Charles Collinson and Elwood Atherton
The Kaskaskia Sequence is named for the Kaskaskia River in south-central Illinois.
The major unconformity at the base of the Middle Devonian Series, or in some areas the base of the Upper Devonian Series, is widely present throughout the eastern part of the United States, and the strata between the unconformity and the next higher major unconformity (which in Illinois is at the base of the Pennsylvanian System) are called the Kaskaskia Sequence (Sloss et al., 1949) (fig. 14). The original definition of the sequence placed its top at the base of the Mississippian Aux Vases Sandstone, excluding the Chesterian Series. However, because the sub-Aux Vases unconformity is confined to the margin of the basin and the Chesterian strata generally have the same structural attitude as the underlying Valmeyeran Series, the Kaskaskia was extended upward to the base of the Pennsylvanian System (Swann and Willman, 1961).
SLOSS, L. L., W. C. KRUMBEIN, and E. C. DAPPLES, 1949, Integrated facies analysis, in Sedimentary facies in geologic history: Geological Society of America Memoir 39, p. 91-123.
SWANN, D. H., and H. B. WILLMAN, 1961, Megagroups in Illinois: American Association of Petroleum Geologists Bulletin, v. 45, p. 471-483; Illinois State Geological Survey Reprint 1961-N.
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