Index 



Sharks, spines, 107* 



teeth, 105, 106,* 108,* 234 * 

 Shastasaurus, 138. 

 Sigillaria, 122, 142. 

 Silurian period, 75. 

 Smilodon, 257,* 258. 

 Snakes, Eocene, 235. 

 Sphargis, 198, 200.* 

 Spines of sharks, 107,* 108. 



their significance, 75. 



of Stegosaurus, 170, 171. 



of trilobites, 75. 

 Sponges, 50. 

 Squid, 42, 43.* 



Stegocephala, 118, 119, 124, 125. 

 Stegosaurs, 170,*]71. 

 Stylacodon, 190. 

 Sunfish, 102.* 



Tapir, 256. 



Teeth of anomodonts, 128. 



aye-aye, 189. 



birds, 180, 181,* 182. 



dinosaurs, 164, 169, 206,* 209. 



elotheres, 242. 



mammoth, 248, 263.* 



mastodon, 263,* 266. 



multituberculata, 188-190. 



platypus, 188. 



polyprotodonts, 190. 



reptiles, 128. 



sharks, 105,* 106,* 108,* 234.* 



saber-toothed cats, 244, 257.* 



Titanotheres, 239. 



Zeuglodon, 234. 

 Theriodontia, 128. 

 Theromorpha, 128. 

 Theropoda, 148, 164, 165,* 166.* 

 Thespesius, 204-206. 



Thespesius, skull, 149,* 205. 



teeth, 206.* 

 Time, geological, 56. 



standards of, 56. 

 Titanichthys, 99. 

 Titanotheres, 237,* 238, 239. 

 Tortoise, age of, 159. 

 Tracks, 13, 14, 15, 113-116. 



in Connecticut Valley, 15, 16. 



of amphibians, 115.* 



of dinosaurs, 139.* 



of reptiles, 115.* 

 Triassic life, 1. 



dinosaurs, 139. 



mammals, 185-187. 

 Triceratops, 208. 

 Triconodon, 189.* 

 Trilobites, 45, 64,* 67.* 



legs, 65, 66.* 



tracks, 14. 

 Tunicata, 38. 

 Turtles first, 141. 



Cretaceous, 198-200. 



Jurassic, 176. 

 Tusks of mammoth, 248. 



of mastodon, 246, 247. 



rarely found, 10, 



Uintatherium, 228,* 229, 230. 

 Undina, 103.* 



Vermes, 47. 



Vertebrates, earliest, 73, 85. 



White River beds, 236. 



Xiphactinus, 196. 



Zeuglodon, 235. 



(1) 



291 



