viii CONTENTS. 



Chapter [II.— Post-Laramie and Tertiary geology— Continued. Page. 



Section II.— Denver formation, by Whitman Cross— Continued. 



Sources of materials in the sediments 199 



Areheau debris 200 



Sedimentary rocks 200 



Erupture debris 201 



Section III.— Age of the Arapahoe and Denver formations, by Whitman Cross 206 



Statement of the question 206 



Evidence of lithologic constitution 209 



Evidence of stratigraphic relations 212 



Evidence of allied formations 213 



Evidence of fossil plants --- 



Evidence of invertebrate fossils 226 



Evidence of vertebrates 226 



Conclusions from evidence 244 



Section IV.— Monument Creek formation, by George II. Eldridge 252 



Stratigraphy 252 



Lite 254 



Stratigraphical tela lions 254 



Chapter IV.— Pleistocene geology, by S. F. Emmons 255 



Earlier erosion epoch 256 



Loessial epoch 258 



River drift 258 



flu vial loess 260 



The loess 261 



Grlacio-natant drift ; 265 



Upland drift 266 



Modern erosion epoch 266 



Economic features of the Pleistocene deposits 2ti9 



River drift 269 



Placer gold 269 



Water 272 



Loess 272 



Soil 272 



Water 273 



Brick clays 274 



i irigin of the loess , 274 



Chapter V. — Igneous formations, by Whitman Cross 279 



Section I. — Geological occurrence 279 



Introduction 279 



Basalt 279 



The Valniont dike 280 



The Ralston dike 281 



Hills between the Ralston dike and Table Mountain 283 



The surface flows of Table Mountain 285 



The basalt ic. capping 285 



The earliest basaltic outflow 290 



The zeolitie minerals of Table Mountain 292 



