Rain, erosion, 23 Rain prints, 181 Recent epoch, 416, 440, 447 Reconcentration of ores, 289 Record, the geological, 291 Red clay, 187 Red River of the North, 67 Red Sea, 221 Red snow, 115 Reefs, coral, 188 Regional intrusions, 272 Reptiles, 367, 383 Rhinoceros, 408 Rhizocarp, 343 Rhode Island, 356 Rhone glacier, 123 Rhyolite, 240 Richmond, Va., 370 Rift valleys, 221 Ripple marks, 180 Rivers, 54 bars, 65 braided channels, 94 deltas, 108 deposition, 62 discharge, 55 erosion, 59 estuaries, 85 flood plains, 93 floods, 54 graded, 74 gradients, 82 load of, 56 mature, 72, 80, 97, 98 meanders, 96 plains, 99 profile of, 73 revived, 85 run-off, 54 structure of deposits, 102 terraces, 96 transportation, 56, 64 waterfalls, 78 young, 67 Roches moutonnées, 134, 418 Rock bench, 156 Hock salt, 12, 357, 371 Rocky Mountains, 375, 399, 437 Ruminants, 412 Saber-tooth tiger, 413 Saguenay River, 90, 201 Sahara, 15, 146, 150 St. Elias Range, 399 St. Peter sandstone, 150 Salamanders, 383 Salina series, 335 Salt, common, 106, 335 Salt lakes, 106 San Francisco Bay, 197 Sand, beach, 163 of deserts, 149 reefs, 165, 167 storms, 145 Sandstone, 6, 7, 186 Sarcoui, 258 Sauropoda, 386 Schist, 283 Schladebach, 277 Scoria, 250, 255 Scorpions, 339, 340, 363 Scotland, 170, 220, 402 Sea, 155 erosion, 156 deposition, 174 transportation, 162 Sea arch, 159 Sea cave, 158 Sea cliff, 156, 157 Sea cucumber, 363 Seals, 414 Sea stacks, 169 Sea urchin, 332, 379 Seaweed, 176 Sedimentary rocks, 8, 9 Selkirk Mountains, 218 Septa, 338 Sequoia, 378 Shale, 8, 9 Sharks, 345, 405 Shasta, Mount, 262, 400 Sheep, 413 Shenandoah valley, 403 Shores of elevation, 167 Shores of depression, 169 Siderite, 63 Sierra Nevada Mountains, 24, 90, 99, 224, 229, 272, 287, 318, 357, 371, 372, 396, 398, 390, 402, 437 Sigillaria, 362, 367 Silica, 6, 178 Silurian period, 316, 334 life of, 338 Sink hole, 46 Slate, 207, 282 Slaty cleavage, 207 Slickensides, 217 Snake River lavas, 400, 401 Snakes, 384, 405 Soil, 19 Solfatara, 260 Solution, 11 Soufriére, 246 South America, 357 South Carolina, 233 South Dakota, 276, 374, 397 Spanish Peaks, 271, 376 Spherulites, 252 Spiders, 363 Spitzbergen, 378 Sponges, 320, 379 Springs, 41 thermal, 50 Stalactite, 48 Stalagmite, 48 Starfishes, 332 Staubbach, 140 Stegosaurus, 387 Stoss side, 134 Stratification, 5, 64, 180 Striæ, glacial, 114, 133, 418 Strike, 203 Strike fault, 225 Stromatopora, 331, 379 Stromboli, 244 Subsidence, 85, 183, 197 Sun cracks, 180 Superior, Lake, 257 Superposition, law of, 293 Susquehanna River, 403 Sutlej River, 209 Sweden, 199 Swine, 412 Switzerland, 28, 427