634 
INDEX. 
PETHEKWYN. 
Petherwyu, Devonian fossils of, 450. 
Petrifaction, process of, 67. 
Petrophiloides Richardsoni, Sheppey, 265. 
Phacoi^s caudatus^ Silurian, 467. 
- latifrons, Devonian, 450. 
Phascolotherium Bucklandi, 348. 
Phasianella Heddingtone7isis, and cast, 66. 
Phillippi, on tertiary shells of Sicily, 205. 
Phillips, Professor, on fossils distorted by 
cleavage, 592. 
-, on ninety fathom dike, 90. 
•-, on Wenlock limestone and shale, 465, 
467. 
-, on Yoredale series, 395. 
-, Mr. J. Arthur, on origin of gold of 
California, 617. 
Phlebopteris contigua^ Inf. Oolite, 350. 
Phlogopite, 499, 501. 
Pholadomya fidicula, Inf. Oolite, 350. 
Phonolite, 506. 
Phorus extensus, London clay, 266. 
Phragmocei'as ventricosum^ Silurian, 463. 
Physa Bristovii, Middle Purbeck, 325. 
- coh(m7iaris, 55. 
-- hypno7’um, 55. 
Piedmont, absence of lakes in, 186. 
Pile dwellings of Switzerland, 148. 
Pilton, groujD of, Devon, 449. 
Pmnvdaria in Atla7itic mud, 288. 
Pinus sylvestris in peat, 147. 
Pisolitic limestone of France, 285. 
Pitchstone, 505. 
Placodus gigas, Muschelkalk, 380. 
Placoids, rare in Old Red Sandstone, 443. 
Plagiaulax Becklesii, jaw aiid molar of, 
327. 
Plagioclastic feldspars, 501. 
Plagiostoma giganteum. Lias, 354. 
- Hoperi, Chalk, 300. 
Planorbis discus, Bembridge, 253. 
- euomphalus, 55, 255. ■ 
Plants of Bovey Tracey, Miocene, 247. 
-, fossil fresh-water, 57. 
-of the Coal, 420. 
-of the Lias, 364. 
-of the Swiss Upper Miocene, 219. 
Plas Newydd, rock altered by dike near, 
515. 
Plastic Clay, Eocene, 267. 
Platanus aceroides, Miocene, 221. 
Platystoma Suessii, Hallstadc, 377. 
Playfair, on amount of subaerial denuda¬ 
tion, 114. 
-on faults, 87. 
Plectrodus mirabilis, Ludlow, 460. 
Plesiosaurus dolichodeirus. Lias, 361. 
Pleurotoma atte7iuata, Bracklesham, 262. 
- exorta. Eocene, 57. 
Pleurotomaria anglica, and cast, 66. 
-- carinata (flammigera), 434. 
-- granulata, Inf. Oolite, 351. 
■- or7%ata. Inf. Oolite, 351. 
Plieninger, Professor, on Triassic mammi- 
fer, 368. 
Pliocene glacial formations, 189-192. 
-Period, 189. 
-plutonic rocks, 565. 
-strata of Sicily, 204. 
-, term defined, 143. 
-volcanic rocks, 529. 
Plombieres, alkaline waters ( f 585. 
Plumbago of Massachusetts, J. 
PTYOnODUG. 
Plutonic and sedimentary formations, dia¬ 
gram of, 567. 
-, origin of the term, 551. 
-rocks, Mesozoic, 570. 
-Recent and Pliocene, 565. 
-•, Miocene and Eocene, 568. 
-, uncertain tests of age of, 564. 
-defined, 31. 
Podocarya Bucklandi, Oolite, 348. 
Polypterus of the Nile, 444. 
Polyzoa and Bryozoa, terms explained, 197. 
Pomel, M., on fossil mammalia of the Li- 
magne, 235. 
Ponzalslands, globiform pitchstone of, 512. 
Porites ptyriforinis, Devonian, 451. 
Porphyritic granite, 556. 
Porphyry, 506. 
Portland, Cycads in dirt-bed of, 331. 
-oolite and sand, 334. 
'•'■Portland screw," a cast of a shell, 335. 
Porto Santo, marine shells in volcanic tuff 
of, 536. 
Post-Pliocene period, climate of the, 161. 
-mammalia, teeth of, 163. 
-., term defined, 145. 
-lakes of Switzerland, 185. 
-volcanic rocks, 524. 
Potamides cmctus, 56. 
Pothocites Granto7iii, coal-measures, 429. 
Potsdam Sandstone, 480,489. 
Pot-stones in the Chalk, 290. 
Pottsville, coal seams of, 400. 
Powrie, Mr., on Cephalaspis beds, 446. 
-, on Parka decipiens, 448. 
Pratt, Mr., on Eocene Isle of Wight mam¬ 
malia, 254. 
Predazzo, altered rocks at, 571. 
Pressure, solidifying rocks, 65. 
Prestwich, Mr., on age of Sables inferieurs, 
276. 
-, on Chillesford beds, 192. 
-, on Coalbrook Dale insects, 405. 
-, on Eocene strata, 267, 269. 
-, on faults in coal - measure of Coal- 
brook Dale, 88. 
-, on shells of London clay, 264. 
-, on thickness of Coralline Crag, 198. 
PrevostjM. Constant, on Paris basin, 270. 
Primary Limestone, 579. 
-rocks, 458. 
-, term defined, 123. 
“Primordial Zone ” of Bohemia, 481, 482. 
Productus horridus, Permian, 388. 
- scAnireticulatus {antiquatus), 434. 
Progressive development indicated by low 
grade of early mammals, 384. 
Proteacese of Aix-la-Chapelle flora, 304. 
-of Lower Molasse, Switzerland, 237. 
-of (Eningen beds, 221. 
Protogine, 578. 
Protosaurus of Thuringia, 390, 464. 
Protrusion of solid granite, 574. 
Provinces of animals and plants, 126. 
Psammodus porosus, 437. 
Pseudocrinites bifasciatus, Silurian, 466. 
Psilophyto7ipr47iceps, Devonian, 455. 
Pteraspis in Lower Ludlow shale, 463. 
Pterichthys, Old Red Sandstone, 445. 
Pterodactyl of Kentish chalk, 297. 
Pterodactylus a7iglicus. Old Red, 447. 
- crassirost7'is, Solenhofen, 337. 
Ptychodus decurre7is, White Chalk, 297. 
