at this stage of the baking. After it was baked and cooled the skin was wrinkled and folded into little ridges and depressions. The heated vapor had escaped or cooled, and the skin had wrinkled to cover the shrunken surface.

In a similar way to the process of baking an apple the steam and gases inside of our earth, in some far-off time, pressed unevenly against the earth's crust. They pushed it up in places into great swellings. When the gases had escaped or cooled the crust wrinkled into folds. Sometimes great

THE SHASTA REGION OF THE SIERRA NEVADA MTS.

sections of rocks were uplifted and pushed out of position in blocks.

The folds and blocks which have been uplifted by the internal pressure are the

MOUNTAINS our earth.

ledges are in blocks. Trace the folds in the pic

In the pictures under soil you see that rock

tures on this page.

In some sections of our earth the uplifting and folding are still going on. They are so slow that people do not notice them.

In many mountainous regions there are high plains between the mountain ridges. These are plateaus.

SOMETIMES THE ROCKS ARE PRESSED & TWISTED IN ALL DIRECTIONS

Visit mountains near your school, if there are any. Observe what you can in regard to their formation.

the islands of the sea, showing that they have along the western coast of South America

and North America, across Bering Strait into Asia, across Asia, dividing into two branches in the central part. One branch extends down the eastern coast of Af rica, while the other extends westward across Europe to the Atlantic.

Ocean.
the World Ridge.

It is called

Trace this great highland section in the world pictures. (See pages 7, 9.) Tell in what direction it sends the long slope of each grand division; the short slope of each. Tell on which slopes the long rivers descend.

They help to form the great river and lake basins.

The mountains of the Secondary Highlands are flat-topped and rounded, showing that they are very old and have been very greatly worn down. They

SAN FRANCISCO MTS. ARIZONA, WITH MOUNTAIN MEADOW & PINE FOREST

The highest land-forms of the world, which make the world ridge, are called the PRIMARY HIGHLANDS. They form the great slopes of the continents. The mountains of these highlands are high and rugged. The summits of many of their peaks have never been reached by man. Their great height and rugged.

ness tell us

that these

mountains

were

formed

are secondary only in height, as they are older than the Primary Highlands.

The Appalachian Highlands of North America; the Brazilian and Guiana Highlands of South America are good examples of secondary

highlands. Find and trace them.

Mining towns are scattered among the mountains, because in the mountainous regions the metals and minerals of the world are found. Ranches or mountain farms have been opened up; trade centers, even factory towns, have sprung up in or

A MOUNTAIN SYSTEM.

more recently than other highlands of and food as they need. the world.

From the world pictures and maps tell what mountains belong to the Primary Highlands of

the different continents. Trace them.

On the long slope of each continent you find other highlands. These are the Secondary Highlands of the world.

der to supply the people of the mining

towns with

such arti

cles of clothing

Once mountain traveling was danger ous and tiresome; but through the white man's skill and ingenuity in engineering, mining towns have been connected by the trolley lines, mountains have been tunneled and crossed in long loops so as to lessen the slope, chasms have been