CONTENTS 



CHAPTER XXIII 



CALCAREOUS FORMATIONS, VOLCANIC MUDS, PALAGONITE-TUFFS 



General Character, 317. — Coral Limestones, 318. — Foraminiferal Limestones, 

 319.— Pteropod-oozes, 320. — Foraminiferous Volcanic Muds, 321. — Samples 

 322. — Altered kinds, 324. — Submarine Palagonite-tuffs of mixed composi- 

 tion, 326. — Samples, 330. — Altered Basic Tuffs, 332. — Submarine Basic 

 Pumice Tuffs, 333. — " Crush-tuffs " formed of basic glass and palagonite, 

 334. — Zeolitic Palagonite-Tuffs, 334. — Palagonite-marls, 335. — Acid Pumice 

 Tuffs, 336 Pages iiT— lid 



CHAPTER XXIV 



PALAGONITE 



Its abundance in a fragmental condition in Vanua Levu, 337. — Its occurrence in 

 deep-sea deposits, 338. — Modes of formation in situ,' 338. — In the 

 upper portion of a basaltic flow, 339. — In the groundmass of hemi-crystal- 

 line basaltic rocks, 339. — In veins in a basic tuff-agglomerate, 340. — In the 

 fissures of a basaltic dyke, 341. — In the matrix of pitch-stone agglomerates, 

 349. — In ''crush-tuffs," 341. — Regarded as a solidified magma-residuum of 

 low fusibility, 342. — Its connection with crushing, 342. — Bunsen's experi- 

 ment, 343. — Rosenbusch and Renard, 344. — The Nandua series of beds, 

 345. — Suggested explanation of the origin of palagonite, 346. — Type of 

 basalt associated with palagonite, 347. — Hydration and disintegration of 

 palagonite, 348 Pages 337—349 



CHAPTER XXV 



SILICIFIED CORALS, FLINTS, LIMONITE 



Mode of occurrence of the silicified corals, 351. — Their character and structure, 

 352. — Flints, nodules of Chalcedony, Agates, etc., 353. — Other siliceous 

 concretions, 354. — Jasper, 355. — Deposits of Limonite, 356. — Magnetic 

 Iron-sand, 357. — Suggested explanation of the silicification of the corals 

 358. — Note on a silicified Tree-fern, 360 Pages 350—360 



CHAPTER XXVI 



MAGNETIC ROCKS 



Previous observations, 361. — Magnetic Polarity usually caused by atmospheric 

 electricity, 362. — Displayed by both acid and basic rocks, 364. — Very 

 frequent in Vanua Levu, 365. — Its relation to specific weight, 366. — The 

 influence of locality, 367. — Frequently observed in mountain peaks, 367. — 

 Description of the peaks, 368. — Measurement of the polarity of rocks, 370. 



Pages 361 — 371 



