22 NORTH AMERICAN FAUNA. [no. 16. 



streams. They average about a thousand feet in <lei)th, and their 

 slo])es are as steep as permitted by the unstable material through 

 which they are cut — usually pumice, gravel, and fragments of lava. 

 Owing to the fact that all of the great glaciers are on the north, east, 

 or southeast sides of the mountain, the canyons nuule by their rivers 

 are necessarily on these sides also. The only one of any size which 

 does not come from a glacier is Diller ranyon. on the west side of 

 Shastina. 



In most, if not all, cases the bottoms of the canyons in their upper 

 courses are bridged for long distances by masses of ice and snow — the 

 dumps of avalanches. I>elow these snow bridges are vast accumula- 

 tions of loose stones, which in several instances, as in Brewer, Bolam, 

 and Whitney canyons, are piled itp in a curious nuinner. During 

 periods of higb water the rocks that fall in are carried down by the 

 torrent and deposited on each side in banks several feet high, so that 

 the traveler on reaching the bottom has to climb up over a ridge of 

 loose stones and down again before coming to the stream. These lat- 

 eral ridges form miniature canyons in the bottoms of the big ones. 

 Most of the canyons have falls several hundred feet high in their upper 

 courses, and some have other falls farther down. Notable falls are 

 found high up in the canyons of ^Tud Creek, Ash Creek, Bolam Creek, 

 and Whitney Creek. While diflicult of access, they are well worth the 

 effort of a visit. 



Mud Creek Canyon (pi. in)-, the only one likely to be seen by the 

 ordinary visitor to Shasta, is not easy to cross except near the mouth 

 of Clear Creek, which comes into it from the east. Its east bank is a 

 precipitous single slope about 1,000 feet in height. Its west bank, 

 except above timberline, is broken by a forest- covered terrace or bench, 

 and both descents are likewise steep, though less diflicult than the oppo- 

 site side. The canyon of Ash Creek is better timbered and a little less 

 precipitous than that of Mud Creek. The canyons of Bolam and Whit- 

 iu»v (Greeks, like that of the ui)pcr part of Mud Creek, are territic naked 

 chasms, very deep and so steep that in most places the loose material 

 of their sides will not sustain the weight of a man — much less that of a 

 horse — and when disturbed dashes in avalanches to the bottom. 



Diller ( 'anyon is peculiar (pi. iij. It is a tremendous gash on the west 

 side of the otherwise symmetrical cone of Shastina, whicli it cleaves 

 from to}) to bottom before taking its practically siraiglit westerly 

 course down the rest of the mountain. It is the only canyon on Shas- 

 tina, the only notable one on the west side of Shasta, and the only one 

 anywhere on the mountain that does not enmnate from a glacier. Its 

 stream comes from enormous banks of perpetual snow. 



A\'hile the upi)er i)aits of the <-anyoiis are exceedingly steep and 

 barren, and pra<;tically devoid of vegetation, the middle and lower 

 parts are invaded by the trees of the adjacent sloi)es, and in marshy 

 and springy si)ots contain patches of willows, ahleis. and a nmltitude 



