450 



INDEX. 



Old red sandstone, section of, at the defile of the 



Avon, 245. 



■ of Forest of Dean, 284. 



immense thickness of, in the 



neighbourhood of Mitchel Dean, 284. 

 ' conglomerate of, at Mitchel Dean, 



285. 



— ■^— distinction between it and newer 



red sandstone, clearly seen in Bristol coal-basin, 

 299. 



■ in the environs of Tortworth, 



338. 



341. 



shire, 355. 



conglomerate of, at Tortworth, 



organic remains rare in, 342. 

 • in the north-west of Gloucester- 



in Mendip hills, 360. 



Onega, Lake of, 8. 

 Oolite, 36. 



on the coast of France, 77. 



inferior, extent and position of, in Calva- 



dos, 79. 



fossils of, in Calvados, 80. 



306. 



of south-western coal district of England, 



■ lower, in the environs of Tortworth, 35 1 . 



at Stinchcombe hill, 369, 



Opossum, fossil remains of, in the Stonesfield 



slate, 391. 

 Organic remains : see Fossil organic remains. 

 Ormuz Island, in the Persian Gulf, rocks of, 4 1 1 . 

 Orthocerae of the limestone of St. Joseph's Island, 



in Lake Huron, described, 196, 197. 



of Thessalon Island, 198. 



in transition rocks in the environs of 



Tortworth, 328. 

 in transition limestone of Forest of 



Dean, 283. 

 Oural mountains, 34. 

 Outline masses of oolite and lias in south-western 



coal district of England, 307. 

 Owen, George, of Henllys, author of Essay on 



Pembrokeshire, written in the year 1570, 312. 

 Palates of fish in lias, 43. 

 Paramoudrse in chalk flints in Norfolk, 377. 

 Pargas, parish of, 3. 



Pargasite in primitive limestone, 3. 



Parkes, S. Esq., notice on the black oxide of man- 

 ganese of Warwickshire, 168. 



Pecopteris reticulata, fossil fern, described, 424. 



Penang, island of, 165. 



Pennant grit of Bristol coal measures, 253, 256, 

 258. 



■ the equivalent of, in the Forest of' 



Dean, 287. 



Persian Gulf, account of various islands in, 410 — 

 412. 



shallowness of the upper end of,. 



412. 



Pinite in porphyry of Glen Tilt, 65. 



Plants, fossil, found in the Col de Balme, 162. 



in gypsum of Monte Seano, 170. 



of the iron sand in Sussex, describ- 

 ed, 421. 



Plastic clay, arenaceous limestone of, 52. 



~— sand of, at Chuton Bunny, near Mud- 



diford, Hants, 93. 



Plesiosaurus, 43. 



head of, described, 119. 



dentition and lower jaw of, 120. 



upper jaw of, 121. 



analogies of the, 120, 122. 



vertebrae, apparently belonging to, 



found in the Kimmeridge clay, 1 23. 

 bones of, found in the lias of Twiver- 



ton and Keynsham, 302. 



■ — in oolite, at Stinchcombe hill, 352. 

 on the discovery of an almost per- 



fect skeleton of, at Lyme Regis, 38 1 . 



dolichodeirus, extraordinary length 



of the neck of, 382,389. 

 proportional smallness of the head of. 



382. 



vertebrae of, 382. 



compared to the tortoise, 383. 



humero-sternal parts of, 386. 



extremities of, 387. 



resembles the turtle in its motion. 



388. 



probable habits of the, 389. 



Pleta district, 10. 



Polior Island in the Persian Gulf, 412. 



Porphyritic conglomerate in France, 83. 



