Mudcracks and mudcrack polygons; a diagram illustrating their formation and burial. The lower part of the diagram shows a thin layer of mud on sand, with mud cracks well developed on the left and curved polygonal plates and ships on the right. In the background, mud is shown overlying the mud-cracked surface. The buried fragments make an intraformational sharpstone conglomerate. In the upper shale layer, V-shaped mudcracks are filled with sand. Several mud lamine separated from the main body of mud curl up along the edges. These may lie convex or concave upward. Shrock, 1948, p. 189.