108 
INDEX. 
Velay, ancient "alluviums covered by lava 
at different heights in, 262 
Vertical and inclined strata, great line of, 
from the Isle of Wight to Dieppe, 315, 
Vesuvius, dikes of, 121 
channels formed by the flowing of 
lava from, in 1779, 122 
and Sonima, difference in their com- 
position, 120 
Vichy, tertiary oolitic limestone of, 232 
dip of the lacustrine strata at, 233 
Vienna, tertiary formations of, 21, 212 
age of the tertiary strata of, 214 
■- basin, fossil shells of the — see Table, 
Appendix I. 
Vigolano, gypsum interstratified with sub- 
Apennine marls at, 159 
Villasmonde, shells found in limestone at, 65 
list of fossil shells from — Appendix 
II., 54 
Villefranche, bay of, tertiary strata found 
near the, 135 
Vinegar river, sulphuric and muriatic acids, 
and oxide of iron, in the waters of the, 
252 
Virlet, M., on the tertiary strata of the 
Morea, 170 
Viterbo, volcanic tuffs and sub-Apennine 
mails alternating at, 159 
— age of the volcanic rocks of, 183 
Viviani, Professor, on the character of the 
Sicilian flora, 115 
— on the tertiary strata of Genoa, 166 
Vizzini, junction of inclined tuff and hori- 
zontal limestone near — see diagram No. 
8, 70 
■ changes caused by a dike of lava in 
argillaceous strata at, 70 
■ a bed of oysters between two lava- 
currents at, 73 
Volcanic breccias in Auvergne, how 
formed, 259 
Volcanic conglomerates of the Val di Noto, 
73 
now forming on the shores of Catania 
and Ischia, 73 
Volcanic dikes, strata altered by, 70, 3G8 
Volcanic district of Catalonia, superposition 
of rocks in the — see wood-cut No. 47, 
192 
Volcauic lines, modern, not parallel, 349 
Volcanic region of Naples, changes which 
it has undergone during the last 2000 
years, 118 
Volcanic rocks, distinction between sedi- 
mentary and, 10 
relative age of, how determined, 36 
of the Val di Noto, 68 
of Campania, their age, 126 
. of central Prance, 257 
secondary, of many different ages, 
335 
Volcanic rocks, distinction between plu- 
tonic and, 359 
Volcanos, mode of computing the age of, 
sometimes inactive for centuries, 98 
of Olot, in Catalonia, described — 
see Frontispiece, 183 
extinct, of Sardinia, 193 
of the Lower Rhine and the Eifel, 
193 
the result of successive accumula- 
tion, 240 
attempt to divide them into ante- 
diluvian and post-diluvian, 268 
Volhynia, tertiary formations of, 215 
Voltz, M., on the loess of the Rhine, 151 
Von Buch, M., on the Eifel, 201 
on the tertiary formations of Volhynia 
and Podolia, 215 
on the general range of volcanic lines 
over the globe, 349 
Von Dechen, M., on the volcanic district of 
the Lower Rhine, 201 
on the Hartz mountains, 346 
■ his objections to the theory of M. de 
Beaumont, 346, 347 
on the Cornish granite veins — see 
wood-cut No. 87, 355 
Von Oeynhausen, his map of the Eifel dis- 
trict, 193 
on the volcanic district of the Rhine, 
201 
on the granite veins of Cornwall — 
see wood-cut No. 87, 355 6 
Walton, section of shelly crag near — see 
wood-cut No. 31, 174 
■ lamination of sand and loam near — 
see wood-cut No. 34, 175 
Warburton, Mr., on the Bagshot sand, 280 
Watt, Gregory, his experiments on melted 
rocks, 124, 372 
Weald, denudation of the valley of the, 
285 
secondary rocks of the, divisible into 
five groups, 286 
— section of the valley of the — see 
wood-cuts Nos. 63 and 64, 287, 288 
clay, its composition, 286 
gradual rise and degradation of the 
rocks of the, 289 
alluvium of the valley of the, 295 
extent of denudation in the valley of 
the, 303, 313 
Wealden, secondary group, called the, 325 
organic remains of the, 325 
its great extent and thickness, 329j 
how deposited, 329 
Webster, Mr., on the geology of the Isle of 
Wight, 18, 315 
on the tertiary formations of the 
London and Hampshire basins, 278, 280 
