Comparison of Rayleigh and Eastwood Churches

December 22 2006. Measure all the London Clay concretions seen in the exterior of St. Lawrence and All Saints Church, Eastwood in Essex for comparison with Prittlewell Priory who held it as a chapel from about 1110 to the establishment of a rector in 1248. Probably this means that the Cluniacs were given what is now the Norman Nave built a few years earlier and that no further work was done with the tithes until the independent rector added the present Tower, Chancel and South Aisle walls, described as early 13th Century in architectural guidebooks. There are some later walls and an entirely red brick 16th Century South Porch which contain no London Clay materials; the bricks probably being made for sands and flint gravels of the second terrace mapped by the Geological Survey around the brook 0.3 to 1.1 km west of the church. These bricks have a similar colour on fresh faces (10R 6/6) to those made from well sorted coarse silts and very find sands of the Eocene Claygate Member in the Rayleigh South Porch, but contain obvious white and black pebbles in old bricks of dimensions 214 mm by 105 mm by 57 to 62 mm. Associated finer-grained bricks with dimensions 226 mm by 105 mm by 47 mm also have Pleistocene-derived flints in them. The Rayleigh South Porch is said to date from just before 1497 and has a granule-grade grog consisting of iron oxide concretions, yellow laminated sand clasts and similar sandy clay flakes; all of which could have come from the Claygate Member of the London Clay exposed around Rayleigh Church and Castle. The average and more uniform brick dimensions in that porch are 218 mm by 116mm by 58.5 mm. Previously measured Rochford Church tower bricks of similar age averaged 233 mm by 116 mm by 58.5 mm, and are derived from Pleistocene silts and sands in the Rochford Buried Channel under both Rochford and Eastwood Churches. At Rochford the coarse particles or grog included by the brickmakers consists of white and grey sandy clasts of dimensions 6 mm by 5 mm presumably made from calcareous concretions or previously dried silts of Pleistocene age. The Rochford tower was built for the grandfather of Anne Boleyn who died in 1515 and unlike the Eastwood and Rayleigh Churches his brickmakers made additional black bricks of similar size to produce diapers on the red brick tower. At Rayleigh this pattern was made in or shortly after 1515 by placing black flints among the Kentish Ragstones and septaria of the Alen Chapel, east chancel wall and some buttresses. It was not attempted in the South Porch probably because it was built before that fashion had developed and it was attempted at Eastwood.

Turning now to the London Clay concretions there is just one seen in the largely hidden walls of the Norman Nave. Since it contains no thick veins on the original exterior and differs in colour from those in the 13th Century walls it may perhaps be regarded as a questionable septarian record. The average colour measured from three parts of it in the freezing fog is 5.0YR 3.67/3.33 and in a previous visit in the bright afternoon weather of October 3 2005 it averaged 6.67 YR 4.00/3.33. Two parts of it were recorded as dark yellowish orange (10YR 6/6) and blackish red (5R 2/2) in both weather conditions by holding the Rock Colour Chart colours in the same light as the wall enveloped by the grey background cardboard of the chart. A third area of the concretion was recorded as Greyish Red (5R 4.2) in the sunshine and as the reddish brown (10R 3.2) today. With more experience I think that this concretion is from the London Clay, probably from Southend, and matches the red variety seen in Leigh Church tower, the Norman walls at South Church and Sutton churches and some of the Prittlewell Priory and Rayleigh Church septaria. By contrast the London Clay concretions in the Chancel and South Aisle at Eastwood are of a different colour and provinance with an average colour of their matrix measured today from 8 fragments and 24 areas of colour as 7.708 YR 6.208/3.33, changing to 7.692 6.269/3.341 with the addition of two vein colours seen on one of them (marginal prisms 5Y 8/1, central prisms of upsplit 4 mm thick vein 10 YR 6/6). Bearing in mind how small and scarce these concretion fragments were one should not assume that they do not come from thicker veined concretions seen at Southend, or were not bored by modern beach organisms. On December 14 and 18 I revisited Rayleigh Church and recorded all the colours on the London Clay concretions in the lower external wall of the most eastern of the four bays in the South Aisle, and also in what appears to be a later wall built around the post-1394 Ragstone tower forming a thicker west wall of the western bay to the South Aisle. The eastern bay include previously fallen concretion fragments showing Eocene high spired microgastropods (perhaps Litopia sp. or Spiratella tutulina (curry) and the west wall shows some calcite replaced wood with bivalve borings of Eocene age in it (3 mm diameter Teredolites longissimus Kelly and Bromley. The claystone matrix of the fallen fragments, of both grey unweathered and red veined lithology is full of coarse silt and very fine sand in a bioturbated clay matrix. The veins all have a pale yellow prismatic margin, followed by dark orange as at Eastwood, and then when thick enough another pale layer of open scalecohedral calcite prisms with a dark surface on the open vein. In one case this dark manganiferous oxide layer was overgrown by a 20 mm diameter rostette of white barite fibers, as at Prittlewell Priory. In terms of the average colours of the matrix and jointing in the western wall of the South Aisle was 2.22 Y 6.833/2.500 (18 determinations), the new insitu measurements of east bay 8.65 YR 6.294/3.024 (85 determinations) and the December 4 Choir Vestry 10.0 YR 6.229/3.057 (35 determinations). They all show the same sequence of veins and I do not doubt that all these walls were built from the same concretions, probably present on the site and perhaps left institu in the east bay wall when the church was repaired and extended in 1394. The sequence of vein cements is most characteristic at Rayleigh and obviously produced a variable average vein colour there recorded as follows: west wall (5) 9.00 YR 6.200/4.800. East Bay (20) 0.30Y 6.100/2.900, choir vestry (4), 2.50Y 7.500/3.000. This was an exposure of highly disturbed brown London Clay with similar thick-veined septaria of grey to brownish red colour on the upper beach about 110 metres east of Crowstone Avenue on December 20th and I intend to compare the samples to these similar-looking Rayleigh and Eastwood Church septaria over the holiday when dried.

