The internal stratigraphy of the Great/Main Limestone over the Alston Block, Stainmore Trough and the Askrigg Block is described. The occurrence and distribution of Gigantoproductus, Latiproductus, Dibunophyllum and other macrofossils are recorded. Locations where chert-rich bands have been recorded, and where evidence of bioturbation occurs, are described. Areas of localized thinning and their relationship to thick developments of sandstone and chert above and below the limestone are also noted. These variations are related to the structural features of the region.