Concentrations of N, F, Na, Mg, Al, Si, P, K, Ca, Mn, Fe, Zn, Sr and Ba were determined in fossil bones using neutron activation analysis and X-ray fluorescence methods. Analysis of the data led to the conclusion that a correlation exists between the concentration of nitrogen and the temperature at the burial time of bones. This correlation enabled the temperature for different eras to be estimated. Correlation was also found between the Al, Si and Fe infiltered into the organic part of bones.