Planar vertical joints and straight en échelon cracks are closely associated in an erosional exposure of Middle Eocene chalks in a syncline south of Beer Sheva. The two dominant joint sets are oriented 357° (N3°W) and 031° (N31°E) and both sets occur in two separate outcrops 400 m apart. An en échelon crack array accompanies each joint set. The individual en échelon cracks are oriented 337 and 053°, respectively. Radial plumose markings are present on the surfaces of the en échelon cracks. They imply that fracture occurred normal to a local tensile stress axis. A gradual rotation of the azimuths of the joints and cracks occurs between the two outcrops; this rotation implies jointing due to NNE-SSW compression and en échelon cracking due to unloading of this compression.