While soils with free carbonates are rare in udic moisture regime, calcareous soils (10 to 99% CaCO3) are found along drainageways in the Ridge and Valley Region (in the Great Limestone Valley portion) of the Eastern United States. These soils have developed from biogenically derived marl deposited in freshwater, ponded, settings during the late Pleistocene to the early Holocene Epochs. Pedogenesis in these marls has resulted in calcareous soils anomalous for this region; most of the adjacent upland limestone-derived soils are slightly acid and kaolinitic. Our study investigated the pedological attributes of these soils. Six transects, including four sampling pits, were examined in marl-derived map units in the Hagerstown Valley portion of the Great Limestone Valley, and chemical and physical characterization of the soils was conducted. Micro- and macromorphological investigation of carbonate forms indicated that calcic horizons were present in these soils, which is not typical in humid regions. Most of these soils possessed mollic epipedons and buried A horizons and were Mollisols. Common limnic materials in the solum were inherited from the parent material. The recent adoption of the Lma horizon designation for layers containing marl is appropriate for some of the horizons contained in these marl-derived soils.