“…This can be demonstrated by (a) the alternation of chert bands and carbonate beds is at casual intervals (does not coincide with the stratum boundaries; e.g., Shaaban, ), (b) the inconstant thickness and lateral nonpersistence of the chert bands throughout the single bed (e.g., Genedi, ), (c) the sharp contact between the chert and the host carbonates (Figure a; e.g., Abd El‐Hameed et al, ; Bustillo & Ruiz‐Ortiz, ; Conglio, ; El‐Mansey & El‐Baz, ), (d) the presence of chert within limestones of diverse depositional textures (wackestone, packstone, grainstone, etc.) implies that the distribution of chert is not related to the depositional environments of their host limestones and accordingly attributed the origin of chert to postdepositional changes (e.g., Gao & Land, ; Knauth, ; Maliva & Siever, ), (e) the presence of allochems similar to those identified from the host carbonates but with conspicuous signs of silicification (e.g., Madsen & Stemmerik, ; Maliva, ), (f) the freezing of most of the depositional textures of the carbonate host rocks (Figure g; e.g., Hesse, ; Maliva & Siever, ; Meyers, ), (g) the partial replacement of the lime mud matrix and allochems of the host limestone by silica (Figures f, c; e.g., Bustillo, Delgado, Rey, & Ruiz‐Ortiz, ; Mansour, ; McBride et al, ), (h) the existence of silicified fossils within the host limestones in some horizons (Figure h; e.g., Bustillo & Ruiz‐Ortiz, ; Maliva & Siever, ; Schubert, Kidder, & Erwin, ), (i) presence of opal‐CT in the form of microquartz‐replaced lepispheres (Figure e; e.g., Genedi, ; Maliva & Siever, ), and (j) replacement of dolomite by quartz (Figure h; e.g., Migaszewski et al, ; Raviolo, Barbosa, & Neumann, ; Whittle & Alsharhan, ). Moreover, the presence of different colours of the studied chert (grey, brown, and black) provides insights about the progressive stages of silicification (e.g., Kwiatkowski, ).…”