James Hutton, who lived in Scotland during the 18th century, made three great discoveries that geologists use to read geologic history. They are 1) the present is the key to the past, 2) the earth is much older than people thought, and 3) rocks can form from cooling magma. We will use his and other discoveries to read the geologic story of the Park. We will examine common rocks and minerals to see how they form deep in the Earth’s crust, discuss the tectonic forces that brought them to the surface, and observe the weathering processes that recycle them back into the Earth. Learn how mountains form, how old they might be, and what went before. Discussion topics include geologic time, radiometric dating, plate tectonics and Earth history.