Chevalley scheme

A Chevalley scheme in algebraic geometry was a precursor notion of scheme theory.
Let X be a separated integral noetherian scheme, R its function field. If we denote by the set of subrings of R, where x runs through X, verifies the following three properties

For each, R is the field of fractions of M.
There is a finite set of noetherian subrings of R so that and that, for each pair of indices i,j, the subring of R generated by is an -algebra of finite type.
If in are such that the maximal ideal of M is contained in that of N, then M=N.

Originally, Chevalley also supposed that R was an extension of finite type of a field K and that the 's were algebras of finite type over a field too.