APPENDIX. 761 



of occurrence of salt. — 249. Absence of fossils. — Geography and. origin of 

 the salt in the beds. — 251. Absence of land-plants. — Cause of extinction of the 

 life of the Niagara Period. — Sixth Period of the Silurian, or third of the Upper 

 Silurian. — General conditions. — Kinds and distribution of rocks, contrasting the 

 Interior and Appalachian regions. — 253. Abundance of life. — Prominent kinds 

 of animal life. — 255. Geography; contrast with the Salina Period. — -256. Gene- 

 ral features of the Upper Silurian. — 257. Conditions of the continent. — Con- 

 trast between the Interior and Appalachian regions. — 25S. General features of 

 the life. — Radiates. — Mollusks. — 259. Articulates. — Evidence as to climate. — 

 260. Distribution of the Upper Silurian. — Formations in foreign countries. — 

 262, 263. General features .of the life. — 264.. Fishes. — Their appearance in the 

 Silurian, if true, in harmony with a general law in history. — 265. General con- 

 clusions. 



XII. Devonian Age. — Page 265. Origin of the name Devonian. — Transition 

 between Silurian and Devonian. — The five Periods in the American Devonian. — 

 Lower and Upper Devonian ; distinction in rocks. — 266. First Period of the 

 Devonian. — Kinds and distribution of rocks. — Plants. — 267. Common Mollusks. 

 — 268. Geographical conclusions. — Region of Appalachian subsidence not em- 

 bracing the Green Mountain region. — 269. Second Period of the Devonian. — 

 Three Epochs. — Kinds of rocks, and their distribution. — 270. Plants; Proto- 

 phytes. — 272. Characteristic animal life. — Extent of coral-reefs. — The first of 

 Vertebrates. — Sub-kingdoms represented. — New genus of Brachiopods. — Animal 

 remains in hornstone. — 275, 276. — Remains of Fishes. — The two grand divi- 

 sions represented, and their characteristics. — The grand division not repre- 

 sented. — The kind of Selachians in the early Devonian. — The kinds of Ganoids. 

 — Characteristic of the tails of the ancient fishes. — 278. Geography. 



XIII. Devonian Age, Concluded. — Page 280. Third Period of the Devo- 

 nian. — The three Epochs. — 281. Distribution of the Hamilton formation. — 282. The 

 earliest land-plants ; their kinds and relations to modern plants. — 284. Gonia- 

 tites. — 286. Geographical conclusions. — 287. Life. — Fourth Period of the De- 

 vonian. — The two Epochs. — Kinds and distribution of rocks. — 289. Life. — 290. 

 Geographical conclusions. — 291. Life. — Fifth Period of the Devonian. — Kinds 

 and distribution of rocks. — 293. Geographical conclusions. — 294. Foreign De- 

 vonian ; what called in Scotland. — 295. Plants. — Animals. — 299. General Geo- 

 graphical features of America. — 300. Condition of the region of the Rocky 

 Mountains and Apj>alachians. — Condition as to rivers. — Origin of rocks. — 301. 

 Geographical changes. — Geographical condition of Europe. — Two great steps 

 of progress in the life of the world. — 302. Groups to which the land-plants 

 belong, and the relations of the earliest Flora to these groups. — Reptilian feature 

 of Ganoids, and conclusion therefrom as to the commencement of the type of 

 fishes. — 303. Changes in the life of the world during the Devonian Age. — 304. 

 Disturbances closing the Age. 



XIY. Carboniferous Age. — Page 305. The three Periods; succession of 

 phases. — Principal areas in North America. — 306. First Period. — Contrast be- 

 tween the Interior and Appalachian regions in rocks. — 310. Prominent features 

 of the animal life. — Classes of Vertebrates represented. — The first American 

 Reptiles, and the conditions under which the tracks were formed. — 316. Geo- 

 graphy of North America. — 318. Resemblance of American and Foreign Sub- 



