Abstract: A roll forming machine picks up crop material and forms, twine wraps and discharges rolls or large round bales thereof as the machine is continuously moving across the field. The machine has a mobile frame supporting a pickup and a floor, the latter supporting a lower conveyor. A front upper apron is supported on the frame above a front portion of the lower conveyor and floor and defines a front roll forming region therewith. A rear upper apron is supported on the frame above a rear portion of the lower conveyor and floor and defines a rear roll forming region therewith. Formation of a crop material roll is initiated in the front region and completed in the rear region after the roll has been partially formed in the front region and transferred to the rear region. Mechanism on the frame is operable to lower or raise a rear end of the front upper apron in order to correspondingly initiate formation of a roll in the front region or permit transfer of the roll to the rear region.