of, 57-61;
outer, 78;
table of relative masses of sun and, 77.

Plant life in the Sargassum basins, 156.

Plants and animals,
protection of,
by mechanical contrivances, 364;
and trees, work of the roots of, on the soil, 316, 317;
water-loving, 181;
forming climbing bogs, 332.

Polar axes, nodding movement of, 54.

Polar snow cap, 66.

Polyps, 155, 353.

Pools, circular, 203.

Prairies, 340, 342.

Radiation of heat, 159.

Rain, 152, 156, 164, 168, 170, 328, 330;
circuit of the, 156-168;
drops, force of, 169, 170;
spheroidal form of, 170;
electrical action in the formation of snow and, 164;
work of the, 171.

Realm, unseen solar, 75.

Reeds, 332.

Religion,
conflict between science and, 20, 22;
struggle between paganism and, 21.

Rivers and _debris_, 183;
changes in the course of, in alluvial plain, 182;
deposition of, accelerated by tree-planting, 181;
great, always clear, 205;
inundation of the Mississippi, eating away land, 182;
muds, 222;
newly formed, cutting a canon, 195;
of snow-ice, 211;
origin of a normal, 173;
oxbow of a, 182,183;
sinking of, 199;
swinging movement of, 179-181;
river-valleys, 193, 194;
diversity in the form of 188-191.

Rocks, 145;
accidents from falling, 174;
cut away by sandstones, 188;
divided by crevices, 252;
duration of events recorded in, 389, 390,
ejection of, material, 311;
falling of, 174-176;
formation of, 262, 263;
from the present day to the strata of the Laurentian, 390;
migration of, 291;
poised, indicating a long exemption from strong earthquakes, 388;
rents in, 252, 253;
stratification of, 349, 350, 352, 365, 390;
testimony of the, in regard to glaciers, 228;
under volcanoes, 303;
variable elasticity of, 366;
vibration of, 367, 368;
rock-waste, march of the, 343;
water, 250, 267.

Rotation of the earth affected by tides, 130;
of the planetary spheres on their axes, 56.

Salicified forests, 124.

Salt deposits formed in lagoons, 200;
found in lakes, 199-200.

Sand bars, 183;
endurance of, against the waves, 145;
hills, travelling of, 123;
marching, 123;