Green’s Dictionary of Slang

an Irish thug, the equivalent of a London Mohock n., who specializes in roaming the streets and slashing the face of any unfortunate victim; thus chalking, carrying out this species of urban terrorism or ‘amusement’ as Grose (1785) grimly notes it.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Chalkers, men of wit in Ireland, who in the night amuse themselves, with cutting inoffensive passengers across the face with a knife. They are somewhat like those facetious gentlemen, some time ago known in England, by the title of sweaters and mohocks. [Ibid.] Chalking, the amusement above described.
1811		Lex. Balatronicum.
1847		J.E. Walsh Ireland Sixty Years Ago (1885) 20: While the punishment for ‘chalking’ is made in the highest degree severe, it is provided that the offence shall not corrupt the offender’s blood.