INDEX. 



339 



Rocky Mountains, volcanoes in, in Eocene, 283 

 Roemer, on Lower Cretacic climate, 282 

 Rogers, T., cited, 239 



On glacial deposits of Africa, 290 

 Rogers and Schwarz, on glacial deposits of Africa, 2'Jl 

 Romero, cited, 96 

 Rooms, size of, at Gran Quivira, 86 



in ruins, 77, 83 

 Ross, R., cited, 181, 220 

 Roxbury, formation, 267 

 Ruins, abandonment of, 82 



abundance of, in Arizona, New Mexico, etc., 47 



age of, 73 



factors determining location, 80 



in Guatemala Highlands, 218 

 northwestern New Mexico, 75 B. 



location of, in respect to agricultural lands, 48 



nature of, in Arizona, 47 ff . 



near Mexico City, 97 fl. 



of southern Arizona, 47 ff. 

 the Mayas, 175 

 Yucatan, 183 ff. 



orientation of, 59 



relation to terraces, 44 

 Ruelas. S , 54 

 Russell, F., cited, 37, 48, 50, 51, 69 



Sabino Canyon, ruins at, 52 



Sacaton grass, 72 



Sage brush, 21 



San Andreas Mountains, 38 



San Diego rainfall compared with sim-spots, 120 



San Francisco, California, rainfall of, 159 



Compared with sun-spots, 119 f. 

 San Francisco, Sonora, ruins of, 66 

 Sand dunes at Disemboque, 66 



relation to agriculture in dry regions, 81 

 Mountains, 102 

 Sanger, rainfall of, 158 

 San Juan Teotihuacan culture, 97 ff. 

 San Miguel Amantula, excavations at, 97 

 San Pedro Valley, terraces of, 26 

 San Xavier Indian Reservation, erosion at, 33 



ruins at, 51 

 Santa Barbara, rainfall of, 159 

 Catalina Mountains, 17 

 Rainfall of, 12 

 Terraces of, 25, 29 

 Cruz Mountains, 284 



Reservoir Company, 58 

 River, length of, 50 

 terraces of, 31 

 recent terraces of, 33 

 station, 58 

 Valley, drainage of, 54 



former density of population, 50 ff. 

 present population of, 50 

 terraces of, 24, 29 

 Lucia, 218 

 Rita Mountains, dry farming among, 60 



terraces of, 25 

 Toma River, terraces of, 213 

 Satan's Canyon, 76 f. 

 Savannas, cause of, 216 

 Sawtooth Mountains, 18, 58 

 Sayal, ruins, 229 



School of American Archeology, 44, 83 

 Scotland, Proterozoic glaciation in, 272 

 Schuchert, Chas., cited, 5, 251, 255 ff. 



Contribution by, 265 ff. 

 Sea shells among ruins, 67 



Seasonal distribution of rainfall, effect on tree growth, 164 

 Sediments, climatic evidence of, 273 

 Seibal, location of, 217 



ruins of, 229 

 Seler, cited, 227 



Sequoia sempcrvirens: 



Curve of growth, 133 



Formula of relation of growth to rainfall, IGfi 

 Habitat of, 141 

 Sequoia washingtoniana, 141 ff., 142 f. 

 Age of measured trees, 146 

 Corrective factors, 144 ff. 

 Curve of growth, 133 

 Curves of annual growth compared with rainfall, 



161 ff. 

 Dimensions vs. appearance of, 142 

 Distribution of, 132 



Young trees, 153 

 Double rings in, 146 

 Durability of wood of, 143 

 Dying out of species, 153 

 Habitat of, 141 

 Habits of growth, 151 

 Importance of curve of growth, 141 ff. 

 Interpretation of curve of growth, 157 

 Number of measurements, 143 f. 

 Rate of growth in old age, 151 

 Relation of growth to season of precipitation, 151 

 Seve series, 270 



Shading, effect upon tree growth, 134 f. 

 Shakayuma (see Charco del Yuma), 54 ff. 

 Sharks, distribution of, in Paleozoic, 277, 278 

 Shell heaps at Disemboque, 67 

 Shift of the storm track, 193 

 Shifting of cUmatic zones, 174 

 Shortleaf pine, corrective factors of, 132 



curve of growth, 133 

 Shreve, F., cited, 73 

 Sierra Blanco Mountains, 37 

 Nevada uplift, 281 



rainfall of, 157 f. 

 Sierrita Mountains, 17 

 Siluric: 



Aridity in, 277 

 Climate, 258, 276, 277, 286 

 Life of, 276 



Mountain-making in, 277, 287 

 Reef corals in, 276 

 Volcanoes in, 287 

 Sisal (see Henequen), 182 

 Smith, on Triassic chmate, 280 

 Smith's Lake, 76 

 Snow-fall, effect upon tree growth, 132 



in polar regions, Hobbs's theory of, 20G 

 Soil, poverty of, in tropical forests, 222 



relation of depth to climate, 18 

 Solar and terrestrial temperature, 241 ff. 

 constant, 246 



heat, inequality of distribution to earth, 249 

 hypothesis of climatic change, 233 



summary, 251 

 objections to, 241 ff. 

 radiation, effect of volcanoes on, 250 ff. 

 measiu'ed variations of, 236 

 variabiUty of, 274, 275, 289 

 Sonora, climate of, 9 ff. 

 ruins of, 65 ff. 

 terraces in, 100 

 Spaniards, as immigrants in Mexico, 180 



contrast of civilization with that of Mayas, 222 

 effect of intermixture with Indians, 180 



rainfall on occupation of America, 138 

 in Yucatan, 180 

 Spanish Mission, Buzani, 65, 86 



at Gran Quivira, 85 

 Sparagmite formation, 270 

 Spinden, H. J., cited, 215, 227 



Spring droughts, effect upon size of rains in Arizona, 111 

 Springs, ancient, 72, 80, 91 

 Spruce, curve of growth, 133 

 Stages of culture in New Mexico, 75 ff., 82 ff., 84 



