Wednesday 23 February 2011

Trench 2

Trench 2
Trench 2 (c. 43m by 20m) was a new area of excavation positioned within the vicus to the immediate east of the eastern entrance to the fort, along Dere Street. The trench examines the northern side of Dere Street and part of the street frontage. Excavation was preceded by geomagnetic and electrical resistance surveys.

Towards the western end of the trench, a stone rectangular building was present on a north‐south alignment, approximately 4m wide and at least 12m long [23]. To the immediate north of here, elements of a small stone structure were also revealed [24]. Only the top course of the walls of these structures was revealed during this stage of the excavation.

A further stone rectangular structure was partially recorded towards the eastern end of the trench [25]. An ancillary building had been constructed onto the southern side of this [26]. A partially‐robbed wall [27] also ran along the eastern section of the excavation, the eastern face of which was obscured by the section. The lower courses of these structures were obscured by a thick dark deposit over the northeastern part of the trench, and later surfaces and rubble to the south. However, excavation of a later ditch cutting through the western wall of structure 25 revealed at least five courses surviving (0.6mhigh). Breaks in the upper course of the southern wall of structure 25 and the western wall of structure 26 may be indicative of the base of the windows. Plaster survives in situ on the wall faces of structure

Contiguous with the top of these walls, spreading across much of the northern part of the trench, were surfaces comprising various elements, including cobbles, paving slabs, mortar and rubble. These may be indicative of the use of the area at this level, perhaps in conjunction with several stone‐lined pits and sunken areas, two of which are shown on the plan. These features include flat slabs in their construction, and are similar to those identified in Trench 1. Over these surfaces and covering much of the northern part of the trench was a dark deposit of soil in which large quantities of animal bone, including significant quantities of cattle skulls, was present – as in Trench 1.

Across the southern part of the trench road surfaces were present, comprising cobbles and gravels, reflecting different surfacing episodes. These were over the line of Dere Street and are likely to reflect a later use of the street as a surface in the post‐medieval period. This was demarcated on the northern side by a smaller sunken track, curving across the trench, in which wheel ruts were visible. Parallel with the line of Dere Street and further to the north, a ditch ran across the trench. The northern edge of the trench cut into the edge of a soil bank running parallel with this ditch. It is likely that all these features relate to the medieval and post‐medieval landscaping of the area, the bank marking the edge of the ploughed area to the north. Other features in the trench currently under investigation may also relate to this phase and to the robbing of earlier stone walls.

Interim Report: Trench 1

We are making good progress with compiling the interim report from our 2010 excavation series. We should have this completed by Easter. In the mean time here is the site description of Trench 1 and the associated plan

Trench 1
This was c. 37m by 26m and located in the north‐east corner of the fort. The excavation was begun in 2009, and continued in 2010, when a 15m by 5m hand‐dug extension was added to the south‐western corner.

Along the south‐eastern edge of the excavation, the interior of the earlier fort rampart was exposed [1]. A stone and clay oven was partially excavated, which had been constructed into the rampart [2]. Built over this oven and against the early rampart was a second rampart, running along the northern edge of the excavation trench, and forming the northern edge of the later fort [3]. This incorporated a wider corner area [4], within which a corner tower had been constructed [5]. Of similar construction to the later rampart, and perhaps constructed at the same time, a large raised area was built against the early rampart in the south‐eastern corner of the trench, sloping down towards the centre of the fort [6]. Stone walling on both ramparts may have supported angle towers [7, 8].

A long narrow rectangular building ran parallel with the south‐east rampart, set back c. 14m from the rampart edge, and c. 6m from the north‐east rampart. The building, as exposed, is c. 30m long, and c.6m wide internally. The stone walls [c. 0.6m wide] are generally faced on both sides, with a narrow rubble core, although there are variations in construction which may indicate different phases of building, and their association with exterior stone surfaces. Up to three courses of wall were visible in places, including wider foundation courses: at the southern end of the western wall in particular, larger stone blocks set in clay may indicate an earlier building on the same alignment, reused as a foundation for the later building. The wall foundation appears to have been extended further south in this area through the construction of a bank of clay and stone [9].

