Robert J. Schork reacts to the exclamation “holy saint Denis” in a footnote to his Joyce and Hagiography: Saints Above! (p. 205):
From both national and devotional points of view, I cannot explain Gerty MacDowell's [sic] exclamation in "Nausicaa": "holy saint Denis" (U 13.395).
This is all the more surprising as he quotes from Paul Mercanton’s memory of Joyce in the preceding lines that Joyce “was astonished that Saint Denis meant nothing to the French”.1 Mercanton’s following lines are enlightening:
Nevertheless, in "Nausicaa" he put an invocation to Saint Denis in the mouth of one of the young girls on the beach, just as he had once heard it, for he made up nothing.
Mercanton is undoubtedly quoting Joyce here, and we should rest assured that the girl’s invocation to “Saint Denis” (the patron saint of France) was authentic. St Denis was not unfamiliar to the Irish, and he appears in the opening line of a popular song praising St. Patrick, sung to the tune of “The Night Larry before was stretched”:
A fig for St Denis of France —
He's a trumpery fellow to brag on;
A fig for St George and his lance,
Which spitted a heathenish dragon;
And the Saints of the Welshman or Scot
Are a couple of pitiful pipers;
Both of whom may just travel to pot
Compared with that patron of swipers;
St Patrick of Ireland, my dear!
Tait's Edinburgh Magazine (1839), p. 290
The exclamation Joyce once heard on a Dublin beach had obviously been handed on to the girl by her parents’ and grandparents’ generation, as in the following examples either the writers or their characters all have an Irish background:
— the divil a bit you've had man at all to eat with that old crone; I've been watching her all the time, and by the holy St. Denis of France I'll take my bible oath that she ate more than any four persons at the table.
Isaac Butt, Irish Life, 1840, p. 272
... but had'nt I been handy wid my legs in scaping from that divil Glanville, and his imps, by the holy St. Dennis, they'd have showed me as much mercy as a thumb nail would to a flay.
I. Laver, Rockland castle, 1842, p. 27
"Eh! What! How -?" ejaculated the astounded pilgrim. "Holy saint Denis! What's this at all! Why don't ye behave yersilf, ye great omadhaun!
All the Year Round (1895), p. 161
Holy Saint Denis! lamb has not crossed my mouth this season. And the day before that?' 'We had,' replied Mr. Flyn, 'two rabbits and a salmon.'
Gentleman's Magazine (1889), vol. 4, p. 228