Final answer:
The North American craton, also known as Laurentia, is a continental block that includes most of North America and Greenland. Only a portion of the craton is visible, while the rest is buried under sediment.
Step-by-step explanation:
The North American craton, also known as Laurentia, is a continental block that includes most of North America and Greenland. It has remained intact since the late Proterozoic era.
However, only a portion of the craton is visible, while the rest is buried under sediment. For example, in the Yucatán peninsula, a crater is buried under more than 500 meters of sediment.