So much has been written about that night in the years since that fact and myth have become intertwined. Regular power-outs, a guest list of Beatles and Blow-Ups, acid casualties stalking dirt-floor stalls dosed up on acid-laced sugarcubes handed out on the door. What does Floyd drummer Nick Mason recall from that night, 50 years on? “Well obviously I can’t remember a thing, so I’ll have to invent it for you,” he laughs.
Here I can't understand the meaning of "stalking dirt-floor stalls". What is a "dirt-floor stall"