Rock colours at Prittlewell Priory

December 13 2006. Visited Prittlewell Cluniac Priory to check similarities between the septarian London Clay concretions formerly exposed in the foundations of the south transept of the Priory Church and those in the south aisle at Rayleigh Church potentially built before a rector was established there in 1314. Before that the Cluniacs of Prittlewell potentially had some involvement in Rayleigh Church. Around 1164 Thomas Beckett gave them some control over the Milton manor, (now Westcliff-on-sea and eastern Southend) which was held by the monks of Canterbury for their own supplies since 959 (Canterbury continuously Southchurch, presumably the coast east of the pier continuously since 823). The supplies doubtless included division D and perhaps E London Clay septaria used to rebuild the priory church in stone at the end of the 12th Century, after it was founded with no control over the coastal manors around 1110. This priory was dissolved in 1536. Since little local church building took place after that reformation until the Victorian era it is unlikely that any of the stones from the partly demolished priory can now be seen off the site. There is, however, an old, but post-1536 vintage wall showing the priory septaria in similar weathering conditions, on the north side of the cloister. Today I measured a north facing patch of these septaria and one or two in the cross-section of the wall using the Geological Society of America Rock Colour chart as at Rayleigh, Hadleigh, Broomfield etc. A patch if relatively wet and lichen-covered foundations near where the Chapter House passage would be in a monastery cloister (i.e. S.E.) was also measured and added to previous data from the now covered South Transept near the new wall (i.e.N.E.). The septarian veins were up to 11 mm thick and composed of prismatic calcite of variable lightness value and much less chroma than either the calcitic matrix of the host concretion margins or of the similarly thick and banded veins at Rayleigh. They do in fact match the scare septaria in the east nave at Hadleigh much better than the Rayleigh septaria and require a separate analysis of vein and matrix colours during averaging. Often there are hardly any vein surface colours to be seen in a church and their inclusion makes little difference to the average dominated by ferruginous sepatarian joint surfaces, weathered exteriors showing Eocene burrows and modern marine borings by Polydora and internal exfoliated calcite claystones. This is the case in the new and rather wet Chapter House passage concretions which averaged 7.576 YR 5.485/3.273 in a set of 33 colour determinations from all the orange concretions there. The undivided data from the new wall averaged 7.754 YR 6.217/3.174; with the lightness value 6.217 increased by factors such as drying and lack of lichen to the condition seen in church walls and dried polished sections. The chroma saturation of 3.174 is slightly less because the new wall contains a more varied sample of the concretions from the priory, and the hue is shifted from red to yellow because of them and the inclusion of the calcite veins in the data set (69 determinations).
It needs to be explained that hues re averaged by imagining that the yellow-red (YR) scale continues through all the hues in a manner that produces small then negative numbers in red haematitic oxidation surfaces (i.e. -5 for hue 5.0 R) and large positive numbers for reduced iron purple-blue colours (i.e. +65 for 5.0 PB). Since most of the concretions are brownish the average is in the YR scale; but it can shift into the yellow scale Y when the matrix is a largely unweathered olive grey colour and pure calcite vein surfaces are exposed. Hues reported as such and such Y should have ten added to them when plotted or compared with averages still in the zero to ten Yellow-Red scale.
Vein surface measurements exclude the barite rostettes in the middle of the septarian cracks, which provide important provinance, clues. In the South Transept sea-worn and Polydora orange (10YR 6/6) concretions had rostette diameters of 20 mm, compared to 22 mm for the one in a similar matrix in the South Aisle Rayleigh. However, the averaged vein colours in all the determinations from the Priory site are much closer to Hadleigh and showed no more barite today.

