they fed the lode; those on the footwall are called 
* droppers.” 
In some fields that have been broken by intersecting 
fractures the quartz-veins form an irregular network; 
the veins may divide and reunite, or disappear irregularly. 
Lodes are often formed along fissures, as they are channels 
for the passage of metalliferous solutions. As the solutions 
cool they deposit some of their constituents on the walls of 
the fissure; crystals thus formed are often prismatic, and 
they grow crowded and parallel like the teeth of a comb; 
each sheet with this * comb structure” is known as a crust. 
The successive crusts may be of different materials, and 
may fill the fissure or leave only a thin median space known 
as the vugg. Crustified lodes are formed by the gradual 
infilling of a fissure from solutions. The fissure may be 
tnlarged by repeated earth-movements, and thus a thick 
lode may be formed of numerous crusts. They may be 
Symmetrical on the two sides, but, especially in the case of 
moderately inclined lodes, the one side may be thicker, and 
have more crusts than the other. The Three Princes Lode 
at Freiburg in Saxony at one part consisted of twenty crusts, 
which in order from the outside were blende, quartz, fluor, 
blende, barite, pyrites, barite, fluor, pyrites, and calcite, 
with a central vugg. This sequence indicated repeated 
variations in the temperature and composition of the solu- 
tions which deposited the lode, 
A lode is not always sharply marked off from the country,