  The material structure of bodies undergoing growth is considered. In the
geometric framework of a general differential manifold modeling the physical
space and a fiber bundle modeling spacetime, body points may be defined for any
extensive property for which a smooth flux field exists, even if the property
is not conserved. Singular flux fields are considered using the notion of a de
Rham current. Writing a generalized balance law using the boundary of the
current corresponding to a singular flux field, surface growth is unified with
volumetric growth.
