BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 1, pp. 99-162. pl. 2 March 13, 189o 



NOTES ON THE SURFACE GEOLOGY OF ALASKA 



BY ISRAEL C. RUSSELL 



[Read before the Society, December 26, 1889) 



CONTENTS 



Page 



Introduction 101 



Nomenclature of the Yukon and its Tributaries 104 



Geological Structure of the Y^ukon Region 108 



Monoclinals 108 



Faults 108 



Joint-valleys -- 109 



Bluffs on the Upper Yukon ' 109 



Geology of the Yukon River HO 



The Delta of the Yukon HO 



General Character HO 



Drift Timber 11° 



Surface of the Delta m 



The Banks of the Y'ukon u ' 2 



Erosion of the Right Bank 1'- 



Lower Ramparts H^ 



Lowlands 112 



Highlands of the Upper Yukon 1H 



The Water of the. Yukon 115 



Muddy and Clear Tributaries H & 



Sediment in Suspension H" 



Geological Records now being made by the Yukon 116 



The River in Winter n JJ 



Spring Freshets *™ 



Rock Surfaces polished and scratched by River Ice 117 



Bowlders transported by River Ice ] 



Gravel Heaps deposited by River Ice ] 



Pebbles faceted, polished and scratched by River Ice 119 



"Bowlder Clay" deposited by Rivers 



Old Deposits of ice-borne River Gravels 



Flood-Plain Deposits _" 



Mammoth Remains in the Banks of the Y T ukon I 22 



Extinction of the Mammoth 



Preservation of Fish Remains '- 



Navigation of the Yukon and its Tributaries v2i 



XIV— Bum,. Geol. Soc. Am., Vol. 1,1889. *• ' 



