RELATIONSHIP OF DISCONFORMITIES TO CONODONT ZONES IN THE MISSISSIPPIAN OFF MISSOURI AND ALBERTA

Sedimentation started on the craton with massive carbonate of the Little Bighorn and continued with cycles oolitic limestone alternating with silty beds starting with Sloss' Double marker across the craton (Siphonodella cooperi cooperi zone0 A drop in sealevel created a ravinement surface across the craton and an extinction of Sipoonodellids. Osage Gnathodus semiglauber formed in the Pierson beds. Thompson (1968) Baxter (unpublished 1988) noted a surface marked withe fish teeth and glauconite 10 cm above the Dolbee Creek where Polygnathids gave way to Bactrognathus distortis. Farther up at the top of the Cedar Fork the Gnathodus texanus were noted by Baxter above an irregular surface.