Murray Gell-Mann didn’t invent “quark,” Joyce did (in a new meaning itself), but Gell-Mann made the thing/word thing.
The word is in the opening sentence of a poetic introduction opening Book II, Chapter IV (Viking Ed, 384). It is Joyce’s redefinition, to his ear, of the sound of seabirds with an adaptation of “squawk.” The birds circle in the air gossiping about what they see.
The chapter works with the myth of Tristan and Isolde. Tristan has been mustered by his master King Mark to fetch Isolde to be his bride.
— Three quarks for Muster Mark!
After the poem is finished, the prose begins with the same picture:
Overhoved, shrillgleescreaming. That song sang seaswans.
The winging ones. Seahawk, seagull, curlew and plover, kestrel
and capercallzie. All the birds of the sea they trolled out rightbold
when they smacked the big kuss of Trustan with Usolde.
It’s nice that “quark” echoes the orthography of both “muster” and “Mark.”
The full passage (Tristan bags her for himself):
— Three quarks for Muster Mark!
Sure he hasn't got much of a bark
And sure any he has it's all beside the mark.
But O, Wreneagle Almighty, wouldn't un be a sky of a lark
To see that old buzzard whooping about for uns shirt in the dark
And he hunting round for uns speckled trousers around by Palmer-
stown Park?
Hohohoho, moulty Mark!
You're the rummest old rooster ever flopped out of a Noah's ark
And you think you're cock of the wark.
Fowls, up! Tristy's the spry young spark
That'll tread her and wed her and bed her and red her
Without ever winking the tail of a feather
And that's how that chap's going to make his money and mark!