Sedimentology is the study of sedimentary rock, it's origin, classification, and description. Specialists in this field are called Sedimentologists. Sedimentology is closely related to paleontology at times, as the fossils help to determine deposited environment changes, as well as the age of the rock. See also Stratigraphy. Sedimentologists commonly use tools such as flumes to study bedrock forms, such as ripples, and dunes. Because of the ability for ash layers, plant material, and fossils to be dated, sedimentary rocks make up what is commonly referred to as the rock record.