We have found that there is considerable overlap in environmental fields defined by linear discriminant functions we have derived from either of two sets of sediment-size data--the four moment statistics; the cumulative weight percentages. The environments we have investigated are the classic ones--beaches; dunes: river bars. The samples number 970 and are from 40 American localities. The size analysis is by settling-tube methodologies, and the size-class interval is 0.1 phi . The overlap in the fields indicates that there would be a relatively high probability of error associated with the identification of an unknown. Uncertainty levels for an identification are estimated at 25 + or - 15 percent, if one of the three environments could be eliminated by other evidence, and 35 + or - 15 percent, if one of them cannot be eliminated.