Question

What do sedimentary rock layers reveal about ancient environments?

Answer 1

The most comprehensive story of ancient environment is traced by type of Sedimentary rocks. The different ancient environment forms different kinds of sedimentary rocks in terms of shape, size, pattern of sorting etc.

For example:

an ancient environment of lake will have laminated sedimentary rocks while a deserted one will have cross beds or granules.  

Not only this we can also have an idea about the kind of flora and fauna of ancient environment based on the fossils.  which may be in the form of architectural features.

So they reveal both kind of life / living organism and the kind of earth like river, desert, lake, swamp, lagoon etc.