Limestone Reef, Rose Hill 9:0 main lim., North the Potomac R. Here are shown no less than 175 feet of Tentaculite limestone. Have a few fossils, Tentaculites, Ostracoda and a smuall Meristella, Also a Petgia near above. Most of these are in the upper thinl although the Meristella goes through. The Tentaculite is rare here and was found only in one bed about one third from the HP. This section shows with the top are the bottom, The thickness of the entire L. Id. could not be be made out but it can hardly be less than 1000 feet. L.Id. Lower are the N.J. Horizons and the Triassic zone I Part Jersey but not the Lower Potamene, This horizon does not appear to come to the