A description of structures in the exposed Precambrian rocks of the Canadian shield may be of some assistance in understanding the basement structures beneath the surrounding Phanerozoic cover. The shield is divided into a number of structural provinces and corresponding orogens. These differ from one another in age and, in each of the regions, structural trends are described in relation to the orogeny or orogenies responsible for their development. As a rule, the trends are so complex and intricate that they cannot be projected for useful distances beneath the surrounding cover. Locally, Precambrian fault scarps projected from the shield had an influence on depositional features in the overlying rocks. The orogens themselves form structural units of large size and, espec ally along their contacts with one another, possibly has some influence in controlling epeirogenic movements producing basins and "highs" in the cover.