A recent Language Log post discusses the use of nor in the sentence:
"The snow fell nor did it cease to fall."
Since this topic touches on disjunction and ultimately on wh-words (interrogative pronouns), central issues in my dissertation, I can (almost) justify taking the time to investigate some of the antecedents of McCarthy's use of nor. Nor in the above sentence, as Mark Liberman observes, conforms to the sense in the OED's entry 5a. for nor:
5. And — not; neither. In later use normally with inversion of subject and verb.a. Following an affirmative clause, or in continuing narration. Obs. (chiefly poet. in later use).
Liberman offers discussion of modern and (late) early modern English examples in the aforementioned Language Log post; I shall concentrate on earlier examples, such as:
 Guildhall Let.-bk. in R. W. Chambers & M. Daunt Bk. London Eng. (1931) 114 He shalle wirke..without fraude..nor he shall nat entermete of sekenes, sore, or hurte..vnknowynge to hym in eny maner.[1492-3] in T. Pape Medieval Newcastle-under-Lyme (1928) 180 The aforesaid William shall delyuer all evedence and writings that belonges to the lands in the Newcastle, nor hurt nor truble the aforesaid John Leighton. LD. BERNERS tr. J. Froissart Cronycles I. cxxxv. 162, I greatly desyre to se the kynge my maister, nor I wyll lye but one nyght in a place, tyll I come there.
These are the three earliest examples the OED gives for sense 5a. It is interesting to note that the first two appear to come from legal documents.
The OED suggests that nor derives from earlier nother1 (a contracted form of Old English nōhwæðer "neither", on which more presently), for which its earliest example means "neither of two preceding things or persons":
[eOE] KING ÆLFRED tr. Gregory Pastoral Care (Hatton) li. 399 Ne fornime incer noðer oðer ofer will butan geðafunge."Let neither of you deprive the other without consent."
As Mitchell:§§1847-51 observes, OE nohwæðer/noðer cannot always be interpreted as a pronoun, as in:
[Blickling Homilies:45.14]...þæt hi þonne ne mihtan nawþer ne him sylfum ne þære heorde þe hi ær Gode healdan sceoldan, n