APPENDIX. 



features. Geology is revealed in topography. The details of 

 topography may seem simple, and taken severally may be simple, 

 but in groups they become extremely complex, and few persons 

 readily comprehend the order and system with which topographic 

 features are gathered about the great geological structure lines 

 of a region. It is easy to be lost in a maze of hills and a con- 

 fusion of mountain peaks unless the grand topographic forms on 

 which the hills and mountains are sculptured are seen with a 

 mental vision that reaches further than the eye. He who can see 

 a mountain range, or a river drainage, or a flock of hills, is more 

 rare than a poet. In anatomy there is a place for apophysis and 

 sinus, for arch and foramen ; so in a mountain range there is a 

 place for peak and valley, a place for amphitheatre and caiion, 

 and the geologist who seeks to reveal the embryology and growth 

 of a mountain range must first become thoroughly familiar with 

 its anatomy. A hill may be a hundred or five hundred feet high, 

 a mountain a thousand or ten thousand feet in altitude, and these- 

 may be interesting facts, but they give no clue to hill or mountain 

 structure, and have values of the same order as the size of animals 

 in systematic zoology. Not every geologist has been able to 

 understand the geography of a region studied, and very few 

 indeed have been able to describe the geography of a district. 

 Something more is needed than to make mention of mountains 

 and hills, of valleys and canons ; the order in which they are 

 arranged must be set forth, and their relations to the general 

 structure must be explained. 



Mr. Marvine went into a region which to the common eye would 

 seem but a wild confusion of mountains and valleys, of crags and 

 gorges, but in that single summer's study he discovered the sub- 

 lime order in which the mountains and hills and ridges were 

 placed, and in the first few pages of his report he sets forth this- 

 order in language clear and simple, giving a plain bird's-eye view 

 of all that five thousand square miles of mountain crag and caiion 

 gorge. Then he divides the area into three natural geographic 

 divisions, and hence geologically distinct ; the zone of ridges 

 separating the plains from the mountains or mountain border 

 region ; the great range and Middle Park. In the first he found 

 a series of sedimentary groups having a total thickness of more 

 than 1000 feet, and a natural grouping was first discovered; 

 then he studied the overlaps and out-thinnings, the changes in 

 conditions of sedimentation, the grand displacements due to or- 

 ographic movements, and the minor concomitant flexures and 

 faults. All of these facts he presents in orderly arrangement 

 with appropriate diagrams and sections. His chapter on this 

 topic is full of facts and yet it never wearies the reader, for every 

 fact has a meaning. The geological literature of America is 

 - greatly burdened with inconsequent facts : A geologist repairs 

 to the field, finds a sandstone, measures it and it is ninety-nine 



38 (5^> 



