ADVERTISEMENT. 



DOCTOR WILLIAM H. SHERZER, Professor of Natural Science at Michigan 

 State Normal College, has brought together in the present memoir the results 

 of an expedition undertaken by the Smithsonian Institution among the glaciers 

 of the Canadian Rockies and Selkirk's in the year 1904. The general objects of 

 the research were to render available a description of some of the most access- 

 ible glaciers upon the American continent, to investigate to what extent the 

 known glacial features of other portions of the world are reproduced in these 

 American representatives, and to ascertain what additional light a study of 

 similar features here might shed upon glacier formation and upon some of the 

 unsettled problems of Pleistocene geology. 



A systematic survey was made of the Victoria and Wenkchemna glaciers in 

 Alberta and of the Yoho, Asulkan, and Illecillewaet glaciers in British Columbia, 

 located about two hundred miles north of the boundary of the United States. 

 The largest of these is the Yoho Glacier, extending more than three miles below 

 the ne"ve" field, and a mile in width for two-thirds of its length. Doctor Sherzer 

 investigated various surface features of each of these glaciers, the nature and 

 cause of ice flow, the temperature of the ice at various depths and its relation 

 to air temperature, the amount of surface melting and the possible transference 

 of material from the surface to the lower portion; their forward movement and 

 the recession and advance of their extremities, and the general structure of glacial 

 ice. 



In summarizing the most important results Doctor Sherzer discusses the 

 indicated physiographic changes in the region during the Mesozoic and Pleis- 

 tocene periods; the question of precipitation of snow and rain, and the effect of 

 climatic cycles on glacial movements, the structure of the ice as to stratification, 

 shearing, blue bands, ice dykes, glacial granules, and the possible methods of 

 their development. In discussing the theories of glacial motion the author 

 expresses his conviction that the nature of the ice movement can be "satis- 

 factorily explained only upon the theory that under certain circumstances and 

 within certain limits ice is capable of behaving as a plastic body, that is, capable 

 of yielding continuously to stress, without rupture," but "the plasticity of ice, 

 a crystalline substance, must be thought of as essentially different from that 

 manifested by such amorphous substances as wax or asphaltum. " 



Doctor Sherzer also discusses the cause of the richness and variety of coloring 

 of glaciers and glacial lakes. 



In accordance with the rule of the Institution this paper has been referred 

 to a commission consisting of Professor T. C. Chamberlin, of the University 

 of Chicago; Professor Harry F. Reid, of Johns Hopkins University, and Doctor 

 George P. Merrill, of the United States National Museum, and upon their 

 favorable recommendation is published in the series of "Smithsonian Contribu- 

 tions to Knowledge." 



RICHARD RATH BUN, 



Acting Secretary. 



SMITHSONIAN INSTITUTION, 



WASHINGTON, D. C., January, 1907. 



