![]() ![]() These beds are under study for their role in the destructive and fatal 2001 Yaggy/Hutchinson natural gas storage leak. Three-finger dolomite is an approximate 20 foot zone containing three relatively thin dolomite beds, informally named in south-central Kansas. One outcrop is in the bank of the Chikaskia River south of Milan, Kansas, where it consists of three beds of dolomite separated by shale, all with green flecks of malachite. Its appearance is typically a succession of discontinuous, thin carbonate beds. Milan Limestone is the marker bed for the top of the upper Wellington, but it is not always present, its absence visibly obscuring the contact with the overlying Ninnescah Shale. The upper Wellington consists primarily of interbedded cycles of gray anhydritic mudrock and red mudrock, but includes limited beds of discontinuous limestone and dolomite. Like the salt, each is not always recognizably present. Some limestone beds, typically dolomite, are observed within these upper and lower shale divisions, variously ranked as members, and the otherwise unnamed adjoining shales may be classified with the named limestones. However, these informally named divisions are based only upon the position of the Hutchinson Salt Member in the general middle of the formation, which is usually but not always present. ![]() Broadly, the Wellington shales are divided into an upper Wellington shale member and a lower Wellington shale member. The Wellington is not particularly rigorously divided into subunits as few easily identifiable features are consistent other than the dark shale but certain subdivisions are recognized. Asthenohymen minutus, large Permian insect.Meganeuropsis permianum, largest known winged insect. ![]()
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