666 G. K. GILBERT 



His more important additions to knowledge are in the fields of 

 descriptive geology, dynamic geology, and physical geography. He 

 described the Newark formation in New Jersey and Virginia, the 

 Quaternary lakes of the northwestern part of the Great Basin, the 

 recent faults and block mountains of part of the same region, and 

 the surface geology or general geology of various areas in Washington, 

 Oregon, Idaho, Utah, Michigan, and Alaska. He wrote on the 

 origin of the red color of certain sedimentary formations. He dis- 

 cussed the nature of massive solid eruptions, and proposed a genetic 

 classification of igneous intrusions. He studied and described 

 glaciers in the Cascade region and Sierra Nevada, and about Mount 

 St. Elias, Yakutat Bay, and Glacier Bay; discussed cirques, and the 

 influence of incorporated debris on glacial flow; and added to the 

 nomenclature of glaciers the now familiar term "piedmont." He 

 treated of the genesis of tundras and the natural history of playas, 

 playa lakes, and playa deposits. 



His wide range of first-hand knowledge abundantly qualified 

 him for five works involving extensive compilation, and his simple 

 and attractive literary style made them acceptable to a wide range 

 of readers. Four of these pertain severally to the rivers, lakes, 

 glaciers, and volcanoes of North America, and are called "reading 

 lessons for students of geography and geology;" the fifth is a general 

 treatise on the geography of the continent; and all are recognized 

 as standard works. 



Russell was pre-eminently a scientific observer. His best work 

 was in seeing, recording, and discussing the phenomena of a new 

 field. His observation was sharpened by loiowledge of existing 

 theories, but not biased by them. He was not a theorist seeking 

 confirmatory facts, but an observer seeking explanations of the 

 thing seen. His contributions to the body of scientific philosophy 

 were many, but were not of the broadest scope, because they were 

 largely restricted to the field of his own observation. His contri- 

 bution to the body of scientific fact was exceptionally large, pri- 

 marily because he was keen, energetic, and industrious, but also 

 because he was content with immediate explanations and did not 

 delay publication to search for the broadest generahzations. By 

 promptness in publication he doubtless incorporated some errors 



