Green’s Dictionary of Slang

a gathering of beggars.

1821		Egan Life in London (1869) 374: You ought not [...] return to Hawthorn Hall without taking a peep at the Cadgers, at the Noah’s Ark, to use the slang of the Oxonian, in the back slums, in the Holy Land.
1822		Tom and Jerry; A Musical Extravaganza 54: Noah’s ark, beggar’s assembly.