Excavation

Responsibilities

Excavations this summer will focus upon Area K (Palazzo Imperiale) and Area D (Navalia). Each of you will be allocated to work in one of up to seven distinct “trenches” at the start of the Field School. Each of these trenches will be overseen by a supervisor who will guide you in the process of excavation. You will be responsible to him/her, and they in their turn will be responsible to the Fabrizio Felici (Excavation Manager) and Roberta Cascino (Documentation Coordinator and coordinator of Italian students); they in turn will be responsible to the Simon Keay (Site Director). Dragana Mladenovic (Field School Director) will ensure that you are fulfilling and learning from all the different activities outlined below. You will also periodically be visited by other staff, including Steve Kay (Topography), Penny Copeland (Finds), Hembo Pagi (photography) in the course of their duties across the site.

The Process of Excavation

Excavation involves the uncovering, definition, recording and removal of a complex sequence of features that represent different activities in the life of the site. In the case of Portus, these include very substantial brick-faced concrete (opus caementicium) walls and vaults, concrete and brick (opus spicatum) floors, earth fills, spreads of collapsed construction debris, mosaic floors and human burials. These are all excavated in the reverse order in which they were created. In other words, the latest features are excavated first because they were created last, and followed by those that were laid down before them. The excavation is geared towards understanding the spatial relationship between all of the features that are excavated as well as their place in an overall site sequence that runs from latest to earliest. These relationships are expressed in what is called a site matrix.

Features are dated in relative terms by their position in the matrix, and in absolute terms by the ceramics, coins and other finds found within them – usually expressed as a terminus post quem (time after which) or terminus ante quem (time before which).

Photocopies of different approaches to excavation are maintained in the Casale.

The tools that you will use will include on the excavation trowel, brush, scraper, spade, shovel, large pick or mattock, handpick, wheelbarrow, bucket. Your supervisor will show you when each of them should be used, and how to handle them.

At Portus, the range and sequence of activities involved in the excavation of an individual feature, or suite of connected features, can be summarized in the following way:

1. Surface Clearance. Initial clearance of the area for excavation can either be done with a machine or by hand using picks, mattocks and shovels. The general idea is to remove the topsoil that lies on top of the archaeological surface below. This is done by working from one site of opened area to the other to the appropriate depth (the supervisor or Fabrizio will help here), working systematically, frequently shovelling the soil and rubble into wheelbarrows close to the side of the trench.
2. The exposed archaeological surface is then cleaned with shovels and brushes, so that the preliminary identification of features, such as walls, floors, drains, piers, ditches and burials can take place.
3. Once these have been noted, they need to be assigned context numbers. These context numbers are assigned by Fabrizio, and they are marked with a label fixed into it with a nail.
4. There then follows the preliminary recording of the exposed and numbered features with assistance of trench supervisor. Each of the features is further cleaned so that the limits of them are visible; they are usually distinguished from the surrounding soil by colour, dampness, hardness or consistency. They are then planned in a process whereby the edges and surface details are drawn and labelled in pencil on a measured and scaled plan on permatrace (affixed to a drawing board) – and then subsequently digitized. Then the height of the feature relative to the site datum is then recorded with the site total station by Steve Kay: depending on the size of the feature, he can also take several points to locate the position of the plan. These are later fed into the site Geographical Information System (GIS). Lastly, details about the context are recorded on the context sheet, and can be updated as excavation proceeds.
5. There then follows the excavation of the numbered features with trowels, hand-picks, buckets etc, as appropriate: the supervisor will advise how to proceed and when this is complete. If the feature is a wall, this will be when its structure is fully revealed. If it is a fill of soil within a room, this will be when all trace of the soil has been removed and the underlying layers or floor, usually of a different colour or texture, is revealed. If it is a burial, this will be when the bottom of the grave has been reached.
6. During this process of excavation, all the ceramics, animal bone, metal work etc. encountered will be collected and put into a finds tray. This is kept very close to the trench and has in it a ticket with the number of the feature that you are excavating: check with your supervisor that this is the correct number. Place the ceramics, stone and marblein one tray, and the very small ceramic sherds, tesserae, animal bones, shells, metals, glass and stucco etc. in another tray. Special, or “small” finds, such as coins, beads, metal objects etc. should be individually bagged (see chapter 5 of the handbook for details of finds and proceedures). Trays of ceramics etc. should go on the shelves close to the excavation and bagged finds should be taken to the Casale when the excavation finishes at 5.30pm.
7. There will also usually be a collection of a sample of soil from each exposed feature for environmental analysis: the supervisor will advise when and how this has to be done. The sample should be placed inside a clean plastic bag, which should have one label with context number written in permanent marker inside the bag and one tied to the outside. The point from which the sample was taken will be recorded by Steve Kay using the Total Station.
8. Once the feature has been removed through excavation, a measured and scaled plan and section is normally drawn. The supervisor will advise this has to be done. It is usually drawn and labelled in pencil on permatrace fixed to a wooden board. Sometimes a section created by removal of half the feature may also be drawn, because this provides a record of the excavated fill.
9. The levels of the of the bottom of the feature excavated are then taken by S. Kay in conjunction with you/other.
10. The feature is then photographed by an appropriate person. The supervisor, Fabrizio or Roberta will tell you when this is done, but it is usually when the excavation of the feature is complete – and the light is right. The photo will either be taken by the supervisor in conjunction with those of you in the trench in the same trench, or by Hembo Pagi. The photograph is intended to complement the plan and section of the feature. There should always be a photographic scale or ranging rod (depending on the size of the feature[s]) in the photo, together with a small blackboard, on which will be written the feature number, and a site north sign. At the end of the day, all site photographs taken should be entered in the site photo register. Your supervisor, Hembo or another senior member of staff, can help you here.
11. Once the excavation of a trench has finished, a record of the levels excavated can often be found in the side of the trench, and provides a very useful record of the sequence of activities in the trench. As such it is a very valuable complement to the plans and photographs. These are also drawn and photographed, and their position located with the total station.
12. Excavation will probably expose standing building remains which will need to photographed and recorded as part of the process. See chapter 4 on Standing Buildings for identification of types of wall structures.

Safety Tips

When undertaking excavation it is important to remember that you should always wear a helmet. This may be uncomfortable initially, but you will get used to it.

You should ensure that tools are not left lying around on the ground in the area being excavated since they can cause a trip hazard. This is particularly true of spades, shovels and similar tools which can flick up and hit you if left on the ground, causing hurt. When not being used they should be propped up against the side of the excavation or somewhere out of the way outside the excavated area. When using the pick or shovel, make sure that the area is clear and there is no one nearby who can be hit by them. It is also a good idea to wear goggles when picking since stone chips can fly into your eyes. When trowelling, scraping and brushing a dusty surface make sure that you wear goggles and a mask to avoid the irritant of the dust.

You should NEVER walk on any of the walls for any reason as they can be unstable: this is particularly true of Area K. There are areas cordoned off because they are unsafe so be safe and keep away from them. Do NOT stand close (less than 30cm/1ft) from the edge of a trench as this can promote collapse on the people working below or destroy their hard work. This also applies to sitting on the edge of the trench!

Do not lift heavy items such as stones, lumps of masonry or tree roots unless instructed to do so by the supervisor or a senior member of staff, who will see whether this is possible, and if so, how you should approach the tasks.

When using a wheelbarrow, keep it awayfrom the edge of the trench or it may fall in, collapse the section etc. Do not fill it too full and do not attempt to run with an overly full barrow to the spoil heap or you may lose control.