The four Meramecian limestones in the Hugoton embayment appear to be synchronous with the equivalent formations in the Mississippi River Valley. Thus, little or no time transgression is indicated between western Illinois, eastern Missouri, and Kansas. Some additional elements appear in the Meramecian fauna of western Kansas, particularly in the bar and blade forms, but the platform species, generally considered to be more time-sensitive because of more rapid evolution, show little variation from region to region. Therefore, the Meramecian units of eastern Kansas are considered to be of the same age as corresponding strata in western Kansas, and are correlated on this basis.
The "Cowley Formation" was named and defined by Lee (1940) as early Meramecian in age, and he concluded that it rests on an erosional surface produced at the end of Osagian time. The conodonts recovered from rocks called "Cowley" indicate the upper portion to be as young as late Meramecian (Core L), whereas the lower portion may be as old as early Osagian. This information leads to the conclusion that the "Cowley Formation" is a facies variant of the typical limestone strata of early Osagian to late Meramecian age found elsewhere in Kansas.
Conodont faunas found in the St. Louis Limestone in wells in Comanche, Barber, and Harper counties (Cores I, J, L) place late Meramecian rocks where previously Warsaw strata were reported as the youngest Meramecian rocks present in the central portion of the Sedgwick basin in Kansas (Merriam, 1963, p. 171, fig. 4). Likewise, the youngest Meramecian rocks in the Cherokee basin appear to be St. Louis equivalents (Cores M, N, O), only Warsaw having been previously reported (Lee, 1940). Here, beneath St. Louis rocks, a relatively thin Salem sequence is underlain by Warsaw rocks.
The outcrop material in extreme southeastern Kansas provides information for a significant change in the interpretation of the distribution of Meramecian rocks in Kansas. This section was previously referred to the Warsaw Limestone. However, the conodont fauna recovered from these rocks indicates a late Osagian age, or Keokuk equivalence. Thus, there is some doubt that any significant amount of Meramecian rocks is present in the Mississippian outcrop belt in southeastern Kansas.
Kansas Geological Survey, Geology
Placed on web June 24, 2010; originally published Dec. 1968.
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