N0NMETALL1FER0TJS MINERALS, SOUTHEASTERN ALASKA. 77 
HAM ISLAND. 
Two deposits of marble have been developed to some extent on Ham 
island, an islet in Blake Channel at the southeast end of Wrangell 
island. The Woodbridge-Lowery property lies on the west side and 
he Miller property on the east side. Exploratory work has been 
idvanced at both localities, large blocks have been quarried, and from 
hem many tombstones have been chiseled and polished for local use. 
ADMIRALTY ISLAND. 
A number of marble deposits occur on Admiralty Island — at Marble 
fluffs on the west shore, at Square Cove, at Hood Bay, and in Chiak 
Say. Some of the marble at these points is of excellent quality, but 
nost of it contains silica and pyrite and is of an inferior grade. The 
leposits at Marble Bluffs are apparently the most extensive and of 
>etter grade than the others. 
OTHER LOCALITIES. 
Belts of marble exposed in cliffs at tide water have been located on 
he north side of George Inlet, also in Carroll Inlet to the southeast, 
>oth located on Revillagigedo Island. The extent and value of these 
narble beds have not been investigated. 
On the mainland to the north, at the head of Limestone Inlet, 30 
niles southeast of Juneau, extensive areas of a coarsely crystalline 
narble are located. The marble is colored and not of the best grade. 
GRANITE. 
DISTRIBUTION. 
The granitic intrusive rocks occupy about one-half of the aggregate 
and area of southeastern Alaska. (See PI. Ill, p. 48.) In composition 
hey vary from granite to granodiorite and to quartz or hornblende 
liorite. The core of the Coast Range, as well as the central portion 
)f many of the islands, is composed of this intrusive rock. The meta- 
norphism in the granite, its nonuniformity in color, and the presence 
)f joint cracks, so far as observed, make most of the stone undesirable 
! or building purposes. However, granite masses of good quality, uni- 
! orm in color, and favorably located for purposes of quarrying, were 
observed along the mainland up Portland Canal, in Behm Canal, at 
rhomas Bay, and Taku Inlet. On Baranof Island exposures of this 
:ock of similar good quality occur at Gut Bay, on the east side, and at 
^he head of Whale Bay and near Silver Bay, on the west side. 
CHARACTERISTICS. 
All the granite masses in southeastern Alaska are similar in compo- 
sition, having plagioclase feldspar as an essential constituent. Horn- 
blende is the usual dark mineral, though biotite mica is present in 
