as causing migration and extinction, [122]

causes of, [125]

the essentials to the production of, [136]

probable date of the, [160]

and the climax of continental development, [206]

date of last, [233]

Glacial phenomena in North America, [116]

Glaciation was greatest where rainfall is now greatest, [139]

action of meteorological causes on, [142]

summary of chief causes of, [144]