TABLE OF CONTENTS. 



INTRODUCTION. 



Pago. 

 Ueport of Dr. F. V. Haydex : 



Letter to the Secretary xiii 



PART I.— GEOLOGY. 



Report of C. A. White, M. D. : 



Letter of transmittal - 3 



Report on the geology of a portion of Northwestern Colorado : 



Chai^ter I. Introduction 5 



Chapter II. Surface features 7 



Mountains 7 



Drainage 8 



Parks and basins 9 



Chapter III. Classification, description, and discussion of the groups of 



strata 19 



The Silurian system 23 



Carboniferous system 24 



The Mesozoic age 2G 



Triassic period ' 26 



The Jurassic period 28 



The Cretaceous period 28 



The post-Cretaceous period 32 



The Tertiary period 34 



Eruptive rocks , : 39 



Chapter IV. Displacements 40 



Uplifts and upthrusts 41 



Flexures 48 



Concluding remarks 51 



Chapter V. Surface geology 62 



Relation of the valleys to geological structure and displacements of 



strata 52 



Scattered drift - Sfv 



Chapter VI. Material resources £9 



Eefokt op F. M. Endlich, S. N. D., Geologist of the White River Division : 



Letter of tra,nsmittal 61 



Report on the geology of the White River District : 



Introduction 63 



Chapter I 65 



Drainage 65 



Topography 6(5 



Vegetation 68 



Chapter II. General geology 70 



Stratigraphy 71 



Jura Trias 72 



Cretaceous 74 



Post-Cretaceous 77 



Tertiary 78 



Ancient glaciers 86 



Ancient lakes 87 



Drift 88 



Chapter III. Correlations of stratigraphy, lithological constitution of 



strata and orography 90 



Crystalline aggregates 91 



Sedimentary rocks 9:5 



Eruptive rocks 97 



Special features 101 



Drift 102 



Conclusion 103 



III 



