in which a fold is facing, while others believed the definition to coincide with its original use by Stille, which was the direction of the up-dip direction of a fold on an axial surface. The disagreement likely derived, because Stille was not explicitly clear about the direction of the overturning of folds following the up-dip or down-dip of the fold. In his original use of the term, however, he did, in fact, use the up-dip direction of the fold. The main reason this creates confusion is a result of the common definition of fold-facing in geology, which is described as the direction (normal to the axis of a fold and corresponding to the axial plane) that points towards younger beds. As a result of this definition, two folds, which possess identical asymmetry, can be seen as facing opposite directions in relation to the stratigraphic elements of the structure, resulting in differently interpreted directions of vergence. In order to clear up this confusion, geologists have attempted to create a more definitive definition of vergence. The now, more widely accepted definition of vergence, which is used to help describe the geometric component of asymmetry in a fold, is the horizontal direction in which the upper component of rotation in a fold is directed. In this definition, the concept of vergence is distinguished from and independent of the facing component of a fold. Based on this independence, much of the confusion has been cleared up, and both concepts of vergence and facing are of important use to geologists, especially in the analysis of more complex structures. Understanding Vergence in Folds One of the main uses of vergence is to give an idea to the overall geometry of a fold by describing the symmetry or asymmetry of a fold. To better understand the importance of this use, it is important to understand the different classifications of folds, based on their geometry. The most commonly used terms to describe and classify folds, based on their geometry, are the terms antiforms and synforms, as well as anticlines and synclines. Although these terms sound similar, they mean very different things in reference to the geometry of a fold. When the limbs of a fold converge upward, the fold is referred to as an antiform. Conversely, when the limbs of a fold converge downward, the fold is known as a synform. Not to be confused with these terms