GABBROS OF EAST SOOKE AND ROCKY POINT. 
25 
Deposition from the hornblendizing solutions apparently- 
sealed most of the joint and fault fissures resulting from the 
fifth movement, so that it was not until the sixth movement, 
which produced new joints and small fissures cutting the old, 
that the escape of the aplitizing solution took place. The seventh 
movement resulted in further faulting. No new fault- planes 
were produced, but the stresses were relieved by slip along the 
fault zones of the fifth movement, with consequent brecciation 
of the hornblendite which filled them. The eighth movement 
resulted in further jointing. In addition, some later movements 
probably occurred, as two or three sets of joints cut the aplite 
veins and each other; but as it is difficult to distinguish between 
the different sets, the actual number of movements producing 
them is unknown. 
In spite of the large number of observations of strike and 
dip of the various joint, vein, and dyke systems, no regularity 
could be determined, even among those systems which belong 
rather definitely to a single set. It is possible that a regularity of 
arrangement might be established by a more intensive study, 
which might show that much of the jointing has been due to com- 
pressional forces ; on the other hand, it is probable that many of 
them are tension joints, formed by the strains set up during the 
cooling of the mass, and without regularity of arrangement. 
A somewhat greater regularity is found in the faults. Their 
strikes vary considerably, but in general fall into two sets, the 
one Isetween north 10 degrees west and north 20 degrees east, the 
other between north 45 degrees east and north 65 degrees east. 
In most places the fault planes have a steep or vertical dip. 
The displacement in all the faults noted is nearly horizontal, 
as shown by the direction of the striae on slickensided surfaces. 
The dip of the striae was not observed to exceed 20 degrees, and 
was invariably to the southwest. The amount of the displace- 
ment is difficult to estimate, as good horizon markers are lacking, 
but it is probably not much over 1,000 feet even in the largest. 
