2 TO ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the Arkansas, Gunnison, and Uncompaligre Rivers, expecting 

 to occupy six main triangulation stations necessary to connect 

 the belt established in Colorado in 1873 to the southward. 

 In their movements they were so fortunate as to discover an 

 original pass through the main ridge or backbone of the 

 Rocky Mountains, which may be described as follows : 



It is just south of Hunt's Peak, near the head of the mid- 

 dle fork of Poncho Creek, to the head-waters of the Gunni- 

 son. It is lower than all others across the Pacific divide in 

 Colorado save the Coochetopa, and is superior to all save the 

 Coochetopa and the Tennessee. A good wagon road, with 

 an average grade not exceeding 212 feet to the mile, can be 

 constructed over it ; and from Pueblo, Canon City, Denver, 

 or the Upper Arkansas, it will cut oil' nearly eighty miles in 

 the distance to the Gunnison River and the mines at its head. 



Lieutenant Marshall and party visited Pagosa Springs about 

 the 10th of October for supplies, and thence via the head- 

 waters of Cornejos and Las Animas or Purgatore Rivers reach- 

 ed Trinidad, where the season was closed, and a base was meas- 

 ured, the same having been commenced late in November. 

 The number of miles traveled by this party was 2456. 



The party under Lieutenant Blunt, accompanied by two 

 topographers, one meteorologist, and one odometer recorder, 

 occupied the area bounded on the north by the latitude of 

 Trinidad, west by the summit of the main range leading 

 southward to Las Yegas, New Mexico ; thence east along the 

 parallel of Las Vegas to the meridian bounded by 104 07' 

 30". This comprises a part of the basins of the Cimarron, 

 Mora, and Pecos Rivers. The country about the head-waters 

 of these streams proved especially rich in topographical ma- 

 terial entirely new to geographical science, and their detail- 

 ed work joined that of the parties to the westward. 



The party under Lieutenant Price, Corps of Engineers, as- 

 sisted by three topographers, one meteorologist, and one miner- 

 alogist and chemist, occupied a line so chosen as to reach the 

 number of main triangulation stations selected for them, and 

 an area for minute survey bounded on the north by the lat- 

 itude of Tierra Amarilla, south by the latitude of Las Vegas, 

 west by longitude 108 15', and easterly by the area occupied 

 by the party under Lieutenant Blunt. Part of their duties 

 consisted in measuring base lines at Santa Fe and Las Vegas. 



