It appears, however, to have been partly derived from older Eocene deposits and it occurs also as a derivative phase in later formations, such as glacial drift.
Amber is a unique preservational mode, preserving otherwise unfossilizable parts of organisms; as such it is helpful in the reconstruction of ecosystems as well as organisms;[REF] the chemical composition of the resin, however, is of limited utility in reconstructing the phylogenetic affinity of the resin producer [REF].