This thesis is an examination of the pattern of bone maintenance with age in a 19th century population of settlers from Belleville, Ontario, Canada. It was hypothesized that cortical bone thickness can be used as a proxy for cortical bone area and that females should exhibit a greater amount of bone loss than males. The total area, medullary area, cortical bone area and cortical bone thicknesses at the midshaft of the left femur of 206 individuals (121 males and 85 females) were measured. The results indicate that males gained bone mass from the third to the sixth decade followed by a nonsignificant decline in the seventh decade. Females exhibited maintenance of the same bone mass until the seventh decade when there was a significant decline. Combined cortical thickness as well as anterior thickness were regressed onto cortical area. There is a stronger relationship between combined cortical thickness and cortical area than between anterior thickness and area. Cortical thickness is a reasonable proxy for cortical area. The hypothesis that males and females exhibit a different pattern of bone maintenance was supported (Spearman's correlation coefficient is significant at the 0.05 level).