Thursday, July 13, 2006

June 24 2006. Continuation of reading following the visit to Ingatestone (mainly Reaney’s Place Names of Essex Cambridge University Press 1969) indicates that it is situated in that part of the East Saxon Kingdom which became Chelmsford Hundred, extending along the Roman Road from London to Braintree and Bury St. Edmunds, from the crossing of the River Wid 20 and half English miles from London, to less obviously defined wooded backcountry now termed Young’s End nearly at the 38th mile post. In other directions the hundred was not extensive, but did join the probably originally superior Rochford Hundred at the old crossings of the Crouch estuary at Hull and Battlesbridges.

Ingatestone Parish Church is one of the few situated near this route in Essex and like other exceptions is probably a late addition to East Saxon settlement which avoided Roman roads and former settlements. Later extensions of these villages around old church sites are a mile or more away on the redeveloped Roman Road and given names such as Margasetting Street, the Street in Little Waltham etc. New market towns like Chelmsford and Braintree had the original church off the road. The new Braintree church was built on the Roman settlement and directly in line with the road. It has a glacial erratic boulder incorporated into a tower built after the market opened in 1199. Widford is another church on the road. The building has apparently been even more extensively “restored”, like the rest of the exterior walls at Braintree. At Ingatestone the erratic boulder was left in the churchyard, and not reused. At the time of the Domesday Survey the name Inge was sufficient for the manors most adjacent to the stone, and the previous extended moot area given allied names later such as Mountnessing (Ginga in 1087) and Margaretting (Ginga). However, when one of the central but secular manors of Inge had a second St. Mary’s Church built on it, probably at the same time as the present c.1100 Ingatestone Church exterior, it was obviously helpful to refer to the original site where rents were paid to the nuns as Inge at the Stone. Later when King Henry II gave the other old St. Mary’s Church to Friars of Jerusalem Hospital, it became Frierning. The first known use of the name Ingatestone was therefore after the arrival of the Friars, when it was recorded as the nuns’ property Ginges ad Petram in 1254. Having gone over much of the ground himself, R. Reaney goes with Morant and the consensus and rejects the idea which he credits to the 1913 book by Wilde and Christie, linking to stone to some hypothetical Roman milestone, rather than the more conspicuous erratic stone still in the churchyard. Probably the ancient Saxons knew nothing about Roman milestones and very little about their roads, but did find the erratic a convenient marker for meetings along the old track. What has undermined this interpretation has been the previous emphasis on the erratic also being used as a milestone by the Romans. This seems highly unlikely even though their mark would have been 30 yards beyond it if they wished to indicate 25 Roman miles from London along the route surveyed for the 18th Century 22nd milestone.

Wednesday, July 12, 2006

June 20 2006. Sand sampled from around the 85 m above mean sea level in S.E. Mill Green Common, uppermost Claygate Member on the Geological Survey maps, did not look much like that Eocene marine sand, being angular with many sharp edges at 0.08 mm diameter and mixed with only few well rounded 0.14 mm grains familiar to me from the Claygates elsewhere. In addition there were varied pebbles and even an angular cobble, with the same orange sand inside their pitting and presumably moved down the hill from the mapped area of the Old Head Gravels (which should have a clay matrix). I was, however, mainly interested in what the local pebbles looked like and made the following observations:

a) Angular flint cobble. The cobble did not look like a flint to me until I broke it open to show a conchoidal fracture of dark grey (N3) to brownish grey (5YR 4/1) colour, inside a chalky cortex of typical 1.4 mm thickness. The unbroken dimensions were 97.3 by 66.0 by 48.1 mm, with a white hard vein of chert of around 9 mm width raised above the soft cortex containing a few similarly white and raised Cretaceous burrow fillings of 3 mm diameter. The exterior of the cortex did not look like chalk, or the normally much hard cortex of Chalk flints, since it was stained to a yellowish orange colour (10YR 7/6) like the sand matrix. However, in the freshly fracture the cortex was pure white chalk (N9) and not simply a white patina of the flint mineral, which according to textbooks is a microcrystalline silicon dioxide and water mineral (Chalcedony), rather than fragmented Cretaceous microplankton (coccoliths) composed of the softer mineral calcite (one form of calcium carbonate).

