A compound is a substance that contains two or more elements close elementA pure substance that is made from only one type ... limestone, shale, and sandstone are all examples of sedimentary rocks.

These sedimentary rocks are born from the decay and fossilization ... and sandstone. Put simply, limestone is a type of rock that is formed by organisms, while gravel is a mixture of many ...

There are three main types of rock: igneous rock ... to bury them and shelter them from scavengers and decay. Mudstone, shale, and limestone are examples of sedimentary rock likely to contain fossils.

Studies of modern limestone have led ... reserves are held in carbonate rock, yet extraction from carbonate reservoirs can be very challenging and much of the oil and gas often remains un-recovered.