IA. Natural cobbles with wear on one surface. Cobbles range from symmetrical to irregular in shape: circular to ovoid in outline.
IB. Extended form of type IA, showing excessive wear. Forms all tend toward symmetry.
IC. Elongated “sugar-loaf” in cross section. Entire back surface completely smoothed.
II. Bifaced
IIA. Natural cobbles with wear on two surfaces. Symmetrical forms range from oblate spheroids to ovoid disks, others are symmetrical. In cross section wear surfaces are parallel to lenticular. Grades into type IIB.
IIB. Same as IIA, but forms are elongated (length always much greater than the breadth).
IIC. Wedge-shaped, ovoid to elongate cobbles. Angle between wear surfaces ranges from 5 degrees to 45 degrees.
IID. Same as type IIC, but one surface is keeled as a result of superimposed wear pattern.
III. Trifaced
III. Long, narrow, triangular cross section.