b) Flint pebbles. One showed the same dark grey (N4) freshly broken interior, like the cobble and flints inside the chalk mine at Grimes Graves. Others had moderate yellow brown (10YR 5/4) to orange (10YR 6/4) colour on similarly made fractures. This internal and relatively primary colouration is masked by the variable development of a white layer around the whole surface of the somewhat flattened ellipsoids, which is evidently produced by oxidation of organic inclusions in the flint, rather than by a primary cortex of chalk being preserved on this hard exterior during transportation by rivers. In a brown flint (10 YR 5/4) which had a bluish grey (5B 6/1) exterior of 44.2 x 86.6 x 24.1 mm orthogonal diameters, the white patina had a uniform thickness of 0.10 to 0.15 mm, with an underlying grey patina extending to 2 or 3 mm into the unaltered interior. Another flint found next to it had a more mottled exterior, with orange (10YR 7/6) and blue (5B 6/1) areas, and a generally thicker patina of 0.4 mm thickness extended to 0.8 mm in pipe-like structures. The interior was moderate yellow brown (10YR 5/4) to orange (10YR 6/4). A thinner patina can therefore show the interior paler colours, if present while the thicker patina can produce a dark mottling which is not indicative of how it varies in thickness over a similarly pale interior. On the surface of all these pebbles there were irregular rounded pits, which probably result from poor silicification of the parent chalk burrows and smaller triangular pits of 0.3 to 1.2 mm width produced by impact damage and or permafrost action. Between these pits there are a variety of surface cracks, generally slightly curved and with a width of 0.03 to 0.2 mm potentially made by the grinding action of the host sand. This quartz sand is slightly harder than the flint mineral and certainly less likely to shatter on impact.

c) Lithic quartzite pebbles. One sample collected as sand yielded seven of the usual flint patinated pebbles described above from various samples and three generally smaller and facetted, highly polished pebbles of quartzite. The largest of these was more irregular than triangular in shape, but with a highly polished exterior showing impact triangle of only 0.3 to 0.5 mm width, some 0.2 mm to 5 mm wide rounded pits and abrasion grooves of less than 0.02 mm width. The orthogonal dimensions were 44.8 x 23.6 x 18.0 mm and the external colour, which might be mistaken for flint, consisted of patches of darker grey (N5) in a paler grey (N7) matrix. When fractured the pebble split easily, without the flashes of flame and dangerous shards associated with splitting the flints, into a pair of parallel transverse and slightly rough cracks of similar colour (N7 and N4). There was a slight hint of greyish orange pink (5YR 7/1) on some parts of the paler fractures, Within the darker grey areas there were paler grey to white spots of 0.06 to 0.08 mm diameter, which were not sand grains, but sections through elongated objects associated with them in random orientations. They are something of a mystery without further investigation, but might be quartz pseudomorphs of the fridymite > 870° C phase of silicon dioxide, if that contact metamorphic texture was not so rare outside the North Ireland to Scotland Tertiary basaltic province. An alternative explanation is that the darker area are of trachytic of Palaeozoic lava containing elongated inclusion of glass and crystals before they cooled down. The host quartzite showed no obvious sand grains and other smaller inclusions except these 10 mm square grey clasts and a few dark 0.06 mm spots of iron oxide.

Quite apart from the different origin and provenance of these smaller pebbles, it is clear that they differ from the associated and generally more widespread flint pebbles (i.e. the latter were also seen along Mill Green Road opposite Hardings Lane and north of Mill House with a 55 mm maximum length) in being rounded and polished into facets by wind blown sand, and not by the rough sand not present around them. Ice is also required to bring them into Essex and it is not required to explain how rounded flint pebbles could be transported from say Reading, as roughly patinated ellipsoids, from the parent Chalk or Paleocene strata by a proto-Thames. However, I suspect that the softer chalk cobble and these polished quartzites actually came from the north by ice and were then polished in a dry but cold climate before being mixed with the rough sand and patinated flints.

Saturday, July 01, 2006

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.