Louderback, G. D. "Benitoite, Its Paragenesis and Mode of Occurrence." University of California Publications.
Page 337
The outcrop occurs on a hill which, as shown in plate 28, is separated from the neighboring ridge by erosional depressions on all sides. Practically all of the country in view in this photograph, which was taken looking a little east of north, is serpentine, including the basal portion of the mine hill. The rock mass directly associated with the veins lies along the top of the hill from a point directly below A to one directly below B, and is about 520 feet long, and perhaps 400 feet in its widest part.

The outcrop of the mineralized belt lies entirely on the side of the summit visible in the photograph and extends along a line determined in the photograph by the right end of the cut and top of the dump. It is a zone of veination which consists of a large number of irregular stringer-veins running along together in the general direction of elongation of the zone, and connected by many branches and anastomosing laterals. The rock in the vicinity of the veins is altered by recrystallization, metasomatosis, and impregnation, in some places porous from solution of certain constituents, in others tough and cemented by natrolite impregnation.

EFFECTS OF EARTH MOVEMENT AND PRESSURE.

Considerable movement has taken place both before and since the mineral deposition, and it is distinctly concentrated along the mineralized zone. The great majority of the planes of movement and crushing lie in or near the plane of strike of the zone of mineralization, but a few are transverse. The effects of pressure may be tabulated:

Genetically related to deposit. 1. Local schistosity.
2. Cracks and spaces giving loci of veins and druses.
Subsequent to deposit. 3. Sheeting, crushing, and brecciation.
4. Faulting and displacement of veins.

In the first three of these groups the planes lie approximately in the zone of mineralization. A few of the later fault-planes are transverse and have displaced the veins and rendered the deposits more or less discontinuous.

The appearance of schistosity in the massive rocks seems to be limited to the immediate vicinity of the zone of veination

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