Northern seas during Tertiary age, 37; Gulf Stream during Tertiary times, 38; the origin of a cold period in the northern hemisphere, 38; remarks on Gulf Stream and arctic currents, 39; circulation of arctic waters, 40; arctic channels during ice age, 41; how the weight of glaciers in the northern hemisphere attracts the waters of the southern seas during ice age, 42; Professor Prestwich on the submergence of European lands, 43; the great Atlantic tide rips the head-waters of the Gulf Stream, 44; high sea-level of Atlantic calm region, 45; tropical Atlantic currents, 46; Sargasso Sea, 48; arctic and Gulf Stream currents, 49; Pacific Ocean currents, 50; slow growth of an ice period, 52; reduction of Cape Horn channel, 53; permanence of antarctic glaciers elevated above the snow-line during mild periods, 54. CHAPTER III. SPREAD OF GLACIERS DURING COLD EPOCHS, 54–61 Spread of glaciers in tropical zone, 54; Professor Agassiz on the origin of Galapagos Islands, 55; the bowlders of Hood’s Island and rookery of Albatross, 56; alpine flora of Galapagos and tropical America, 57; Mr. J. Crawford on ancient glaciers in Nicaragua, 58; Cuba and Republic of Colombia during ice age, 58; destruction of animal life during glacial age, 59; temperature of North Atlantic and Mediterranean Sea during ice age, 60; temperature of ocean during warm epochs, 61; generative age ascribed to warm eras; Professor Wright on pre-glacial man, 61. CHAPTER IV. THE GLACIERS OF THE TEMPERATE ZONE, 62–75 Professor Hitchcock on the early history of North America, 62; glacial deposits of Nantucket and Martha’s Vineyard, 63; Professor James Geikie on the glacial deposits of Northern Italy, 64; California coast ranges the work of Sierra glaciers, 65; ancient glaciers on the Pacific slope north of California, 67; Professor Geikie’s views on the ancient glaciers in the Salt Lake region, 68; Colorado Cañon, 69; the conglomerate deposits in the Appalachian district, 69; remarks on the glacial boundaries in United States during ice age, 70; sands of Florida, 71; ancient ice-sheets of the plains west of the Mississippi River, 73; the driftless region of Wisconsin, 74; tropical waters of North Atlantic chilled during ice age, 75; the drifted snow of British America and Siberia during ice age, 75. CHAPTER V. REMARKS ON THEORIES ADVANCED FOR EXPLAINING ICE PERIODS, 76–93