A belated thanks to Ross Campbell for explaining about the Sillees River. I stuck with the "Murlo's" version because listeners would hear "silly" and get confused.

Some here have complained that they can't find a town called Murlo, but "Murlo's crooning stream" could mean that Murlo was a landowner or tenant farmer with the stream on his place. Murlo could have been a resident who regularly visited or fished the stream, so people thought of it as his. Murlo could even have been an artist who painted the stream.