OBEX. 



[The Fossils, the names of which are printed in Italics, arejiguredin the volmne.] 



Abioh, M., on trachytic rocks, 467. 



Acrodus noMlis, tooth of, 321. 



Acrolepis Sedgwiekii, scale of, 854. 



Actceon acutus, great oolite, 308. 



Actinolite-schist, 590. 



jEchmodus, scales and outline of, 321. 



jEgean Sea, mud of, 35. 



. . . ., animal life in depths of, 136. 



iEpiornis of Madagascar, 348. 



Agglomerate, volcanic rock, 471, 472. 



Agnostux integer, A. rex, 450. 



Agassiz, M, cited, 87, 217, 321, 349, 396, 415, 418. 



.., on fossil fishes of molasse and faluns, 170. 



. ., on fossil fish of lias, 320. 



. ., on fossil fish in Permian marl-slate, 353. 



. ., on fish from Sheppey, 217. 



. ., on footprints, 348. 



. ., on fishes of brown-coal, 540. 



.., on glaciers, 146, 149. 

 Age, test of, by fragments of older rock, 101. 



. . of metamorphic rocks, 611. 



.., test of, in plutonic rocks, 573. 



.., of Spanish volcanoes, 536. 



. ., of volcanic rocks, how tested, 519, 522. 

 Air-breathers in coal, rarity of, 401. 

 Aix-la-Chapelle, hot springs at, 573. 

 Alabama, cretaceous shingle of, 255. 

 Alabaster defined, 13. 

 Alberti on the Keuper, 333. 

 Alexander, Capt, marine sheila in crag found 



by, 155. 

 Alluvium, term explained, 79. 

 . . . ., formation of, 81. 

 .... in Auvergne, 80. 

 Alpine blocks on the Jura, 148. 

 .... erratics, 146. 

 Alps, curved strata of, 58. 

 ...., elevated fossiliferous rocks in, 4. 

 . . . ., nummulitic formation of, 230. 



, of Switzerland, 613. 



, Swiss and Savoy, cleavage of, 601. 



Altered rocks, 479. 



.... by subterranean gases, 595. 



Alternations of rocks, 14. 



.... of marine and freshwater formations, 32. 



Alum-schists, Silurian, of Sweden, 451. 



Alumine in rocks, 11. 



Amblyrhynchus cristatus (recent) 325. 



America, North, Lithodomi in beaches of, 78. 



...., South, cretaceous strata, 255. 



, South, fossils of, 163. 



. . . ., South, gradual rise of parts of, 46. 

 Ammonites bi/rons, A. Nodotianus, t, A. stri- 



atulus, A. Walcottii, 319 ; A. Braiken- 



ridgii, A. margaritatus, A. Stokesii, A. 



striatulus, 316; A. Elizabethan, A. Jason, 



804 ; A. Humphresianus, 315 ; A. Rhotoma- 



gensis, 251. 

 Ampelite, or aluminous slate, 590. 

 Amphibole, 465. 



A.mphibolite, or hornblendo rock, 472, 590. 

 Amphistegina Ilauerina, eocene, 179. 



Amphitherium Broderipii, jaw of, 311. 



.... Prevostii, jaw of, 311. 



Ampullaria glauca (recent), 30. 



Amsterdam, or St Paul Island, 508. 



Amygdaloid, 468. 



Ananchytes ovakis, chalk, 243. 



Ancillaria subulata, eocene, 31. 



Ancyloceras gigas, 258 ; A. spinigerum, 251. 



Ancylus elegans, pleistocene, 29. 



Andolys, chalk-cliffs at, 268. 



Andernach, strata near, 540. 



Andes, plutonic rocks of, 577. 



. . . ., rocks drifted from, to Chiloe, 150. 



Andesite, 467. 



Anodonta Cordierii, A. latimarginatus (re- 

 cent), 28. 



Anoplotherium commune, tooth of, 210. 



.... gracile, outline of, 225. 



Anthophyllum lineatum, 182. 



Antholithes, coal, 371. 



Anthracite in Ehode Island, 597. 



Anticlinal line, 48, 57. 



Antrim basalt, age of, 180. ' 



. . . ., rocks altered by dikes in, 480. 



Antwerp, strata like Suffolk crag near, 173. 



Apateon pedestris, a carboniferous reptile, 396. 



Aphanite, or cornean, 472. 



Apennines, limestone in, 478. 



Appalachian coal-field, 389. 



Appalachians, altered rocks in, 596. 



Apiocrinites rotundus, oolite, 306. 



Aptychus latus, oolite, 302. 



Apteryx in New Zealand, 164. 



Apus t dubius, coal, 3S5. 



Aqueous rocks defined, 2. 



.... rocks, mineral character of, 97. 



deposits, superposition of, 96. 



Aralo-Caspian formations, 175. 



Arbroath paving-stone, 415. 



...., section from, to the Grampians, 48. 



Archegosaurus medius, skin of, A. minor, 

 coal-measures, 397. 



Archiac, M. d', cited, 149. 



. . . ., on fossils in chalk, 251. 



. . . ., on shells in French lower eocene, 22S. 



ArdSche, lava in, 484. 



Arenaceous rocks described, 11. 



Argillaceous rocks, 11. 



.... schist, 589. 



Argile plastique, or lower eocene, 229. 



Argyleshire, trap-vein in cliff, 477. 



Argyll, Duke of, on Isle of Mull tertiaries, 179. 



Arkose, 590. 



Arran, age of granite in, 583. 



...., section of, 585. 



Arran, dike of greenstone in, 477. 



Arrangement of fossils in strata, 5, 21. 



Arthur's Seat, altered strata of, 481. 



Arvicola, tooth of, 167. 



Asap7M8 tyrannus, lower Silurian, 440. 



Aspiduraloricata, Permian, 334» 



Astarte bipartita, A. Omalii, 171. 