Hadleigh E Nave veins (2) 2.50 Y 7.50/3.00

Hadleigh E Nave matrix (14) 6.4 3 YR 5.57/3.57

Priory x wall veins (21) 1.905 Y 6.33/2.38

Priory x wall matrix (93) 6.720 YR 5.96/3.56

Rayleigh Choir Vestry veins (4) 1.125Y 5.57/2.75

Bivalve Borings at Rayleigh Church

December 4 2006. Visited Holy trinity Church in Rayleigh, Essex to buy Christmas cards sold to fund restoration of the building by registered charity 1069853. Also determined more colours on the London Clay Formation calcite concretions there, giving 46 determinations from the relatively old South Aisle (averaging the yellowish grey 1.74Y 5.76/2.96 in Munsell system) and the younger walls of the early 16th Century porch, buttress and flint diapers, plus a north-west extension which is presumably of 18th or 19th Century age. These younger wall concretions average another yellowish grey 0.12Y 6.18/3.02 and look like a less exfoliated version of heterogeneous concretions seen in the South Aisle. Perhaps this is because parts of the old walls from inside the church were reused in these relatively small extensions. Both parts show poorly veined and numerically dominant concretions bored by the modern marine worm Polydora Ciliata Johnston (as at Broomfield Church reviewed earlier). Polydora is more conspicuous in the relatively unexfoliated concretions between the early 16th Century red bricks of the porch and buttresses. A South Aisle concretion, fallen from a decayed part of the wall not yet renovated, showed Polydora borings of 1.5 mm U-tube diameter and 12 mm length extending from a poorly veined joint which was once open on a foreshore or subtidal wavecut platform. What appeared at first sight to be holes left by missing pebbles proved to be modern bivalve borings of 18 mm length and at least 45 mm length. These showed concentric ridges transverse to their axis. These are not seen when pebbles are removed from a soft rock or concrete. In addition, there were a modern bryozoa, presumably Membanipora, grown inside of the bivalve cavity. The sequence of events evidently started with the exposure of a wavecut platform of the London Clay Formation with a band of the subhorizontal calcite concretions worn into a pitted surface rather than the raised Eocene silt burrow fillings of radial Glockeria (seen in porch) and 1.5 mm diameter shafts and polygons (seen in all later walls). The septarian cracks, which were probably not thickly veined in the bored concretions at Rayleigh, became open and calcite-free surfaces extending as an escarpment of the platform with both Polydora worms and probably Burnea bivalves boring horizontally into the stone with a generally uniform weathered colour determined dry as the typical greyish orange 10YR 7/4 seen in churches. the similarity of the colour on the horizontal exterior, previously protected by mortar in the wall, contrasts with a local region of the bored vertical crack showing evidence of reduction of oxygen in the form of a 4 mm thick layer of pale blue 5 PB 7/2 showing no deflection around the Polydora borings passing through it. Since the bivalves had died and had their homes slightly encrusted by bryozoa before the concretion was collected, it is likely that it was displaced by the sea into a muddy foreshore before it was picked up. Probably the original site was a lower foreshore channel with dangerous riptides and the collection site was an adjacent muddy beach. This setting would match The Street at Whitstable today but there may have been similar environments in Essex in Roman, Saxon or perhaps later times before the South Aisle was built (presumably in 13th Century) but from an older church materials still being used for the buttresses etc. in c 1510 and later extensions. This brief reconstruction does not refer to the other type of London Clay concretion present in the South Aisle and new N.E. corner, except as part of the average colours. These clearly came from the Upper London clay, most probably in division D at Southend, rather than division E in the Rayleigh brick and tile excavations of post-1400 vintage. They show thicker sepatarian veins with coarse prisms of ferroan calcite including a dark yellowish orange (10YR 6/6) layer flanked by less chroma, and forming a rough surface in the middle of the cracks that in one case shows small rostettes of barite (barium sulphate) of the size seen at beach level where the coast bends between Westcliff and Chalkwell. What is less clear is whether these true septaria if the upper London Clay came from the same source as the bored concretions at Rayleigh described above. There is no actual proof of middle London Clay fossils in Rayleigh, although there is at Prittlewell and Rochford Churches in the less thickly varied material. Glockeria is seen both in division D at Chalkwell and division B in Essex, and they apparently thin-veined bored concretion noted above may just have come from the tip of a large tabular one in which the full thickness of the calcite veins is not developed. Certainly many of the Rayleigh concretions with a drab and smooth exteriors are just parts of the thickly veined ones, with a coarse silt matrix more typical of burrow-fillings in division D or E than the Glockeria and crinoid concretions of division B. The extent to which the average colour reflects a mixture of two different provinances is unclear in this more complex church building.

