premise: Taking page 17 again, I was reminded that Giles is rather given to semi-serious poetic diction at times, and we find him referring to the presence of water in the Finke River as  the stream purling over its stony floor  or, quoting some bygone poet,  brightly the brook through the green leaflets, giddy with joyousness, dances along. 
hypothesis: I was reminded the Giles tends to be poetic.