fi CONTENTS. 
Analyses — Continued. p age . 
Igneous and crystalline rocks — Continued. 
Lake Superior region — Continued. 
4. Penokee-Gogebic region 73 
5. Rocks of Pigeon Point, Minnesota 76 
6. Miscellaneous rocks from Minnesota 81 
South Dakota 84 
Wyoming 85 
Yellowstone National Park and the Absaroka Range 87 
1 . Electric Peak 87 
2. Sepulchre Mountain 90 
3. Absaroka Range 92 
First. Crandall Basin 92 
Second. Sunlight intrusives . . _ _ 95 
Third. Ishawooa intrusives 96 
Fourth. Dikes in breccia 97 
4. Absarokite-shoshonite-banakite series 99 
5. Miscellaneous rocks 104 
Montana Ill 
1. Madison and Gallatin valleys Ill 
2. Butte and Boulder districts 116 
3. Crazy Mountains 120 
4. Little Belt Mountains 124 
5. Castle Mountain district 129 
6. Highwood Mountains 131 
7. Little Rocky Mountains 134 
8. Bearpaw Mountains 135 
Idaho 137 
Colorado 140 
1. Denver Basin 140 
2. Pikes Peak district 141 
3. Silver Cliff and Rosita 147 
4. BuffaloPeaks 153 
5. Leadville region 154 
6. Tenmile district 157 
7. Elk Mountains 159 
8. West Elk Mountains 160 
9. San Juan region '. 161 
10. Miscellaneous rocks _ 164 
Utah 166 
1. Rocks from the Tintic district 166 
2. Rocks from the Henry Mountains 161 
3. Miscellaneous rocks 168 
New Mexico 169 
1. Basalts from the Rio Grande Canyon 169 
2. Mount Taylor region 170 
3. Colfax County . 171 
4. Miscellaneous rocks 172 
Arizona 173 
Nevada 174 
1. Rocks from Washoe 174 
2. Rocks from Eureka 175 
California 176 
1. Mount Shasta - 176 
