Comparison of isochrones for the indicated ages and metallicities with the CMD of M67 (Montgomery et al. 1993), on the assumption of the reddening and apparent distance modulus specified in the lower left‐hand corner. The vertical line bounded by short horizontal lines, located adjacent to the turnoff, indicates our estimate of the luminosity spanned by the gap in the observed CMD. Only the dashed isochrone has a blueward hook in the same magnitude range.