Imagine you are a geologist standing in front of a large outcrop of sandstone, shale, and limestone ...

1. Order in which rocks were deposited gives you relative dates of facies, and climatic
conditions (marine regression or transgression)
2. Composition of rock, in combination with other factors, can tell you source area of
sediments (in case of sandstone) or narrow down environments (in case of limestone).
3. Textural properties such as grain size, sorting, and rounding can indicate the energy level
of the depositional environment, distance travelled, and/or the method of transport (wind or
water).
4. Sedimentary structures. Every depositional environment has unique processes that create
characteristic sedimentary structures like crossbeds, mud cracks, etc. that can be used for
identification.
5. Fossils. If organisms are fossilized where they lived, they can give geologists a wealth of
information about past environments.
6. Geometry of the rock layers can be useful in conjunction with other factors to determine
past depositional environments. Certain deposits have characteristic shapes.