still thin, and its internal heat makes a tropical climate everywhere,
unchecked by winter's cold, thus forcing plants to a most luxurious
growth.

Descend, and let us wander through this forest and examine it more
closely. What strange trees are here! No oaks, no elms, or ash, or
chestnut--no trees that we ever saw before. It looks as if the plants of
a boggy meadow had shot up in a single night to a height of 60 or 70
feet, and we were walking among the stalks--a gigantic meadow of ferns,
reeds, grasses, and club-mosses. A million columns rise, so thick at the
top that they make twilight at mid-day, and their trunks are so close
together we can scarcely edge our way between them, whilst the ground is
carpeted with trailing plants completely interwoven. What strange trees
they are! Beneath us lies an accumulation of vegetable matter more than
200 feet in thickness--the result of the growth and decay of plants in
this swamp for centuries. All things are here favourable for the growth
of vegetation--the great heat of the ground causes water to rise rapidly
in vapour, and this again descends in showers, supplying the plants with
moisture continuously. The air contains a large proportion of carbonic
acid gas, poison to animals but food to plants, which, by means of its
aid, build up their woody structure. Winds at times level these gigantic
plants, for their hold on the earth is feeble, and thus the mass goes on
increasing.

We are now on the edge of a lake abounding with fish, whose bony scales
glitter in the water as they pursue their prey. Lying along the shore
are shells cast up by the waves, and there are also seen the tracks of
some large animals. How like the impression of a man's hand some of
these tracks are! The hind-feet are evidently much larger than the
fore-feet. There is the frog-like animal which made them, and what a