Cason Shale

Cason Shale
Stratigraphic range: Ordovician-Silurian
Type	Formation
Unit of	none
Underlies	Brassfield Limestone
Overlies	Fernvale Limestone
Thickness	up to appx. 23 feet [1]
Lithology
Primary	Shale
Location
Region	Arkansas
Country	United States
Type section
Named for	Cason tract and mine, near Batesville, Independence County, Arkansas
Named by	Henry Shaler Williams [2]

The Cason Shale is a Late Ordovician to Middle Silurian geologic formation in the Ozark Plateaus of Arkansas. ^[1] The name was introduced in 1894 by Henry Shaler Williams in his study of Arkansas. ^[2] Williams designated a type locality at what was known as the Cason tract and mine, near Batesville, Independence County, Arkansas, however, he did not assign a stratotype. As of 2017, a reference section has not been designated for this unit.

Paleofauna

Conodonts

Acodus A. inornatus [3] A. unicostatus [3] Ambalodus A. triangularis [3] Amorphognatus [3] Belodella B. flexa [3] Belodina B. inclinata [3] B. ornata [3] Carniodus [3] Cordylodus C. delicatus [3] C. flexuosus [3] Distacodus D. mehli [3] D. posterocostatus [3] D. procerus [3]

Distomodus D. kentuckyensis [3] Drepanodus D. homocurvatus [3] D. simplex [3] Eoligonodina E. delicata [3] Hadrognathus H. staurognathoides [3] Hindeodella H. equidentata [3] Keislognathus K. gracilis [3] Ligonodina L. egregia [3] L. silurica [3] Neoprioniodus N. bicurvatoides [3] N. planus [3]

Oistodus O. venustus [3] Ozarkodina O. gaertneri [3] O. tenuis [3] Paltodus P. multicostatus [3] P. trigonius [3] Panderodus P. gracilis [3] P. miseri [3] P. simplex [3] P. sulcatus [3] P. unicostatus [3] Phragmodus P. undatus [3] Plectospathodus P. extensus [3] Prioniodina P. irregularis [3]

Pterospathodus [3] Scolopodus S. insculptus [3] Spathognathodus S. manganiferus [3] S. procerus [3] S. sweeti [3] S. wolfordi [3] Tetraprioniodus T. superbus [3] Trichonodella T. brassfieldensis [3] T. carinata [3] T. diminuta [3] T. exacta [3] T. variflexa [3] Zygognathus Z. mira [3]

See also

• Paleontology portal

• List of fossiliferous stratigraphic units in Arkansas
• Paleontology in Arkansas

References

1. McFarland, John David (2004) [1998]. "Stratigraphic summary of Arkansas" (PDF). Arkansas Geological Commission Information Circular. 36: 7. Archived from the original (PDF) on 2016-12-21. Retrieved 2018-01-11.
2. Williams, Henry S. (1894). "On the age of the manganese beds of the Batesville region of Arkansas". The American Journal of Science. 3rd Series. 48: 325–331.
3. Craig, William (1968). The stratigraphy and conodont paleontology of Ordovician and Silurian strata, Batesville district, Independence and Izard counties, Arkansas (PhD). The University of Texas.