How does David Malouf use imagery in Remembering Babylon?

Imagery:

"To the north, beginning with the last fenced paddock, lay swamp country...The land to the south was also unknown. Settlement up here proceeded in frog-leaps from one little coastal place to the next. Between lay tracts of country than no white man had ever entered. It was disturbing, that: to have unknown country behind you as well as in front."

"There was just one of them; and the thing, as far as he could make it out through the sweat in his eyes and its flamelike flickering, was not even, maybe, human."