Ice Ages, theories as to their origin, 20; the three union stations of the ice trains, 27; how the glaciers put the Missouri River together, 29; how they pushed the Mississippi about, 30; how they turned rivers around and made waterfalls for New England, 31; how they chiselled out stone bowls for the Great Lakes, 34; how they made other lakes, 194; the thousand-year clock at Niagara Falls and what it tells about the Ice Age, 35; how the glaciers set Niagara Falls up in business, 36; Muir's eloquent tribute to the marvellous "busy work" of the snowflakes, 37; how the Ice Age glaciers went off and left the butterflies and the flowers in the Alps, 47; how the butterflies missed the train, 48; how Agassiz discovered the Ice Age, 52; how the glaciers moved the hills about, 117; travels of the boulders and how the glaciers rounded them, 146, 155; why there are no big caves in glaciated regions, 148; relation of the Ice Ages to the Dead Sea and the Sea of Galilee, 206; Burroughs's theory as to future Ice Ages, 219; what rain-drop autographs tell of the Ice Age, 246; a perched boulder and its autograph in a New York City park, 250; records of the Ice Age glaciers compared with Cæsar's Commentaries-- curious similarities, 252 Icebergs, how to make them in the schoolroom, 32; how the icebergs of the Ice Age gave the boulders a ride, 153 Ice wells, huge ice water tanks that the Ice Age glaciers left, 49 Indian Ocean, why its waves rise to salute the Himalayas, 140 Islands, oceanic, the tops of volcanoes, 133; islands on the Maine coast and how they were made, 212; how the sea helps the corals build their islands, 225 "Joints," places where rocks don't join, how made, 33; how they help make "perched rocks," 60; joints in the "Marble Rocks" at Jabalpur, 105; joints and the work of the sea's rock mills, 216; use of joints in Nature's stone architecture, 228 Jordan River, why it was born partly grown, 73: why the making of the Jordan Valley was the death of the Dead Sea, 206 Jungfrau, summer pastures on, 41; its beauty, 44 Jupiter, how as rain god he put out the world, 3; place of the planet in the Solar system, 6 Keewatin, one of the central stations of the Ice Age, 28 Kentucky, the sink holes in the cave regions, 200 Kepler and the discovery that there are worlds of worlds, 4 Kettle lakes, how the glaciers of the Ice Age made them, 196 Labrador, one of the central stations of the Ice Age, 28; how the butterflies of Labrador tell that their ancestors missed the train, 49