This image illustrates the first three stages of a typical cyclothem as found in eastern Kansas and western Missouri. **Stage 1, Outside Shale (non-marine). **Stage 2, Middle Limestone (fast-rising seawater). **Stage 3, Core Shale (deep seawater). **In situ, shale layers are often seen as slumping hillside. As the Hushpuckney Shale layer in this photo, the shale is covered with soil and not seen. **Middle Limestone often has beds separated by a thin shale layer - as we see here with the Middle Creek Limestone's two relatively thin beds of limestone separated by a very thin layer of shale. The two limestone beds range from 0.5 to 1.5 ft in thickness, and the thin shale layer is just a fraction of an inch. Here, you see the effects of water erosion on the two separated layers of limestone. (Bed of Cedar Creek in Lees Summit, Missouri)