Leaf fall and strandings at Southend

November 27, 2006. After a windy week and previous night Chalkwell beach showed a gravel ridge formed in front of a strandline of algae and diverse deciduous leaves. They included a greenish yellow leaf of the Hawthorne Crataegus monogyna Jacquin, shed by one tree in my garden from November 14 to 18 this year, and from the same tree in 1997 from November 7 to 16. Smaller Hawthorn trees and hedges still retained many yellow leaves today and in previous years (1996 and 2005) they only started to fall on December 1st and had gone within a week. Static floatation tests on the December 2000 insitu and fallen Hawthorne leaves yielded average times of 0.6 and 0.7 days, little more than one tidal cycle duration and a maximum time in a sample of 59 of 2.40 days. In the rough sea environment there is probably a long enough flotation time for these and many other deciduous leaves to cross the Thames from the opposite Kent coast (6 km) when the wind is from that southerly direction. However Oak and some evergreen leaves (i.e. Holly, Ivy) can float for over a week in tests and can come from a greater distance down the River Thames and other estuaries before being sunk or stranded. These leaves are seen in smaller numbers on strandlines throughout the year, usually after rain and in the case of evergreens, probably because of dumping of garden waste in the Thames.

A diverse leaf assemblage was studied at Chalkwell on November 28 2003 by collecting a mass of stranded algae and picking all the leaves out of it. The 57 leaves included 14 oak (12 Quercus robur L. and 2 of the local forest species Q. petraea (Mattuschka) and 30 serrated elongated leaves which may have included the other local forest tree Hornbeam Carpinus betulus L. In addition, there were 3 leaves of Poplar (Populus) which probably came from a tree near the beach, 2 or 3 Maple (Acer campestre L. and single leaves of Willow (Salix) and Horsechesnut (Aesculus). These three are common ornamental and street trees in Southend-on-Sea but seemed unlikely to have been blown into the sea from these more distant trees by the gentle south and west winds developed on the night of November 27/28 2003. Maple, Horsechesnut and a Sycamore (or Plane Tree?) leaves were observed in the strandline today and seem unlikely to have come directly from the land into stronger onshore wind.

The question of whether these leaf fall and stranding observations illuminate global warming is problematical since the botany textbooks relate the change in colour and strength of the leaves to reduced day length not temperature (i.e. via the plant hormone auxin). Looking at the common Southend street trees today (Aescules) there was evidence of still green leaves on branches of otherwise bare trees adjacent to streetlights. On the other hand, there were many entirely bare trees situated beside the lights and some retaining some leaves further away. None of the trees, except those suffering from a new disease in Horsechesnut had lost leaves on November 4, although many were partly yellow and brown by that date. Probably temperature and previous dehydration has an effect additional to that due to day length, but it is difficult to make general observations.