518 The National Geographic Magazine 



have done the greater work in not only 

 carrying away the debris that falls from 

 the cliffs, but in gouging out canyons 

 and cutting back into the bowels of the 

 mountain itself. The amount of cutting 

 going on at present is not inconsiderable, 

 and from it one gets an idea of what it 

 must have been during the periods of in- 

 finitely greater glaciation. 



The wide U-shaped valleys of the 

 Sandy and the Zigzag rivers are plainly 

 glacier-sculptured. The intense foresta- 

 tion has covered up and the heavy rain- 

 fall has washed away much of the evi- 

 dence, but in the valley floors one sees 

 many large angular boulders which ap- 

 pear" to be of drift origin. These were 

 found as far down the Sandy Vallev as 

 the right-angle bend below Cherryville, 

 where the river enters a canyon. On the 

 bench north of the junction of the Zig- 

 zag and Sandy rivers, called Crutchers 

 Mountain, the bed rock is deeply scored. 



The drift in the Sandy Valley above 

 the forks is much fresher in appearance 

 and more clearly glacial than that below. 

 The wagon road up the Zigzag above the 

 Tollgate runs over what is clearly rao- 

 rainal material all the way to Govern- 

 ment Camp and beyond. On its way it 

 climbs Laurel Hill, a ridge of old granite 

 rock which shows striae and polish. 

 Along the top of the ridge north of the 

 Sandy River, between Hood and Last 

 Chance Mountain, stretches the rem- 

 nants of an old moraine. 



In the park area between the White 

 River and the East Fork of Hood River 

 the rocks that are exposed are very hard, 

 and here again were seen beautiful striae 

 and grooves. 



How far this glaciation extended I do 

 not know. I found no trace of it west 

 of Cherryville, but at that place begin to 

 appear what I take to be the terraces of 

 the Willamette Sea of Pleistocene times, 

 and the plot becomes too complicated for 

 the novice. 



Permit me to call attention, however, 

 to the great cirques at the heads of the 

 various branches of the Bull Run River 

 and their comparatively low elevation. 

 A closer study of the map reveals lesser 



cirques in many places. The ice un- 

 doubtedly swept through the low passes 

 in the main divide at the head of Clear 

 Fork and Bull Run Lake ; also through 

 Lost Lake down the Lake Branch. 



These two lakes themselves offer much 

 of interest to the geologist. The former 

 was made possible by a fissure flow of 

 lava in the bottom of the canyon, where 

 now is the lower end of the lake, forming 

 a dam behind which the water collected. 

 This lava is unglaciated and is therefore 

 more recent than the great glacier that 

 carved out the canyon. The lake outlets 

 through the lava, not over it. The lake 

 level varies during the year as much as 

 ten feet. 



A DROWNED FOREST 



Lost Lake, on the contrary, does not 

 vary over a foot at most. It has a' fair- 

 sized outlet into Lake Branch. One sees, 

 -when navigating it, tree-tops far below 

 its surface. In other words, here is a 

 forest that has been drowned. Lost Lake 

 Butte, is an extinct volcano. A flow of 

 lava from it has probably dammed the 

 lake's outlet to the east, causing the basin 

 thus made to fill and overflow to the 

 north. Lost Lake when discovered con- 

 tained trout, though it is now impossible 

 for fish to come up Lake Branch into it 

 because of falls. Bull Run Lake has no 

 fish naturally, but white fish have been 

 introduced. The isolated ridge north of 

 Lost Lake is largely made up of a cinder 

 deposit in which volcanic bombs of 

 various sizes occur. 



ENORMOUS MASSES OE DEBRIS 



But, to return to our mountain, one of 

 its most prominent features is the fan- 

 like outwash on the southwest side. By 

 glancing at the map you will see that this 

 radiates from the gap in the crater's rim 

 and probably bears a distinct relation to 

 it. This whole side of the mountain, 

 reaching from the ridge east of the 

 White River Canyon to that between the 

 forks of the Sandy River, is deeply cov- 

 ered with glacial debris. The small can- 

 yons at the foot of the White River gla- 

 cier are trenched in this debris which 