Possible post holes were identified within the upper surfaces on the walls which may be indicative of a timber superstructure. Elements of internal stone walls were present within the structure. Across the centre of the building was a surface of large paving stones [10], into which a deep stone and clay‐lined pit had been incorporated [11]: a cattle skull had been placed in the base of this pit. A hollow way [12] led towards this from a probable entrance in the north wall of the building. This cut through a clay floor, over which elements of paving and gravel surfaces survived. A drain, lined with stone roof tiles, had been constructed across this floor [13].

To the south of the paved surface was a sunken area [14], up to 0.5m deep, demarcated by the walls of the building, internal paving, and an internal wall. Further paving was present in discrete areas within the building to the south of here. Elements of clay floor also survived within this area.

Built against the eastern wall of the building were stone and cobbled surfaces (15), stretching towards the eastern rampart. These surfaces appeared contiguous with the upper surface of the wall, but did not extend within the building. They extended over the raised area in the south‐eastern corner of the trench, and around the southern end of the building, demarcating the extent of the building in this direction in this phase of use. Elements of stone surfaces were recorded to the north of the building, but the surface was not contiguous in this area. The surfaces spread over and incorporated the remains
of a second rectangular stone building (16) positioned over the raised area, which was off‐alignment with the fort ramparts.

Incorporated within the surfaces were two linear gullies [17], which may be associated with crudely constructed low stone banks [18]. Stone banks were also present along the top of the northern rampart and along the edge of the south‐eastern raised area (partially remove in 2009). Stone‐lined pits were present within the surfaces; two of the larger of these are marked on the plan [19]. These are partially lined with flat stone slabs. Further similar features may be present at the eastern edge of the cobbled area.

The cobbled surfaces were not identified on the western side of the building. Here, a clay and stone path led up over the wall of the building [20]. Elements of two stone‐lined pits with associated stone spreads and low banks were recorded in this area [21]. Large quantities of cattle bone were recovered from this area of the site in particular.

An antiquarian trench was identified through the angle tower [22]; some of the facing stones for the walls had been removed. Deposits identified across the trench that related to post‐medieval landscaping activity and ploughing were excavated in 2009.

Wednesday 2 February 2011

Roman kilns

A post from Melissa Chatfield on our plans for this summer at Binchester

"One of the ongoing research agendas with the Stanford group is Binchester Kiln Project. Initially funded by the Stanford President’s Fund for Innovation in the Humanities, the project set out to make a replica Romano-British kiln on campus as a practice run for a similar kiln to be built on site in England. Ideally, we will make a pottery kiln that is an exact duplicate of one that we find at Binchester. Based on the results of the geophysical survey, it is likely we will find one this summer. In the meantime, we constructed a kiln on campus that is a composite of several key features found in Late Iron Age and early Roman kilns of Britain.

In mid-January, we fired our Stanford Binchester Kiln for 19.5 hours to bake about 40 pots, which were made by the Ceramics Club and the student-run Ceramics studio on campus. Over this period, we weighed wood in a bucket suspended from a ladder and took temperature readings using a digital data logger with 3 thermocouples: two positioned in the ware chamber and one between the layers of sod over the fire tunnel.

Using a mixture of hard woods and wood from fruit trees, we sustained a high temperature of about 950ยบ Celsius that was achieved about 15 hours after ignition. Students and volunteers stayed late into the night, and a few into the early morning as the dew began to settle on our grassy kiln

We let the kiln cool for about 30 hours before opening it up. The sod covering the ware chamber cracked and crumbled in our hands. All of the 40 pots survived, although some had experienced some heat warping. The wall of the kiln, with no clay lining other than the clay matrix of the mound, sustained some cracking but no spalling, which was good for the pots. However, these cracks might need to be repaired before our next firing.

A few of the pots in the mix, such as the orange one in the foreground of the photo on the right, were made with clay we shipped back from a clay mine near Binchester. As luck would have it, the world’s largest brick manufacturer, Wienerberger, has a brick factory about a mile from the site and has been an enthusiastic supporter of the kiln project. Taking the lessons we learned from our experience at Stanford, we will design and build our Durham Binchester Kiln over the next few field seasons. With access to all the geologic strata of clay in the region, including the clay available in prehistory, we will continue our experimental work in the acquisition and transmission of craft knowledge.

For more information about the construction process of this kiln and continuing research, please visit the Burnt Earth Blog .