CONTENTS. 5 
Page. 
The Treadwell ore deposits, etc. — Continued. 
The ore bodies — Continued. 
The ores 77 
General description 77 
Shape of the ore bodies 78 
Persistence in depth 79 
Veining in the ore bodies 79 
Gangue minerals 81 
Metallic minerals 81 
Occurrence of gold 82 
Metasomatic alteration 83 
Role of the basalt dikes 84 
Origin of the fractures 85 
Source of the vein-forming waters 86 
Summary 87 
Cape Yaktag placers, by George C. Martin 88 
Introduction 88 
Geology , 88 
Occurrence of gold 89 
Gold placers of Turnagain Arm, Cook Inlet, by Fred H. Mopfit 90 
General statement. 90 
Geography 90 
Geology 93 
Gold 94 
Placer deposits 95 
Resurrection Creek district 95 
BearCreek 95 
Palmer Creek 95 
Sixmile Creek district 96 
Canyon Creek 96 
Mills Creek 96 
Glacier Creek district 97 
Crow Creek 97 
Cooper and Stetson creeks 98 
Character and origin of the placer gold 98 
Auriferous lodes 98 
Bear Creek 98 
Sawmill and Slate creeks 98 
Copper 99 
Gold deposits of the Shumagin Islands, by George C. Martin 100 
Apollo consolidated mine 100 
Location and output 100 
Previous work 100 
Character 100 
Age 100 
Neighboring deposits 101 
Sand Point beach-placers 101 
Gold mine on Unalaska Island, by Arthur J. Collier 102 
Introduction 102 
Topography 1 02 
Geology 1 02 
Quartz veins 103 
Development L03 
