86 GEOLOGICAL SURVEY OF THE TEERITORIES. 



ridge flow in a general eastward direction, joining here and there, and 

 within the limits of the district find their way into the South Platte. 



In the western half of the district the drainage is somewhat different, 

 though still very simple. The main divide not only passes through the 

 center of the district, but, at the north, turns westward along its northern 

 border, while at the south it also turns westward, trending along the 

 southern border, thus inclosing the park on the north, east, and south 

 sides. From all sides of this natural rim the streams flow inward to 

 join the Grand Eiver, which flows east and west through. the middle of 

 the system, forming its main artery. All the waters thus find their way 

 out of this basin through the single caiion which the Grand has cut across 

 the Park range at about its middle point, and flow on westward to join 

 the Colorado Eiver and the Pacific Ocean. Upon the north the Iforth 

 Park gives rise to the North Platte ; upon the south the South Park 

 gives rise to the South Platte, and both flowing eastward their united 

 waters finally join the Missouri. The Middle Park i^ thus inclosed by a 

 great eastward loop of the main continental divide, and it forms the 

 easternmost point north of Mexico at which waters flowiug into the Pa- 

 cific take their rise. 



PRINCIPAL TOPOGRAPHICAL FEATURES — MAIN DIVIDE. 



The crest of the m.ain divide crosses the northern line of the district 

 in longitude 105° 45' west, or at about midway of its length. From 

 this point its trend for ten miles is southeast to near Long's Peak, 

 where it turns directly southward, but with an undulating course, a 

 distance of sixteen miles, to Arapahoe Peak. Along this line, the 

 range is an exceedingly formidable one, and presents all the features of 

 mountains composed of granitic and schistose rocks. 



The eastern face of the crest presents an almost continuous line of 

 amphitheaters and gorges rimmed with precipitous walls, which rise to 

 a serrated crest of which many points reach an altitude of between 

 thirteen and fourteen thousand feet above sea-level, while not a single 

 pass exists except such as the most expert mountaineer might with 

 difficulty ascend. Some of the higher j)oints exist as eastern spurs 

 somewhat detached from the main ridge ; such are Long's Peak, (14,270 

 feet,) Mount Audubon, (13,190 feet,) and Smith's Peak, (13,090 feet,) on 

 either side of which are the deep-cut gorges, reaching past them to the 

 steep clifl's beyond, at the bases of which the banks of everlasting snow 

 are constantly eating their way farther and farther into the range. 



Upon the northeast side of Long's Peak, forming its very face, is a 

 sheer, almost perpendicular, cliff, over 3,000 feet in the clear, reaching 

 from the mountain-summit to the timber-line, the grandest wall of rock 

 imaginable. 



The western side of the main divide does not present so well-defined 

 a ridge. Instead, it is lined by a zone of high mountains, from five to 

 ten miles across, which falls abruptly, though not precipitously, to the 

 great trough-like valley of the Upper Grand. It is cut by profound 

 caiions draining into the latter. Upon the southwest, this rugged mass 

 is sharply limited by the East Fork of the Grand, while Arapahoe Peak 

 forms its southern apex. From Arapahoe, for twelve miles directly 

 south to James Peak, the topography changes. The crest presents a 

 very uniform ridge rising but little above timber-line, and for five miles 

 near the southern portion scarcely varying 200 feet in altitude. As at 

 the north, the eastern face of this ridge is precipitous, falling in great 



