The term 'stone-line' was defined in 1938 by C.F.S. Sharpe for a line of stones at the base of soils in the Appalachian piedmont of the southeastern U.S.A. However, antecedent synonyms, such as 'pebble band' and 'pebbly concentrate', existed long before 1938 in the midcontinental area of North America. Late in the 19th Century in Iowa and Illinois, for example, the 'pebble band' was observed to mark the top of the reddish B horizon of the Sangamon and other buried soils, the "ferretto zone" as well drained members were then called. But what early workers and later ones had actually described as the "ferretto" and its "pebbly concentrate" was only part of the Sangamon soil -- its stone enriched and oxidized uppermost B horizon. They failed, understandably, to recognize the Sangamon A and E horizons, which had been blurred and altered during and after burial via mixing (bioturbation), overprinting, and other pedodiagenic processes. They also failed to recognize that the stone-line is the lower part of a biomantle and a normal product of soil formation, mainly bioturbation. But such term-concepts as 'bioturbation' and 'biomantle' were not then available to these early workers, both having been introduced much later, respectively in 1952 and 1975. Consequently, owing to the unavailability of term-concepts to describe key pedogenic processes at the end of the last century, a simplistic and incorrect explanation was advanced that soils with stone-lines had been truncated by erosion before burial, and that stone-lines were thus geogenic, not pedogenic, in origin. This simple geogenic explanation was continued by mid-twentieth century soil scientists and geologists, for example Kellogg and Ruhe, a misconception, unfortunately, now firmly embedded in the concept of 'lithologic discontinuities'.

This early misconception is understandable for two principal and interrelated reasons: First, geological principles, not pedological ones, were employed in early soil investigations, a fact which links to the second reason; that many modern concepts and terms of pedogenesis and pedodiagenesis, such as overprinting ('welding'), pedoturbation (bioturbation, etc.), pedotranslocations, plus others which describe complex but real pedogenic processes are recent conceptual constructs that were not available to early researchers. The lesson here is that lack of terms which describe fundamental processes and which convey essential concepts in a science can retard that science. Truth then plays catch-up following later formulations of such constructs. But science, fortunately, is a self-correcting enterprise, and 'truth catch-up' invariably occurs.