xii ILLUSTRATIONS 
figure page 
92. East wall of Plover Bay, Siberia. 190 
93. Hanging valley, Plover Bay. . 191 
94. Downward limit of crevasses in Muir Glacier. 198 
95. Crevasses and seracs, Muir Glacier..,. 199 
96. Pinnacles on Columbia Glacier. 200 
97. Back of Columbia Glacier. 200 
98. Level tract on Muir Glacier...... 201 
99. Ideal profile and section of a glacier. 201 
100. Ideal section of water-filled crevasses.. 202 
101. Influence of drift on surface character of glacier. 202 
102. Ice sculpture in Russell Fiord. 209 
103. Diagrams illustrating flotation theory of tidal glaciers. 210 
104. Diagrams illustrating non-flotation theory of tidal glaciers... 211 
105. Contact phenomena of glass and mercury. 212 
106. Ideal section of tidal glacier. 215 
