H. B. Willman and T. C. Buschbach
The Chazyan Stage (Emmons, 1842, p. 107; Grabau, 1989, p. 223) is named for Chazy, New York.
The Everton is correlated with the type Chazyan on the basis of the fauna in the Everton type area in Arkansas and by subsurface tracing (Templeton and Willman, 1963).
Extent and Thickness
In Illinois the Chazyan Stage includes only the Everton Dolomite, which is not exposed but is encountered in drilling in the southwestern part of the state.
EMMONS, EBENEZER, 1842, Geology of New York, Part 2, comprising the survey of the second geological district: Albany, 437 p.
GRABAU, A. W., 1909, Physical and faunal evolution of North America during Ordovicic, Siluric, and early Devonic time: Journal of Geology, v. 17, p. 209-252.
TEMPLETON, J. S., and H. B. WILLMAN, 1963, Champlainian Series (Middle Ordovician) in Illinois: Illinois State Geological Survey Bulletin 89, 260 p.
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