568 CHIN 
sand is found along the beach just north of Valparaiso, and also to the 
north of the beach of Vira del Mar. 
The veins are of every size, from the merest line to several yards. 
The same vein (figs. 6, 7) is often very irregular in its dimensions, 
occasionally enlarging to an extensive bed, and again diminishing to 
a narrow thread. ‘The broadest vei 
one place and a foot in others. ‘They are also variously curved, and 
sometimes abruptly bent and faulted. 
The material of these veins is generally a feldspathic granite, 
coarsely crystallized, containing but little quartz, and the mica in 
rather large crystals. The feldspar is white or flesh-red, becoming 
sometimes brick-red near epidote veins. Quartz veins are not com- 
mon, though occasionally seen on the hill back of Valparaiso and 
elsewhere. Others of granular feldspar and compact talc, white or 
slightly greenish in colour, have been described as occurring in 
Mellaca Hill. 
The hornblendic schist to the southwest of Valparaiso, below the 
lighthouse, intersects the granite like veins or dikes, as has been 
described on a preceding page. ‘The same is true of the schist north 
of Vina del Mar. Some of the veins are narrow and tortuous, and 
their black colour causes them to stand out in strong contrast with 
the light tint of the inclosing granite. 
Structure.—There are many points of an interesting character in 
the structure of the larger granitic veins, and the including rock. 
