Sedimentary Rocks:
made of sediment (small solid pieces of rock and living things)
sediment is produced by erosion ( running water and wind loosen and carry away rock fragments)
sediment eventually settles out of the wind and water (deposition)
sediment presses together (compaction)
sediment becomes glued together minerals that crystalize in the sediment (cementation) 
3 Major Groups of Sedimentary Rocks
Clastic - formed when fragments are squeezed together (shale, sandstone, conglomerate, breccia)
Organic - formed from animal and plant remains (coal, limestone)
Chemical - formed when minerals that are dissolved in a solution crystalize (limestone, halite, gypsum)