This is from George Orwell's Down and Out in Paris and London:
"Thereupon a whole variegated chorus of yells, as windows were flung open on every side and half the street joined in the quarrel." (pg.1, Penguin edition).
It is the first part - "Thereupon a variegated chorus of yells" - which I am interested in. I am under the impression that "chorus" is used here as a noun; therefore, there is no verb in the phrase at the beginning of the sentence, yet it gives the impression of a clause. If the sentence were as follows, "Thereupon a variegated chorus of yells.", it would still make sense to me despite the absence of any verb. Is a verb implied?: "Thereupon a variegated chorus of yells (erupted)", for example. If so, is there a name for this? I am sure I have seen it before.