380 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
sediments as a rule, leaving it only to cut across abruptly from one 
stratum-plane to another. This irregularity is never so extensive as 
in the case of many veins filling ordinary fissures; and often the 
structure of a region can be deciphered by the inclination of the 
shaft-heads. In position, they sometimes lie between strata of 
slate, still more often on the contact between slate and sandstone 
or quartzite, and very seldom between beds of sandy material. It 
is common for ajiumber of veins to lie parallel, separated by a few 
inches of country-rock; and these can generally be proved to have 
connection with each other. Both Moose River and Waverly 
show this. In the latter village the “ barrel lead 7 east of the lakes 
is composed in places of parallel sheets of quartz, separated inter¬ 
mittently by thin laminae of slate, the whole forming one large 
vein. In very many places stringers, locally called “ angulars,” run 
out from the main veins into the country-rock above and below; 
and it is claimed by miners that they are most abundant in the 
hanging-wall of a “roll,'’ and indicate the proximity of a pocket of 
gold. 
The composition of the vein filling is uniform. By far the larger 
part of the gangue is quartz, which in many places is the only 
mineral; but often calcite is plentiful, erratically distributed. There 
is no definite order of growth, and frequently the quartz and cal¬ 
cite are indiscriminately mingled; yet in some cases quartz lines 
the walls, and calcite fills the interior. The former is usually com- 
pact, but seldom of the density and whiteness seen in many of the 
north-south barren fissure-veins. In places it has a cellular struc¬ 
ture, showing successions of growth in the crystals; rarely drusy 
cavities are seen in the center of the veins, with free crystal termi¬ 
nations projecting into them. Frequently the quartz has been 
given a somewhat mealy appearance by the crushing which it has 
endured. Indeed, in its generally shattered and fragmentary state, 
most noticeable in thin veins, but observable often in thick ones, it 
bears witness to the action of powerful orogenic forces. The most 
complete shattering of the rocks, accompanied by small dislocations, 
usually is found where the folds plunge east and west; and for 
the most part the bedded veins have not taken advantage of the 
conditions. Much secondary growth has taken place, later addi¬ 
tions of quartz, in some instances, increasing the thickness of the 
veins several fold. This is especially true in “ rolls,” to be described 
later, where the largest amount of accretion is to be observed. In 
