stratigraphic facies . Facies distinguished primarily on the basis of form, nature of boundaries, and mutual relations, to which appearance and composition are subordinated (Weller, 1958, p.627). These facies are all stratigraphic bodies of one kind or another; they may occur in vertical succession and have boundaries that are more or less horizontal stratigraphic planes (e.g. systems, formations, biostratigraphic zones, and lithostromes), or they may be laterally intergrading parts of some kind of a stratigraphic unit and separated at more or less arbitrary vertical cutoff boundaries (e.g. lithofacies), or they may bear both lateral and vertical relations to each other and have irregular boundaries (e.g. the magnafacies of Caster, 1934). See also: facies. Cf: petrographic facies.