res? If we are walking on a
sea-beach to-day, we do not look for animals that haunt the forests or
roam over the open plains, or for those that live in sheltered valleys
or in inland regions or on mountain-heights. We look for Shells, for
Mussels and Barnacles, for Crabs, for Shrimps, for Marine Worms, for
Star-Fishes and Sea-Urchins, and we may find here and there a fish
stranded on the sand or tangled in the seaweed.

[Illustration]

SOME RECORDS OF THE ROCKS

(FROM A FIRST BOOK IN GEOLOGY.)

BY N.S. SHALER, S.D.[1]

[Footnote 1: Copyright, 1884, by N.S. Shaler.]

[Illustration]

The geologist cannot find his way back in the record of the great
stone book, to the far-off day when life began. The various changes
that come over rocks from the action of heat, of water, and of
pressure, have slowly modified these ancient beds, so that they no
longer preserve the frames of the animals that were buried in them.

These old rocks, which are so changed that we cannot any longer make
sure that any animals lived in them, are called the "archaean," which
is Greek for ancient. They were probably mud and sand and limestone
when first made, but they have been changed to mica schists, gneiss,
granite, marble, and other crystalline rocks. When any rock becomes
crystalline, the fossils dissolve and disappear, as coins lose their
stamp and form when they are melted in the jeweller's gold-pot.

These ancient rocks that lie deepest in the earth are very thick, and
must have taken a great time in building; great continents must have
been worn down by rain and waves in order to supply the waste out of
which they were made. It is tolerably certain that they took as much
time during their making as has been required for all the other times
since they were formed. During the vast ages of this archaean the life
of our earth began to be. We first find many certain evidences of life
in the rocks which lie on top of the archaean rock, and are known as
the Cambriani and Silurian periods. There we have creatures akin to
our corals and crabs and worms, and others that are the distant
kindred of the cuttle-fishes and of our lamp-shells. There were no
backboned animals, that is to say, no land mammals, reptiles, or
fishes at this stage of the earth's history. It is not likely that
there was any land life except of plants and those forms like the
lowest ferns, and probably mosses. Nor is it likely that there were
any large continents a