near Clawson, Utah, at a claim known as “Septarianville.” This gray and dreary landscape is dominated by the presence of the Mancos Shale (Cretaceous), and the nodules are found in the lowermost member.
Large nodules exposed along the bedding plane. One needs to work slowly with chisels and crack hammers in order to extract one of these monsters.
Small, whole nodule on left, with a cracked specimen showing interior filled with calcite and aragonite.
This large nodule broke into three beautiful parts.
Close-up of nodule interior filled with amber or white/clear calcite surrounded by dark, blackish to red bands of aragonite and also filled with sharp rhombohedral calcite crystals.