l'i" I. C. RUSSELL URFACE GEOLOGY OF ALASKA. 



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Page 



l i 125 



logy of thi overed Shores of Alaska -_. 126 



Definition 125 



i I neral Characters 125 



M de of Formation l- ,; 



A | — ible Origin of Coal Seams 127 



tea "ii the Tundra l- s 



Stratified Cce in the Tundra — 128 



\| ■ ---. Covering of the W led Portion of Alaska 129 



I l stribution of the Mossy Covering I-"- 1 



Depth of the Frozen Stratum beneath the .Muss 129 



Depth of Frost in the Arctic 130 



The Frozen Moss-layer as a Geological Agent — — 182 



: Rocks 133 



igraphical Distribution of Rock Decay 133 



Absence of pronounced Bock Decay in Alaska 134 



aparison with other Regions 134 



Disintegration of Rocks 135 



G g iphical Distribution of Rock Disintegration 135 



Observations in Alaska 135 



I I bris Streams 135 



Talus Slopes or Screes 136 



Absence of Debris in the Glaciated Region 136 



Amount of Disintegration l ; >7 



Glaciation 137 



Previous Explorations — 137 



Personal Observations 138 



Dnalaska 138 



Absence of Glacial Records about St. Michaels 140 



-ence of Glacial Records along the Yukon l' n 



Absen f Glacial Records along the Porcupine ill 



The Snow Line 141 



Glaciation of the Upper Yukon Region ill 



Previous Explorations 1 1 1 



Upward Deflection of Glacial Grooves 142 



Freshness of the Glacial Records 142 



Bowlder Clay ... L48 



Direction of Ice Movement 148 



Northern Limit of Glaciation ill 



I __. _. I II 



earn Terraces along the Yukon i 1 1 



Dust in Stream Terraces. L45 



Plateau Ti 146 



Lake Terrai ■ - 146 



l i i on . . .. ... . 146 



Previous 148 



Position and 1. .. 146 



D hown bj I NT 



