| A | B |
|---|
| sedimentary rocks | made from sediments |
| clastic sedimentary rocks | made from pieces of other rocks that are either cemented or compacted together |
| chemical sedimentary rocks | rocks are formed from minerals dissolved in water |
| organic rocks | formed from the remains of plants and animals |
| stratification | occurs when visible layers are formed by changes in the type of sediments deposited |
| fossils | reamins or traces of plants and animals preserved in sedimentary rock |
| geodes | hollow spores in rocks often that are filled with mineral crystals |
| graded bedding | occurs when heaviest sediments are deposited on the bottom by fast moving water, lightest sediments on top deposited as the moving water slows down |
| pumice | rock that is full of holes; floats on water |
| scoria | rock that is full of holes; does not float on water |
| obsidian | glassy rock; known as volcanic glass |
