Fossil amphibian specimens can be found in this section. During the Carboniferous and Permian periods, amphibians along with insects where the most dominant land animals to be found around the globe. They grew to large sizes yet their skin required moisture from water meaning they could not fully dominate the land. However, evolution would soon give them hard egg shell and water tight skin resulting in the evolution of dinosaurs. Amphibian fossils can be rare, and delicate as the fossilised remains tend to be found in very fragile matrix such as mudstones, shales, marls and siltstones.