Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.
H. B. Willman and T. C. Buschbach
Chazyan Stage (Emmons, 1842, p. 107; Grabau, 1989, p. 223).
Named for Chazy, New York.
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.
Well log characteristics
Age and correlation
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).
Environments of deposition
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.
|Stratigraphic Code||Geo Unit Designation|