From the standing-ground of what is known of London in the Middle Ages, I have endeavoured to reach back towards Londinium Augusta. To set out adequately all the data that we have for reconstructing the Roman city would require a treatise from a specialist. I can only venture here a rapid glance in conclusion at the more salient features of the ancient town. Much in recent years has been written as to a still earlier London than that included within the circuit of Roman walls which held what is now known as the City. It is at once evident that the early city must have had a nucleus and a greater density in one part than in others; and every evidence goes to show that this earliest centre was situated on the east side of the Walbrook at the head of London Bridge. We have the facts of the position of the Bridge itself, and the suitability of the site; the evidence that important buildings were densely packed in this district, while outside of it they were more and more scattered; and also that no graves have been found within this area. Mr. Roach Smith thought that certain remnants of thick walls found near Cannon Street in the south and Cornhill in the north were probably parts of earlier city walls. He says: "Here and there during excavations, walls of great thickness, which may be referred to walls of circumvallation, were intersected. The extraordinary sub-structures which were cut through in Bush Lane and Scott's Yard indicate a south-east boundary wall with a flanking tower. In Cornhill another thick wall which seemed to point towards the Bank of England was met with." Then, in a passage already referred to above, he concludes that old London Bridge pointed to the axis of this earlier Londinium, the centre or carfax of which was at the intersection of Gracechurch Street and East-Cheap. He was inclined to place the earlier north wall along the course of Cornhill and Leadenhall Street, the east wall in the direction of Billiter Street and Mark Lane, the south in the line of Thames streets, and the west on the eastern bank of the Walbrook--an irregular square with four gates, corresponding with Bridge Gate, Bishop's Gate, Ludgate, and Aldgate.[213] [Illustration: FIG. 35.--ROMAN PAVEMENT. DRAWN IN SITU BY FAIRHOLT, 1854.]