In the latter part of 1893 Mr. Albert Wallis, of Brigstock, in Northamptonshire, incidentally told me that he had found some well-known land shells in the Lincolnshire Oolite at Brigstock. The section from which these shells came I knew quite well, and Mr. Wallis was well acquainted with recent shells, so it seemed important to ascertain in what manner they found their way into the Oolitic Beds. Having talked the matter over with my friend Mr. Lionel E. Adams (Treasurer of the Conchological Society of Great Britain), we decided to go over to Brigstock, and examine the section and the shells, and arrive, if possible, at some explanation of their peculiar position. Accordingly, on June 16 of last year, we met Mr. Wallis there for the purpose indicated.