Roman London - the London wall
These pages are based on a "Royal Commission On Historical Monuments 1834" - actually it is 1928; which is in the public domain.
(37) . Newgate Prison site. On clearing the site for the New Sessions House in 1903, a considerable stretch of the wall (Plate 27), 76 feet in length, was uncovered together with an isolated fragment farther South. Above the plinth the thickness was 8 feet and the external face consisted of five courses of squared rag-stone, and a double bonding-course of brick ; above this point the face of the wall had been largely destroyed, but a second double bonding-course was visible. On the inside the facing was preserved to above the second bonding-course. The base of the plinth was 11 feet below the pavement-level of Newgate Street.
Town Wall, Newgate Prison site 1903