THE CARBONIFEROUS PERIOD. 
81 
silence was unbroken by the song of birds 01 the 
hum of insects. We shall find, it is true, when 
we give a glance at the animals of this time, that 
certain insects made their appearance with the 
first terrestrial vegetation ; but they were few in 
number and of a peculiar kind, such as thrive 
now in low, wet lands. 
Upon this follow a number of sketches intro- 
ducing us to the middle periods, where the land 
is higher and more extensive, covered chiefly 
with Pine-forests, beneath which grows a thick 
carpet of underbrush, consisting mostly of 
Grasses, Rushes, and Ferns. Here and there 
one of the gigantic reptiles of the time may be 
seen sunning himself on the shore. One of these 
sketches shows us such a creature hungrily in- 
specting a pool where Crinoids, with their long 
stems, large, closely-coiled Chambered Shells, 
and Bracliiopods, the Oysters and Clams of those 
days, offer him a tempting repast. Here and 
there a Pterodactyl, the curious winged reptile 
of the later middle periods, stretches its long 
neck from the water, and birds also begin to 
make their appearance. 
After these come the Tertiary periods: the 
Eocene first, where the landscape is already 
broken up by hills and mountains, clothed with a 
varied vegetation of comparatively modern char- 
acter. Lily-pads are floating on the stream 
4 * F 
