Routes and rocks; hiker's guide to the North Cascades from ... - USGS

SUIATTLE RIVER 33To continue on the high route, climb steeply south from the meadowsat the head of Dolly Creek to the ridge above Vista Creek. Cross theridge high amid the uppermost trees (5850) and traverse above thebrushy and cliffy spurs extending down on the Vista Creek side. Thendescend a draw on the talus and the scree to Vista Creek. Bear towardthe high cliff of andesite where goats prowl.At the bottom of the slope is an outcrop of conglomerate, rich inboulders of gneiss, schist, and granite. At this place the young lava ofGlacier Peak spilled out on a slope covered with these boulders of olderrock (Fig. 11).[13]BRJECCIA(Schist fragments in granite )Figure 12BRECCIATED SCHIST(Also called breccia)SCHISTIn the early season the crossing of VISTA CREEK (4900-5 hours) maybe difficult, but late in the summer hop across on boulders. Head downstreamon the southeast side and go around the lower end of a sharpridge of fresh moraine (4900). Then go straight up the valley side inheavy timber (a little brush lower down) to reach the edge (5500) ofan open basin blanketed with heather. There are good camping spots onknolls next to gullied pumice. Northwest of the main stream in thisbasin are large meadows (5300).Conspicuous and cliffy Gamma Peak (7009) on nearby Gamma Ridgeis off to the southeast. Do not cross the ridge at the lowest saddle justwest of the peak but at the broad saddle about a mile to the west whichis marked by white pumice banks and lavacliffs. Here in the saddle(6650-7 hours) ends the GAMMA RIDGE TRAIL.The hiker standing in the broad saddle overlooking Dusty Creek is inthe midst of well-displayed geologic features (Fig. 13). To his right (west)at the head of Dusty Creek is a great cleaver, consisting of tall verticalcolumns of jointed Glacier Peak lava.- This lava rests on older, yellowrock consisting of layers of volcanic ash and volcanic breccia (Fig. 3).The ash, when solidified into a more or less solid rock, is called TUFF.[14!