Index, 



633 



CORDILLERA 



Cordillera, fossils of, 491, 512, 547, 

 550, 560, 578 



— elevation of, 472, 501, 528, 531, 

 571, 576, 589, 593, 602 



— eypseous formations of, 485, 

 489, 504, 509, 536, 543, 552, 

 557, 577 



— clay stone-porphyries of, 471 



— andesitic rocks of, 478 



— volcanos of, 480, 591, 601 

 Coste, M., on elevation of Lemus, 



232 

 Coy inlet, tertiary formation of, 



384 

 Crater, great central one at St. 



Helena, 92 



— internal ledges round, and para- 

 pet on, 93 



— segment of, at the Galapagos, 

 123 



Craters, basaltic, small, at St. 

 Jago, 20 



— of tuff at Terceira, 28 



— at Ascension, 41 



— form of, affected by the trade- 

 wind, 41 



— of elevation, 105 



— of tuff at the Galapagos Archi- 

 pelago, 111, 113, 119, 121 



— small, at the Galapagos Archi- 

 pelago, 115 



— their breached state, 127 

 Crassatella Lyellii, 387 

 Cruickshanks, Mr., on elevation 



near Lima, 273 



Crystallisation favoured by space, 

 78 



Crystals of feldspar, gradual for- 

 mation of, at Port Desire, 437 



Cueullcea, 387 



Cumbre, Pass of, in Cordillera, 502 



Cuming, Mr., on habits of the 

 Mesodesma, 244 



— on range of living shells on west 

 coast, 410, 411 



DANA, Mr., on foliated rocks, 

 465 

 — on amygdaloids, 474 

 Dartigues, Mr., on sphasrulites, 71 



DIKES 



Darwin, Mount, 445 

 Daubeny, Dr., on a basin-formed 

 island, 122 



— on fragments in trachyte, 50 

 D'Aubuisson, on the composition 



of obsidian, 70 



— on the lamination of clayslat e, 

 75 



— on hills of phonolite, 98 



— on concretions, 395 



— on foliated rocks, 465 

 Decay, gradual, of upraised shells, 



265, 267, 273 

 Decomposition of granite rocks, 



428 

 De la Beche, Sir H., on magnesia 



in eruptive lime, 14 



— on specific gravity of lime- 

 stones, 57 



— his theoretical researches on 

 geology, 225 



— on the action of salt on calca- 

 reous rocks, 273 



— on bent cleavage-laminas, 457 

 Denudation of coast at St. Helena, 



104 



— on coast of Patagonia, 214, 228, 

 415 



— great powers of , 415 



— of the Portillo range, 495, 500 

 Deposits, saline, 302 

 Despoblado,valley of, 564, 566, 570 

 Detritus, nature of, in Cordillera, 



292 

 Devonshire, bent cleavage in, 457 

 Diana's Peak, St. Helena, 93 

 Dieffenbach, Dr., on the Chatham 



Islands, 160 

 Dikes, truncated on central crateri- 



form ridge of St. Helena, 93 



— at St. Helena; number of; 

 coated by a glossy layer; uni- 

 form thickness of, 87 



— great parallel ones at St.Helena, 

 97 



— remnants of, extending far into 

 sea round St. Helena, 104 



— not observed at Ascension, 105 



— of tuff, 114 



— of trap, in the plutonic series, 

 139 



