There are two substantial generalizations regarding the chemical dating of bone: 1) There exists in fossil bone a number of substances, the removal or accumulation of which follow a well- established secular trend. Ideally, these should furnish a battery of dating indices. However, in practice, each such index must be treated on a statistical basis, leaving partially unsolved the problem of the date of the individual bone, and; 2) The errors introduced by apparently random variation can be reduced and the indices systematized only if the quantities of substance found in the bone be adjusted to conform with the environmental soil conditions which regulate rates of decomposition. We are at present at an impasse. A real breakthrough can occur only as a result of a renewed study of the chemistry and physics of soil and fossilization.