Abstract: A head assembly for a cotton harvesting machine which provides many combinations of row widths and various row harvesting capacities. The head assembly includes a main cross auger frame with row unit support structure which slidably receives a plurality of vertically adjustable row units. The support structure permits simultaneous transverse adjustment of each individual row unit and its associated hydraulic lift cylinder. An extension frame is provided for adding extra row units for increased capacity or accommodating widely spaced rows of cotton. Row units and lift cylinders are freely slidable between the main frame and the extension, and the extension is removable to lessen machine width during transport. The main cross auger frame includes a pair of transversely spaced bearings which journal opposite ends of a main cross auger. An auger extension is attached to a shaft which extends through the extension end bearing to eliminate need for relocating the bearing or providing a telescoping auger.