Page:Maury's New Elements of Geography, 1907.djvu/16

12

It is very cold at the tops of high mountains, and many of them are always covered with snow.

Some mountains slope down on all sides, but generally mountains extend in long lines with slopes on but two sides. Such a line of mountains is called a range or ridge. When several ranges near each other extend in about the same direction they are called a mountain chain.

There is a wonderful kind of mountain that seems to be on fire inside. It is called a volcano. There is a great hole called the crater at the top of it, and out of the hole red-hot cinders and melted stones are sometimes thrown far upward.

The land which lies between mountains or hills is called a valley.

1. The Sea.—There are a great many interesting things to learn about the sea. First of all, it is never still. It is always rolling and rocking or dashing its waves into foam on the shore. In storms the waves often drive ships on rocks and wreck them. Another movement of the sea causes it to rise and fall slowly twice in a day. These two movements of the sea are known as tides.