H. B. Willman and John C. Frye
The Jules Soil is named for Jules, Cass County, from its occurrence in the Jules Section (Frye, Glass, and Willman, 1968). Its occurrence has also been described in the Cottonwood School (table 6) and Frederick South (table 7) Sections.
|Table 6 -- Stratigraphic Sections (partial)|
The following 21 stratigraphic sections describe exposures in Illinois and illustrate many of the aspects of Pleistocene stratigraphy. These sections contain the type localities for 21 rock-stratigraphic units, 4 soil-stratigraphic units, and 3 time-stratigraphic units and include paratypes for several other units. The sample numbers preceded by "P" are the numbers used in the Illinois State Geological Survey collections. Analytical data on many of these samples are on file at the Survey. The sections are arrange alphabetically by name.
It merits recognition as a named buried soil because it can be readily observed in the field, and mineralogical studies (Frye, Glass, and Willman, 1968) have shown that it marks the boundary between two zones in the Peoria Loess. These two zones cannot be distinguished in the absence of the Jules Soil. However, they show that the Jules Soil correlates with the boundary between the Tiskilwa and Malden Till Members of the Wedron Formation.
The Jules is the most weakly developed of the formally named soil-stratigraphic units in Illinois. It commonly is an "A-C" profile and lacks a textural, or structured, B-zone. Furthermore, at some places it splits into two or even three A-zones separated by as much as 1 to 1.5 feet of somewhat weathered loess. It has been observed only in the thick loess sections adjacent to the Illinois River Valley. It occurs only within the Peoria Loess.
FRYE, J. C, H. D. GLASS, and H. B. WILLMAN, 1968, Mineral zonation of Woodfordian loesses of Illinois: Illinois State Geological Survey Circular 427, 44 p.
|Stratigraphic Code||Geo Unit Designation|