VI PREFACE BY THE EDITOR. 



for the first, and it was omitted. The second was largely foreshadowed by 

 scattered allusions in the preceding sections, and as it must consist in any 

 event chiefly of simple deductions from the facts set forth in the descrip- 

 tions of the formations, its composition was undertaken by the editor. 

 The thoroughness and fidelity of the record of observations and its freedom 

 from bias made the task an easy and pleasant one. All the data are New- 

 ton's, and so are all the principal deductions except those derived from the 

 drainage system, but he should not be held responsible for the manner of 

 presentation. 



The majority of the wood-cuts illustrating his text were made under 

 his own direction with the friendly assistance of Mr. J. L. Fitch, and others 

 were afterwards prepared for the engraver by Mr. Thomas Moran. The 

 topographic map and the base of the geological map were drawn by Dr. 



V. P. McGillycuddy, the topographer of the expedition. The colors of the 

 geological map, unfortunately, have not the author's full authority. He 

 traced the outlines of the formations rudely upon a small and imperfect 

 map prepared for the preliminary report, but the final map was printed too 

 late to be used by him. The editor transferred the colors from the small 

 map to the large, and filled in the details, so far as he was able, to corre- 

 spond with the descriptions given in the manuscript, but it is to be supposed 

 that he fell into many errors which the author would have been able to 

 avoid. The bird's-eye view, although projected by Newton and drawn 

 under his supervision, was not engraved until after his death. 



The editor's responsibility does not extend to the chapters which succeed 

 Mr. Newton's. Mr. Jenney's chapters have already been published in a 

 preliminary report, and are here copied verbatim from that text. In its 

 separate publication his chapter on the Mineral Resources was introduced 

 by a general account of the geological structure, which is here omitted 

 because it is superseded by Mr. Newton's chapters. Mr. Jenney has sub- 

 stituted for it a brief classification of the auriferous formations. 



At the time of this writing, the editor is called away from Washington, 

 and confides the general supervision of all the text beyond Chapter III to 

 Mr. J. C. Pilling, of the Bureau of Ethnology. The proofs of Chapters 



VI, VII, VIII, and IX will be submitted to their authors. 



