The Ordovician has the same components as the Cambrian with additional limestone, sandstone and clay intercalations at the bottom. This layer is about 153 meters thick in the northwest and 53 meter thick in the southwest. The Silurian is about 640 meters thick in the southwest and 60 meter thick in the northwest. This layer consist of limestone, marls, and dolomites. The Devonian includes all the stages, with the early Devonian predominantly found in central Belarus.