Archetypal Matter

The “transformation of the world of nature—including, of course, the human body—from a nature consisting of Archetypal Matter to a nature consisting of matter as we know it,” Burgeon explains in Unancestral Voice, was “an event occurring in history” (117).

Prior to the fall of man, and under the rule of original participation, the world—not yet separate and detached, not yet objective—appeared, to non-materialistic thinking, to be made of Archetypal Matter (which Burgeon also calls “Edenstuff” — a more Germanic designation):

It seems to me [Barfield explains—again through his mouthpiece Burgeon, this time in Worlds Apart] that the paradise—imago—or myth, or story—is in a way the symbol par excellence. I imagine this is why it is so universal and why it has so many ramifying significances. It is the symbol of symbols; because it symbolizes, not so much any single, non-physical archetype, but non-physical existence in general—non-physical existence as such. You will never understand symbols until you have grasped that pre-historic man in his unconscious goes back, not to the animal kingdom, as the nineteenth century fondly imagined, but to a paradisal state when there was no death, because there was no matter.
(Worlds Apart 159. Burgeon is speaking)

With Leibniz (and German idealism generally), Barfield would agree that what we now think of as matter should be properly conceived of as coagulum spiritus.