Halliday & Matthiessen (1999: 180, 181):
Finally, the structures of both types of group constitute a kind of path between the interpersonal reference point, reflected in the Deictic or Finite, and the experiential one, reflected in the Thing or Event But in the case of the verbal group, the path is made up of one or more temporal relations: past/present/future in relation to a moment in some dimension of time construed between 'now' and the time of the occurrence of the event; for example, see Figure 5-3.
In the nominal group, on the other hand, the path from Deictic to Thing is not a chain in time — alt[h]ough it does reflect time in another way. The path goes through qualities of various kinds, beginning with qualities that are textual and transitory (unstable in time) and moving towards increasing permanence (time-stability) and experiential complexity.
