Simulates collagen diagenesis using a simple conceptual model in which the degradation is controlled by two key processes: 1) depolymerization of collagen by chemical hydrolysis of peptide bonds; and 2) dissolution (i.e., melting free) of those polypeptide fragments retained by fewer than a critical number of hydrogen bonds, biodeterioration being ignored. The model predicts that the curve describing weight loss is approximately sigmoidal in form, a pattern in accord with the sparse experimental data for nonmineralized collagen. The authors conclude from studies of mineralized collagen that the weight loss curve is exponential (i.e., a first-order reaction), but argue that the experimental design of those studies was flawed. The authors decribe other predictions of the model relating to the changing size distribution of residual fragments, N-termini, physical properties, and significance of crosslinking. Crosslinking appears to be a particularly significant phenomenon, which causes a marked tailing of the weight-loss curve and thus the enhanced preservation of crosslinked, low-collagen bone.