436 GEOLOGICAL SURVEY OF THE TERRITORIES. 



the summit of the Front or Colorado range north of Long's Peak, west 

 to the Park range, which is the eastern limit of the bulk of our work, 

 and has a trend of north 25° west from Mount Powell. The disposition 

 of the country made it desirable to commence at the eastern end of the 

 North Park district, and to extend the work to the west toward our 

 supply depot at the White River Indian agency, and when, early in 

 November, we reached the country between the Mount Powell range 

 and the headwaters of the Eagle, the storms and the clouds that hung 

 constantly around the mountains made it impossible to continue the 

 work, and we were obliged to leave that portion for another season. 



The total area surveyed is about four thousand one huudred square 

 miles of mountain country, interspersed with a few wide, open valleys. 

 The methods of working are the same as adopted by the other parties. 

 A line of primary triangulation stations bordering the country on the 

 east and south and Dome Mountain near the center of the district, lati- 

 tude 40° 00' 57."45, and longitude 107° 04' 40."46, (approximate,) were 

 the points with which the secondary triaugulation joining all the topo- 

 graphical stations were connected. Eighty-six principal stations were 

 made, together with some minor compass stations along the lines of 

 travel. The average distance of the stations apart was 6.84 miles. 



A barometric station was established at the White River Indian 

 agency, commencing on the 17th of August, and a meteorological record 

 has beeu kept from that time to date. Different members of the party 

 were observers while the party was in the field, and since then the 

 observations have been made by Mrs. E. H. Danforth. 



A portion of the party was encamped at the mouth of the Eagle 

 River for twenty-six days, and a barometric record was kept there 

 during the time, which gives the elevation of that point very accurately. 



The station at the agency is the base used in the calculation of the 

 majority of the heights ; for the work done while the small side-party 

 was at the mouth of the Eagle, that base was used as being much 

 nearer, and the work done in the North Park previous to the establish- 

 ment of the White River base depends upon the bases at Fairplay and 

 Denver. 



The southern end of the Medicine Bow Mountains, which border the 

 North Park on the east, forms a high, precipitous, granite range be- 

 tween the valley of the North Grand and the Park. East of the North 

 Grand rise the mountains of the great Front range, of the fame gene- 

 ral character as they are to the south, sharp, serrated summits, with am- 

 phitheaters on either side. The highest points of these ranges rise to 

 a little over 13,000 feet, but the general elevation is 12,500 feet. To 

 the north the Front range loses its rugged Alpine character and changes 

 to a high, heavily-timbered plateau range, separated from the Medicine 

 Bow by the Big Laramie River, and drained on the east by the Cache 

 la Poudre. The range in the other direction bears south 40° east, and 

 culminates in the highest mountain of the whole northern district, 

 Long's Peak. The valley of the North Grand is narrow and close, ex- 

 cepting a portion of its lower course, where it widens into a broad 

 beaver meadow. 



Crossing the Medicine Bow range, we descend by long, broken spurs 

 to the broad open prairie-like basin of the North Park, drained by the 

 North Platte River. Across the Park rises the Park range, a broad, 

 rounded mass, heavily timbered, about twelve miles in width, and with 

 an elevation of from 10,000 to 10,500 feet. The range retains this 

 character for fifty miles to the south, and then rises to the very rugged 

 precipitous range of Mount Powell. To the north, for ten miles, it re- 

 mains the same, aud then changes to a more mountainous type, but not 



