In “The Geology of the Isle of Purbeck and Weymouth” (p. 152) I referred to some green sand which occurs next below the Chalk in Mupe Bay, Dorset, as somewhat resembling Chloritio Marl, but as being too thick for that bed. As it was followed by the Gault, I concluded that it belonged to the Upper Greensand. The section was subsequently visited by Mr. W. Hill, who collected from the sand in question Holaster subglobosus, var. altus, and Echinoconus castanea among other fossils, and inferred that it was Chloritic Marl. He considered that though it passed up inseusibly into the Chalk it was faulted against the Gault, but that there had been also considerable contemporaneous erosion of the Upper Greensand. In April of this year I revisited the section in company with Mr. Hill, and was fully satisfied as to the correctness of his views. The following account has been drawn up from our observations:—

The Lower Chalk becomes extremely impure in its lower part, and contains much glauconite; it thus graduates insensibly downwards into a gritty glauconitic sand. The sand contains a few phosphatic casts, more or less worn or corroded, scattered throughout it, but has a well-marked nodule-bed crowded with these casts at its base; other fossils with the shell preserved and not filled in with phosphate occur also throughout the whole bed.