Having at times been asked questions about the “Fossiliferous Ironsands” of the North Downs, which Mr. Prestwich described in the Journal of the Geological Society in 1858, vol. xiv., p. 322, &c., I find that some little diagram appears to be wanted by amateur geologists and general readers for the clearer demonstration of these strata and their relations to the Chalk and the Drift.

I beg, therefore, to offer you the accompanying diagram, illustrative of the relationship of the so-called “Kentish Crag,” agreeable, I believe, to Mr. Prestwich's views of the subject, as given in his elaborate paper before mentioned. Having seen the ground at Lenham and Charing, to which Mr. Prestwich refers, and at the latter of which places my friend Mr. W. Harris, F.G.S., had some sections specially made, I feel the greater satisfaction in bearing testimony to Mr. Prestwich's careful working out of the whole question.