Limestone is a kind of rock that is formed in layers, very slowly over thousands of years. The skeletons of animals and the remains of plants that get trapped in one of these layers are changed into fossils. Scientists can tell when and where different creatures lived by examining fossils.
How did rocks from the bottom of the sea get to the top of our tallest mountain? More than 60 million years ago, India was pushed up against the continent of Asia. This happened because of movements in the huge plates of the earth's crust. Before this, India and Asia were completely separate.
The mountains of the world have been formed in different ways. The Himalayas to the north of India, and the Alps to the north of Italy, were formed when plates in the earth's crust were pushed together. When rocks buckle up, or fold in this way, we call them fold mountains.
Another type of mountain is formed when movements of the plates inside the earth's crust create weak areas, or faults, in the crust. As the plates press together, the mantle pushes its way upwards and cracks appear. The land between the cracks is forced up in a block-like shape. This type of mountain is called a block mountain. The Sierra Nevada in the western United States and the mountain ranges of East Africa are examples of block mountains.
Social Plugin