CHAPTER VI.. The Work of the Ocean.

THE WORK OF THE OCEAN.

Volume and composition, 324. Topography of bed, 326. Distribution of marine life, 328.

+Processes in Operation in the Sea+ 329 Diastrophism, 329. Vulcanism, 332. Gradation, 333.

+Movements of the Sea-water+ 334 Differences in density and their results, 335. Differences in level and their results. 335. Movements generated by winds, 336. Movements generated by attraction, 322. Aperiodic movements, 338. Summary, 339.

+Waves+ 339 Wave-motion, 339.

+Work of the Waves+ 342 Erosion 342 By waves and undertow, 342. Topographic Features Developed by Wave Erosion 349 The sea-cliff, 349. Chimney rocks, etc., 350. Sea caves, 350. The wave-cut terrace, 351. Wave erosion and horizontal configuration, 353. Transportation by Waves 354 Deposition by Waves, Undertow, and Shore Currents 355 The beach, 355. The barrier, 356. The spit, the bar, and the loop, 357. Wave-built terraces, 363. Effect of Shore Deposition on Coastal Configuration 363

+Summary of Coastal Irregularities+ 364

+The Work of Ocean-currents+ 366

+Deposits of the Ocean-bed+ 368 Shallow-water Deposits 369 Littoral deposits, 369. Non-littoral, mechanical deposits in shallow water, 369. Characteristics of shallow-water deposits, 373. Topography of shallow-water deposits, 374. Chemical and organic deposits, 375. Limestone, 378. Deep-sea Deposits 378 Contrasted with shallow-water deposits, 378. Sources, 380. Mechanical inorganic deposits, 380. Organic constituents of pelagic deposits, 382. Chemical deposits, 383.

+Lakes+ 386

Changes taking place in lakes, 387. Lacustrine deposits, 388. Extinct lakes, 388. Lake ice, 389. Saline lakes, 391. Indirect effects of lakes, 392. Composition of lake waters, 392.