Polygenetic soils are common to the Bluestem Hills region of east-central Kansas. In these polygenetic soils, the modern soil is often underlain by one or more paleosols. The modern soil is typically loess-derived, while the paleosols are usually formed in colluvium that is primarily loess mixed with small amounts of underlying bedrock. The hypothesis is that the mineralogical composition of the modern soil and paleosol differ. The objective of this study was to determine how the types and concentrations of soil minerals vary with a change in parent material stratigraphy. Two pedons were sampled and described in Chase County, Kansas, and were characterized in the laboratory. Laboratory analyses included pH, total C, cation exchange capacity, and particle size. The mineralogy of the total silt and clay fractions were semi-quantitatively determined for selected horizons with X-ray diffraction spectrometry. The horizons sampled in the modern soil contained approximately 50% smectite, and the paleosol horizons contained approximately 25% smectite. The modern soil contained no vermiculite whereas the paleosol contained up to 20% vermiculite. The kaolinite content increased with depth, and the illite content with depth. In conclusion, the mineralogy of the modern soil was dominated by smectite whereas the paleosol had a mixed mineralogy. These differences in mineralogy may have been inherent to the parent material, or they may have resulted from the different soil forming factors acting upon the modern soil and the paleosol during pedogenesis.