Major stratigraphic trends in Castlemar Conemagh: Presence of marine zone between Brush Creek and Lower Bakers town. Occurs locally above Buffalo sands tone. Development. Max. = Coal (thin) overlain by marine shale (fossils) and underlain by calcareous underclay. A considerable thickening of the L.B. - B.C. interval accompanies the occurrence - also peripheral zone marked by 1. Increased L.B.-BC interval 2. Limey clays of underclay type at about 68% 65' above B.C. Further from holes with marine zone LB-BC interval decreases and red bed - often with calc. nodules, comes in at the horizon.