III.—On the Occurrence of Beds of the Yellow Sands and Marl in the Magnesian Limestone of Durham

During an investigation of the ‘Yellow Sands’ and Magnesian Limestone of Durham and Northumberland, several lenticular and irregular hollows or caverns, containing ‘Yellow Sands’ and light yellow marl, were noticed in the Lower Brecciated Magnesian Limestone at Trow Rocks, about one mile south of the Tyne (see Map, Fig. 1).