Mudstone, shale, and limestone are examples of sedimentary rock likely to contain fossils. As the layers of sediment build up on top of one another, they create a physical timeline. The oldest layers, ...

Chalk, limestone, shale, and sandstone are all examples of sedimentary rocks. All these different sedimentary rocks are formed from the broken remains of other rocks that become joined together.

It’s often assumed that all soil organic carbon ultimately derives from recent vegetation, but researchers argue that carbon inherited from parent rocks can be important and deserves more focus.