12 GEOLOGICAL SURVEY OF THE TERRITORIES. 



were very difficult of access, and resembled swallows' nests more than 

 anything else. To reach these with the photographic apparatus, it had 

 to be hauled up with long ropes taken from the pack-animals. From 

 near the mouth of the Eio Mancos, the party proceeded northwesterly 

 into Utah, finding group after group of towns and isolated watch- 

 towers perched upon great bowlders and upon the promontories of the 

 mesas. In one place was found a wall, evidently surrounding a town of 

 a very considerable population, which was fully twenty feet in thickness, 

 the outer surface of dressed stone, laid perfectly true, thd space 

 between filled with large undressed blocks in adobe mortar. 



The entire trip to these ruins, from and back to Baker's Park, com- 

 prised about three hundred and fifty miles of traveling. Only two 

 weeks could be devoted to it, which necessitated a somewhat super- 

 ficial examination. Two series of views were made, the stereoscopic 

 and five-by -eight plate. About forty negatives were made altogether, 

 illustrating perfectly all the leading features in a very unique series of 

 views. 



From Baker's Park, the party returned by rapid marches, via the Eio 

 Grande, San Luis Valley, and Mosca Pass, to Colorado Springs, where 

 they met with the special party under my charge. Mr. Jackson joined 

 him with his apparatus for a few days, while his party proceeded to 

 Denver and disbanded. The four or five days he was with the special 

 party, about one hundred additional negatives were made, mostly of 

 camp-life and the manner of conducting the various operations of the 

 survey while in the field. The result of the trip sums up as follows: 

 350 negatives, stereoscopic and five-by-eight, and the most extensive 

 and interesting conchological collection ever made in the Territories. 

 The party was out eighty-four days, making sixty camps, and traveling 

 one thousand two hundred and forty miles. 



Not a negative was broken or lost on the trip, and the naturalist's 

 and different zoological and entomological collections came in safe. 



The work of the survey during the season of 1875 will be extended 

 westward in Colorado to the meridian of longitude 109° 30'. The area 

 now remaining to be explored lies west of 108° on the western slope of 

 the main range of the Bocky Mountains and comprising the eastern por- 

 tion of the drainage of the great Colorado Eiver. Hundreds of streams 

 of greater or less size cut deep gorges through this country in their 

 westward course to the Colorado Eiver. There are some groups of 

 mountains yet to be surveyed, but the highest peaks have already been 

 located. 



According to the instructions given by the Department : 



First. There shall be two classes of maps: one known as "general", the other as 

 "special" maps; and the "general" maps shall be subdivided into two classes, viz, 

 " topographical " and " geological". 



Second. The " general " maps shall be on a scale of four miles to an inch, or zg3 1 4 40 . 

 The sheets thereof shall be twenty-six (2G) inches long by thirty-seven (37) inches 

 wide, including the border, and be folded once. The area to be represented on each 



