The New Harmony Group is located in the State of

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

. It is made up of three formations, the Grassy Knob Chert, the Backbone Limestone and Clear Creek Chert. It is

Lower Devonian The Early Devonian is the first of three epochs comprising the Devonian period, corresponding to the Lower Devonian series. It lasted from and began with the Lochkovian Stage , which was followed by the Pragian from and then by the Emsian, w ...

in age.

Stratigraphy

Eastward the group is made up primarily of the Backbone Limestone. It is very light in color, and medium to course grained limestone. The limestone itself is bioclastic. Westward it is very fine grained to medium grained limestone and dolomite with cherty inclusions. To almost pure chert. The cherty facies are the Clear Creek and Grassy Knob formations. There are tongues of chert and limestone that represent facies of each formation interlayed between one another.

Clear Creek Chert

The Clear Creek Chert is light yellowish grey to olive grey cherty limestone. Grading to predominately chert moving westward.

Backbone Limestone

The Backbone Limestone is light yellowish grey to yellowish grey. It is fine grained to course grained. There are minor cherty inclusions within the formation. There are micro and macro fossils that have been correlated with the

Oriskany Formation The Oriskany Sandstone is a Middle Devonian age unit of sedimentary rock found in eastern North America. The type locality of the unit is located at Oriskany Falls in New York. The Oriskany Sandstone extends throughout much of the Appalachian B ...

in New York State.

Grassy Knob Chert

The Grassy Knob Chert upper sections are yellowish grey to light olive grey limestone, interbedded with cherty inclusions. Moving lower the amount of chert increases and the color changed to light grey with some olive grey mottling. This formation is generally the same age as the

of the

Appalachian Basin The geology of the Appalachians dates back to more than 480 million years ago. A look at rocks exposed in today's Appalachian Mountains reveals elongate belts of folded and thrust faulted marine sedimentary rocks, volcanic rocks and slivers of ...

References

Devonian Indiana Devonian Illinois {{Devonian footer, state=expanded