Primates, distribution of, 138, 139 



Eocene, 137 



European, 138 



evolution of, 146 



origin of, 111 



radiation of, 137, 138, 142 

 Proavian, 129, frontispiece 

 Proboscidea, 74, 136 

 Proteins, 84, 85, 99, 100 

 Proterozoic era, 46, 113, 118, 144 



era, climates of, 51, 55 



era, time ratio of, 69 



lavas, 64 



sediments, thickness of, 64, 67 

 Protochordates, 118 

 Protoplasm, 82, 88, 99, 100, 105 



alveolar substance of, 83 



chemical characteristics of, 84 



combinations of elements in, 84 



lability of, 85 



living, evolution of, 107 



physical characteristics of, 83 



variation in, 87 

 Protopterus, 121 

 Protozoa, 96, 97, 113 

 Psychozoic era, 45, 66 

 Pueblo Indians, 152, 154 

 Pulse of life, 81, 109, 111, 144, 146 

 Pumpkins, 154 

 Pyramid Lake, 185 



Rabl, C., 123 



Racial differences, causes of, 148 



Radioactive elements, 42 



minerals, rate of disintegration of, 

 as basis for computing geologic 

 time, 67, 68 

 Radiolaria, 113 

 Rain, 54 



first, on earth, 37 

 Rainfall, 153, 154, 184 

 Ranodon sibericus, 124 

 Recrystallization, 40 

 Redi, F., 90, 91, 92 



INDEX 205 



Reptiles, 65, 73, 81, 132, 145 



Age of, 46 



foot of, 124 



origin of, 65, 111, 125 

 Revolutions, 71 

 Rhinoceroses, 136 

 Rhodesia, 188, 189 

 Rhythms, in solar energy, 109 

 Rice, 179 

 Richter, 96, 98 

 Rivers, 54, 57, 76 

 Rocks, acidic, 49 



basaltic, 49 



basic, 49 



granitic, 49 



sedimentary, 57, 61, 67, 68 



stratified, composition of, 60 

 Rodents, 136 

 Roman history, effect of climate on, 



190 

 Ross, 90 



Sacramento, deaths in, 158, 161 

 Salamander, foot of, 124 

 Salt deposits, 32 



evidence of, for climatic change, 185 



oceanic, derivation of, 32 



oceanic, significance of, 31 

 Salt Lake City, rainfall at, 153 

 San Diego, deaths in, 158, 161 

 San Francisco, deaths in, 158, 161 

 Sandstones, 58, 60, 61, 67, 68 

 Santa Fe, rainfall at, 153 

 Satellites, 6, 19 

 Saturn, 5, 6, 31 

 Sauropoda, 111, 130, 132, 145 



characteristics of, 131 

 Savagery, 152, 154 

 Schafer, E. A., 98 

 Schuchert, C., 110 

 Schwann, 93 

 Scorpions, 90 

 Sea-anemones, 114 



