278 KEPOET UNITED STATES GEOLOGICAL SURVEY. 



then left one at Fort Garland, to be observed every half-hour during 

 the middle of the day, the fort being only 10^ miles in a straight line 

 from the peak. A mean of the eight barometrical results for the differ- 

 ence between the peak and Fort Garland gave6,4G6 feet, while, by fore 

 and back angles of elevation and depression, the difference was 6,408. 



Fort Garland was first determined by a series of readings extending 

 over some three or four months, taken three times daily, compared with 

 those taken at Colorado Springs by the signal service. A mean of all 

 these results gave for Fort Garland a height of 7,997. 



Later I procured the i^reliuiinary profile of the Denver and Eio Grande 

 Eailroad, which gave to the fort an elevation of 7,946 feet. Assuming this 

 to be correct, it gives for Blanca Peak an elevation of 14,413 feet above 

 sea-level, making it the highest point in Colorado, according to our ob- 

 servations. But owing to the fact that a number of points so nearly ap- 

 proach this figure, and to the imperfections in the barometer as an 

 instrument for the measurement of heights in a mountainous region, 

 ^vhere local storms and sudden atmospheric changes occur so frequently 

 jis in Colorado, it is a very difficult matter to determine with certainty 

 which is the highest peak. Another cause for uncertainty in the ab- 

 solute heights of ail points in the far West is, the poor quality and the 

 wantof proper connection between the railroad levels run from the Gulf 

 and the Atlantic seaboard by many different roads, and by many differ- 

 ent persons. But as these levels afford the best determination which wo 

 have for the interior, we were compelled to base all our heights on them. 

 Until some continuous line is carried through from tide- water, this un- 

 certainty cannot be removed; consequently the absolute heights of all 

 points in the interior must remain to some extent unsettled for the 

 present. 



From Fort Garland we marched westward across the San Luis Yal- 

 ^^Ji t)y ^ay of Del Norte, to the Summit district, where another station 

 was made on Summit Peak ; thence, following up the Eio Grande we 

 made our next station on Eio Grande Pyramid, a fine pyramidal peak 

 situated a few miles south of the river, on the continental divide. 



Our next point being the highest peak in the La Plata group, we 

 marched by way of Silvertoo, thence by trail down the Animas Eiver to 

 Animas Park and ParrottCity. From thelatter place we skirted the west- 

 ern slope of the mountains to the foot of our objective point, and on 

 September 12 we ascended Hesperis Peak. Arriving at the summit we 

 found the day to be one of those magnificently clear days which are 

 only found in these high regions, and which can only be fully appreci- 

 ated by one doing such work as ours, where it is so necessary to see 

 points at such great distances. After spending some four or five hours 

 busily taking notes, we returned to camp well pleased with the results, 

 and on the following morning resumed our march toward the northwest, 

 camping the first night at the Big Bend of the Dolores. 



Our next point being the Abajo Peak, which wa« some eighty miles 

 to the west, consequently out of our direct line of march, I determined 

 to divide my little party, sending the main train on to await me under 

 Lone Cone, while Mr. Holmes and myself took a small outfit and started 

 across the mesa country for the Abajo Mountains, making a few topo- 

 graphical stations on the way to fill in a small area which had been left 

 the previous year owing to the hostilities of the Ute Indians. 



The second day's march brought us to the foot of the mountains, but 

 at the same time a storm which had been accumulating for some time 

 broke upon us, and as we were not prepared for such an event, were 

 compelled to hover around a sage-brush fire for three days, while the 



