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Karen
Thomas
Head of Archive
Museum of London Archaeology
Three trenches were excavated in the basement of the now-demolished 11 and 12 Blomfield Street and rearward extensions. Natural gravels were exposed in two trenches. In the east of the site, natural deposits were cut by a series of sterile waterlain clays sloping from west-east, probably from a relatively fast flowing section of the Roman Walbrook (or a tributary of it) whose ancient alignment is echoed in the current north-south orientation of Blomfield Street.
A small fragment of Roman tegula roofing tile dated AD 50-160 was recovered from within a sandy dump deposit sealing this sequence, mortar on the broken edge suggesting reuse. To the west the sequence was repeated, with a naturally formed alluvial layer and inclusions of wood and plant suggesting formation in a semi-terrestrial environment, possibly delineating the eastern edge of the Walbrook. Again Roman pottery was recovered from overlying dump and/or reclamation layers. The earliest tentatively identified as a Roman round-bodied jar likely to be 1st century in date. A sherd of Roman natural blue-green glass was also recovered along with pottery common in London assemblages dated to the 1st-3rd centuries. This suggests that this part of the Walbrook may have been backfilled or become disused in the 2nd-3rd centuries, with dumped domestic rubbish utilised as landfill.
In the lower double basement at the back of 11 Blomfiled, 19th century brickwork was exposed immediately below the foundation slab. A floor surface and wall formed of yellow stock bricks were of similar construction and probably contemporary appearing to relate to an earlier phase of construction, and may an be a retaining wall for the metropolitan line underground built in the 1870s. The basements and foundations of 19th and 20th century buildings completed the archaeological sequence in all areas of the site.