CONTENTS 
Page. 
Letter of transmittal 7 
Introduction - ■ 9 
Geographic position 9 
History of recent exploration and development 10 
Purpose of this bulletin 12 
General geology 12 
Sedimentary rocks 12 
Surfieial deposits 14 
Igneous rocks 15 
Economic geology 16 
General statement 16 
Localities where lode tin has been found 17 
Lost River 17 
Cape Mountain 23 
Localities from which lode tin has been reported 25 
Diomede Islands 25 
Brooks Mountain - 26 
Don River 26 
Ear Mountain 26 
Hot Springs 28 
Asses Ears 28 
Localities where stream tin has been found 29 
Buck Creek 29 
Anikovik Creek and Buhner Creek 35 
Localities from which stream tin has been reported 36 
Summary of economic geology 36 
Transportation and fuel supply 37 
Tin ores and associated minerals - 39 
Physical characteristics of tin ore 39 
Associated minerals 40 
Tourmaline 40 
Garnet 40 
Rutile 40 
Wolframite 41 
Epidote 41 
Magnetite and limonite 41 
Fluorite 41 
Quartz 41 
Methods of assaying tin ore 41 
Occurrences of tin ore in the United States 44 
3 
