Abstract: A modular wall block is formed with a groove in a top surface configured to frictionally receive fingers of a rake-like connection device which may extend through apertures in an end portion of a grid-like sheet of reinforcing material. The connection device includes enlarged tabs projecting away from the fingers to engage in a widened slot defined in the bottom of superimposed wall blocks for positioning the front faces of the blocks in the retaining wall relative to each other in either a vertically aligned or vertically set back relationship depending upon the direction of extension of the tabs. The groove and the slot are formed at opposite ends of a tapered through-opening extending between top and bottom surfaces of the block. By virtue of the taper, the width of the groove is less than a width of the slot to accommodate the different portions of the connector device.