Green’s Dictionary of Slang

(US) $1; usu. in pl.

1886		E.L. Wheeler N.Y. Nell 12: Bet a clam [HDAS].
1893		Watchman & Southron (Sumter, SC) 4 Oct. 1/6: For the first fifty years in this country, clam shells were used for money. Originally in New York six pieces of ‘wampum’ or clamshells were worth a Dutch ‘stiver’.
1909		Commoner (Lincoln, NE) 7 May 15/2: I once refused to buy the site of Chicago for four clam shells and a quart of rum.
1914		Day Book (Chicago) 12 Feb. 32/2: This is Saturday, the day Bill cops the weekly jingle, the clam shells.
1917		J. Lait Gus the Bus 53: That there is wort’ t’ree hundred clams.
1927		K. Nicholson Barker 149: Clam shells – Silver dollars.
1929		S.J. Perelman Dawn Ginsbergh’s Revenge 121: Izzy’s grandpaw [...] left him half a million clams.
1940		J.H. O’Hara Pal Joey 31: I hit a crap game for about eighty clams.
1947		B. Schulberg Harder They Fall (1971) 206: Vince’s guy was working overtime to earn his fifty clams.
1958		Mad mag. May–June 48: Trigger Grslx is in for about eight clams.
1959		W. Burroughs Naked Lunch (1968) 178: Bank notes run as high as one million clams a note.
1964		H. Selby Jr Last Exit to Brooklyn 99: Not bad eh Tral? 250 clams.
1973		M. Scorsese Mean Streets [film script] 29: I don’t owe anybody 2,000 clams.
1981		J. Ellroy Brown’s Requiem 179: Around midnight I gave Walter his six hundred clams and sent him off in a cab.
1990		S. Morgan Homeboy 362: He fined her a hundred clams.
2002		D.H. Sterry Chicken (2003) 161: Five hundred clams to rough up a judge? [...] Sure, why not?
2021		J. Ellroy Widespread Panic 51: I laid twenty clams on Gerry.