Abstract: Apparatus for filling cartons having three upstanding side walls and a horizontal side wall with stacks of paper sheets has a horizontal conveyor reciprocable into and from a carton while the carton is held at a filling station, a system for delivering stacks to that portion of the conveyor which enters a carton at the filling station, and a locating device installed at a level above the path of movement of stacks with the conveyor portion and having an indexible horizontal shaft for two fingers which are disposed opposite each other, and an indexing mechanism for the shaft. The shaft is indexed to a first position in which one finger extends into the path of movement of an oncoming stack during delivery of the stack onto the conveyor, thereupon throuh 90.degree. to ensure that the fingers cannot interfere with introduction of the stack into the carton, and again through 90.degree.