
bei | 

240 STRUCTURAL AND FIELD GEOLOGY 
we may infer that many fissures may never have reached the surface at 
the time of their infilling, the outcrops we now see having been exposed 
by denudation. 
Simple and Complex Lodes.—A lode is said to be szmple 
when it occupies one single well-defined fissure (see Fig. 87). 
Often enough, however, the 
formation of a fissure has 

AWE 
2, Z. been accompanied by much 
Z2iBE 1 ‘ 
AAA rock-shattering, the adja- 
eZ yy ASE cent rocks being confusedly 
Z Vz Z jumbled and crossed in 
734 SYA every direction by nume- 
/ EEE rous branching cracks and 
é Zs 3 
[ZEEE crevices. When all these 
LE cavities .are filled iain 
; ZZ mineral matter we have a 
i eee complex lode (see Fig. 88). 
Ste <a, One and the same lode 
Fic. 88.—CoMPLEX LopE. (After may be simple in one part 
R. Beck.) of its course and complex 
in another, This asic 
infrequently the case when a lode traverses rocks of very 
different kinds. For example, a vein may be simple while 
passing through rocks which have yielded readily to tension, 
but becomes complex when an 
it begins to traverse some 
massive irregularly jointed 
rock (see Fig. 89). 
Transverse and Coin- 
cident Lodes.—Lodes cut- 
ting through stratified rocks 
usually cross the planes of 
bedding at an angle, and 
are then said to be ¢rans- 
ets (see Fig. 90). oe FIG. 89.—LODE DIVIDING AND BRANCHING 
and again, however, especi- IN IGNEOUS ROCK. (Plan.) 
ally when the strata dip at 
a high angle, a lode may coincide with the planes of bedding. 
The epigenetic character, however, is usually apparent, the 
lode not being strictly confined between two bedding-planes, 

