INDEX. 
Geneva, lake of, advance of the delta of 
the Rhone in, 27 
change which will take place in the 
distribution of sediment when it is filled 
up, 27 
Genoa, height of the tertiary strata above 
the sea at, 165, 166 
* position of the strata— see diagram 
No. 28, 166 
Geological periods, their distinctness may 
arise from our imperfect information, 56 
Gergovia, hill of, alternation of volcanic 
tuff and fresh-water marls in the, 258 
i section of, 259 
intersected by a dike of basalt — see 
wood-cut, No. 60, 259 
Giacomo, St., valley of, described, 84, 85, 
91 
Gillenfeld, description of the Pulvermaar 
of, 197 
Girgenti, section at — see diagram No. 5. 
64 
shells found in the limestone of, 65 
dip of the tertiary strata at, 74 
— list of fossil shells from — Appen- 
dix II., p. 54 
Gironde, tertiary strata of the basin of the, 
206 
Glaciers of Savoy, great quantities of rock 
brought down by the, 149 
Glen Roy, parallel roads of, 131 
Glen Tilt, junction of limestone and gra- 
nite in — see wood-cut No. 88, 356 
Gly, river, tertiary strata in the valley of 
the, 170 
Gneiss, mineral composition of, 365, 367 
■ — passage of, into granite, 367, 372 
was originally deposited from water, 
367 
• whence derived, 373 
Gozzo degli Martiri, dikes intersecting 
limestone at, 69 
1 view of the valley of — see wood-cut 
No, 23, 110 
Grammichele, beds of incoherent yellow 
sand with shells found near, 66 
bones of the mammoth found in 
alluvium at, 151 
Grampians, granite veins of the, 357 
Granada, tertiary strata of, 170 
Granite, junction of limestone and, in Glen 
Tilt— see wood-cut No. 88, 356 
— formed at different periods, 13, 357 
_ passage from trap into, 361 
origin of, 12, 363 
, passage of gneiss into, 367, 372 
■ changes produced by its contact 
with strata of lias and oolite in the Alps, 
371 
Granite veins, their various forms and 
mineral composition — see wood-cuts, 
Nos. 85, 86, 87, and 88, 353, 356, 370 
Gravesend, deep indentations in the chalk 
filled with sand, gravel, &c, near, 282 
Greywacke, 377 
of the Eisel, 194 
age of the rocks termed, 327 
Greenough, Mr., on fossil shells from the 
borders of the Red Sea, 136 
Grifone, Monte, caves containing the re- 
mains of extinct animals in, 141 
Grit, calcareous, and peperino, sections of 
— see diagrams Nos. 9 and 10, 72 
Grooved surface of rocks, how formed, 
147 
Grosoeil, near Nice, tertiary strata found 
at, 135 
Guadaloupe, active volcanos in, 133 
Guidotti, Signor, on the shells of the gyp- 
sum of Monte Cerio, 159 
Gypseous marls containing fish found at 
Castrogiovanni, 63, 67 
Gypsum, and marls, of the Paris basin, 247 
bones of quadrupeds, &c, in, 251 
on the entire absence of marine re- 
mains in the, 252 
of St. Romain on the Allier, 233 
! ■ beds of, interstratified with the sub- 
Apennine marls, 159 
unaltered shells in the, 159 
Gyrogonites, abundant in the fresh-water 
formations of the Paris basin, 250 
Hall, Sir James, his experiments on rocks, 
124 
on the grooved summits of the Cor- 
storphine hills, 147 
Hall, Capt. B., on the parallel roads of 
Coquimboj 131 
on vertical dikes of lava in Madeira, 
134 
on the veins traversing the Table 
Mountain, Cape of Good Hope, 354 
Hamilton, Sir W., his account of the erup- 
tion of Vesuvius in 1779, 122 
Hampshire basin, tertiary formations of the 
18, 280 
• mammiferous remains of the, 280, 281 
on the former continuity of the Lon- 
don and, 283 
Happisborough, diagonal stratification of 
the crag strata near — see wood-cut No. 
32, 174 
Hartz mountains, geological and geogra- 
phical axes of the, 346 
Hastings sands, their composition, 286 
— . anticlinal axis formed by the, 287 
Haute Loire, fresh-water formation of the, 
235 
Headen Hill, section of, 281 
Heat, its influence on the consolidation of 
strata, 334 
Hebrides, age of the volcanic rocks of the, 
336 
