The limited pre-1066 holdings of the Barking Abbey nuns included a manor at Hockley. This was probably where abundant septaria were subsequently used extensively in St. Mary’s Church Hockley. The nuns held a source of these concretions from middle London clay shorelines with fisheries, salt houses etc. at Wigborough and Tollesbury on the Blackwater Estuary, downstream from the River Wid and Chelmsford.

C) Roman and Tudor Bricks at Fryerning. The Roman bricks and tiles were most easily studied in the eastern corner of the Chancel at Fryerning, where the builders had stacked them into a neat pile showing orthogonal, if sometimes obviously fractured dimensions. They were without dark internal reduction bands; unless these were all hidden. A large but fractured specimen had a thickness of 35 mm, a width of 170 mm and a length of at least 255 mm when made. Another had a thickness of 42 mm and equal dimensions of 185 mm on a square plan. According to the book Brick in Essex from the Roman Conquest to the Reformation, written and published by Pat Ryan (Chelmsford, 1996. p.159) the latter dimensions approximate to the Bessalis Roam brick variety (200x200x40 mm); but the larger one might be either a relatively thick tile (normally <35 mm thick) or one of the larger brick varieties (normally 40 to 45mm in thickness). Either way they were all thinner and less regularly placed that the red bricks presumably made at Mill Green and adjacent sites for the small early 16th century tower at the other end of Fryerning Church and the larger one at Ingatestone. Measurements taken at a corner at the Fryerning tower showed dimensions of 235 x116x52 mm, with a repeat distance of the courses of 60 mm which was still less than that seen in more modern brickworks. However, not all red bricks associated with the black and red diaper-work of these early 16th century Essex towers are so thin. The buttresses of Rockford Church tower, built for a patron who died in 1515 show dimensions of the red bricks of 238x117x61 mm and 235x115x60 mm. The showed white sand grog up to 8 mm in diameter added probably to a Pleistocene silt matrix; while the Fryerning Bricks looked relatively fine-grained.