Ternary diagrams can be useful in taphonomic analysis. When the quality of preservation of a hard part can be expressed in a three-fold scheme, a single point on a triangular diagram characterizes the frequency distribution of taphonomic alteration within a sample. Comparison of samples with such a "ternary taphogram" is an efficient way to explore variation in the preservation of hard parts. To illustrate the method, we compare samples from the northern Gulf of California and the North Sea. Taphonomic variation in the samples reflects variation in the extent of subaerial exposure, wave and current regime, and shell architecture.