In forming the northern or City entrance on the new London Bridge, it was thought expedient to construct a Sewer of very large dimensions under the line of approach; for this purpose, on the removal of the church of St. Michael, Crooked Lane (which stood on an immemorially ancient consecrated site), a transverse section was commenced of the eminence which rises from Thames Street towards the heart of the City. This excavation was made as deep as the low-water mark, about fifty feet below the present surface of the crest of the hill. In the course of the above operation, and of preparing for the construction of the northern land arches of the new bridge, three distinct ancient lines of embankment were discovered. These successive bulwarks, by which ground was gained by degrees from the Thames for the wharfs of the port of London, are not however the object of the present communication. Careful notes of these circumstances, as indeed of all other which relate in a constructive point of view to old London Bridge and the adjoining banks of the river, have been, I know, made by the Gentleman who has already contributed some of them to the Archæologia of the Society, and who will, I trust, be induced in the same way to follow up a subject for which he has acquired such good materials, and in connexion with which he has formed such a curious collection of articles of antiquity, particularly of the Roman era.