66 STEPHEN TABER 
Fig. 5), but in such cases the pyrite was deposited subsequent to 
the deposition of most of the calcite, and well-formed cubes and 
pyritohedrons may be found replacing impartially vein calcite and 
wall rock. Small seams of pyrite in places cut directly across the 
veins. 
Fey C ED, 
Scale 
0 Ye. Inch 
ee 
Fic. 2.—Calcite veins in limestone. Coarsely crystalline calcite (C) and fibrous 
calcite (F). 
ORIGIN OF THE NON-FIBROUS VEINS 
The facts cited above preclude the theory that these veins are 
due to recrystallization of country rock in situ or that they could 
have been formed through replacement; and the presence of de- 
tached inclusions of wall rock argues against the hypothesis that 
the veins were deposited in open fissures. If the veins were formed 
as a result of fissure filling, deposition of vein matter must have 
begun on the walls and continued inward until the opposite sides 
