ALASKA-TREADWELL MINE 
65 
suggesting a variety allied to glaucophane. Patches of 
the rock are wholly made up of granules of bright green 
epidote, which give a greenish mottling to the hand speci¬ 
men. Cloudy areas full of minute black specks which 
may be magnetite are numerous. Numerous round or 
oval spots in the section, lined with quartz or feldspar and 
filled in with grains of calcite, strongly suggest amygda- 
loidal cavities in a lava; and it seems quite likely that the 
schist represents a completely metamorphosed eruptive 
rock. 
In the canyon of Gold Creek immediately back of Ju¬ 
neau was found a series of greenstone schists of consider¬ 
able extent. Of the many varying phases seen in this 
series the following varieties were collected: 
No. 22, actinolite-schist , a very compact fine-grained schist of 
light green color, showing many slickensided surfaces covered with 
chlorite. In the section it is seen to be composed almost wholly of 
rather short prisms of actinolite, with quartz grains filling the inter¬ 
spaces. A little epidote in small grains and an occasional titanite 
grain are also present. 
No. 23, actinolite-schist , very like the last, but charged through¬ 
out with minute and very sharp octahedrons of magnetite. 
No. 341, actinolite-schist , the surface showing oval areas of chlorite, 
which give it a spotted appearance. 
No. 25, schistose diorite-forfhyry (actinolite-schist), a rock of 
schistose texture but distinctly porphyritic with white dots in the 
greenish matrix. Under the microscope the porphyritic spots appear 
as sharply marked areas containing aggregates of needles of zoisite 
and actinolite, with quartz filling the interspaces. The groundmass of 
the rock is a finely felted aggregate of actinolite needles with epidote 
and quartz grains. The appearance indicates pretty certainly the deri¬ 
vation of the rock from a diorite-porphyry by dynamic metamorphism. 
In the schists are occasional quartz lenses in which are 
siderite and granular epidote and at times masses of fine 
scaly chlorite (delessite). 
At one point on the road a dike of aftlite was found, 
