52 REPORT OF THE SECRETARY. 



merit of the Interior. These maps will be engraved on a scale of four 

 miles to one inch, and each sheet will embrace an area of about eleven 

 thousand five hundred square miles. The districts explored during- the 

 past year were not so mountainous as those of the previous year, but were 

 located in the most inaccessible regions of this continent. Much of the 

 country is drained bv the Colorado River and is mainlv a plateau country, 

 cut in every direction by deep gorges or canons, the sides of which show, 

 for geological investigations, admirable sections of the strata formiugthe 

 earth's crust. The topography was elaborated in great detail by the use 

 of the plane-table. The geological structure of the country was care- 

 fully studied and much material secured that will throw light on the 

 various problems which have perplexed geologists for years past. 



The exploration of the remarkable prehistoric ruins of Southern Col- 

 orado, glimpses of which were obtained the preceding season, was con- 

 tinued with great success. They were traced down the canons of the 

 Colorado River in New Mexico, Utah, and Arizona, and their connec- 

 tion established with the cliff cities of the Moquis of the latter Terri- 

 tory. Hundreds of cliff or cave dwellings of curious architecture and 

 many miles from water were found in the sides of the gorges, and the 

 ruins of extensive towns discovered in the adjacent plains, indicating 

 the former existence of a people far more numerous and advanced in 

 the arts of civilization than their supposed descendants of the pres- 

 ent day. A good collection of pottery, stone implements, the lat- 

 ter including arrow-heads, axes, and ear ornaments, &c, some pieces 

 of rope, fragments of matting, water-jars, corn and beans, and other 

 articles were exhumed from the debris of these dwellings. Many 

 graves were found, and a number of skulls and skeletons, that may 

 fairly be attributed to the prehistoric inhabitants, were added to the 

 collection. Of these ruins, many interesting sketches, plans, and pho- 

 tographs were made, and the materials were secured for an exhaustive 

 report on this subject, which will be given to the public at an early 

 day. 



The photographer of the survey also obtained a series of mountain 

 views on plates 24 inches long by 20 wide, or larger by several iuches 

 than any landscape photograph ever before taken in this country. 



The publications of the survey during the year 1875 consist of "The 

 Vertebrata of the Cretaceous Formations of the West," by E. D. Cope, 

 303 pages text, quarto, with 57 plates ; third edition of " Lists of Eleva- 

 tions West of the Mississippi," much enlarged ; second edition of " Cat- 

 alogue of Photographs ;"and " Bulletin of the Survey," in six numbers, 

 comprising 500 closely printed octavo pages, with 20 plates of sections, 

 maps, &c. 



The work of the Second Division of the United States Geological and 

 Geographical Survey of the Territories under the direction of Prof. J. 

 W. Powell, had arrived at the beginning of the year 1875 at a stage at 

 which it was deemed best that a review of the geology should be made 



