Not only does sediment spread horizontality and from youngest (top) to oldest (bottom), it also continues to spread flat in all directions until it either runs out of material—pinches off—or hits a barrier. this is known as the
law of original horizontality
law of superposition
law of original lateral continuity
law of gravity and oppositional force
law of cross-cutting relationships

Match your vocabulary word to its definition. 1. emigration 2. immigration 3. migration 4. overpopulation 5. sustainable development 6. under population 7. unsustainable development 8. urbanization the movement from one place to another the number of people exceeds the available natural resources in an area leaving one's homeland to settle in a new place the increase in the population of a city the movement of people to a new country the ability to meet current needs without reducing the ability to meet future needs resources being used up at a faster rate than they can be replenished birth rate insufficient to replace the existing population