1877.] Explorations in Colorado. 73 
EXPLORATIONS MADE IN COLORADO UNDER THE 
DIRECTION OF PROF. F. V. HAYDEN IN 1876. 
OR reasons beyond the control of the geologist-in-charge, 
the various parties composing the United States Geological 
and Geographical Survey of the Territories did not commence 
their field work until August. Owing to the evidences of hos- 
tility among the northern tribes of Indians, it was deemed most 
prudent to confine the labors of the survey to the completion of 
the atlas of Colorado. Therefore the work of the season of 1876 
was a continuation of the labors of the three preceding years, 
westward, finishing the entire mountainous portion of Colorado 
with a belt fifteen miles in width of Northern New Mexico and 
a belt twenty-five miles in breadth of Eastern Utah. Six sheets 
of the physical atlas are now nearly ready to be issued from the 
press. Each sheet embraces an area of over 11,500 square 
miles or a total of 70,000 square miles. The maps are con- 
structed on a scale of four miles to one inch with contours of two 
hundred feet which will form the basis on which will be repre- 
sented the geology, mineral, grass, and timber lands, and all lands 
that can be rendered available for agriculture by irrigation. 
The areas of exploration are located in the interior of the conti- 
nent, far remote from settlements, and among the hostile bands 
of Ute Indians that attacked two of the parties the previous year. 
The point of departure the past season was Cheyenne, Wyo- 
ming Territory. The primary triangulation party was placed in 
charge of A. D. Wilson, and took the field from Trinidad, the 
southern terminus of the Denver and Rio Grande Railway, 
August 18th, making the first station on Fisher’s Peak. From 
this point the party marched up the valley of the Purgatoire, 
crossed the Sangre de Cristo Range by way of Costilla Pass, fol- 
lowed the west base of the range northward as far as Fort Gar- 
land, making a station on Culebra Peak. 
About six miles north of Fort Garland is located one of the 
highest and most rugged mountain peaks in the West, called 
Blanca Peak, the principal summit of the Sierra Blanca Group. 
On the morning of August 28th the party, with a pack mule to 
transport the large theodolite, followed up a long spur which 
Juts out to the south. They found no difficulty in riding to the 
timber line, which is here about twelve thousand feet above the 
sea-level. At this point they were compelled to leave the ani- 
mals, and, distributing the instruments among the different — 
