Bizarre ditch question time.

[Tool]

OK all you clever people, here's an odd one for you: what would I need to read to learn about profiles of ditches, the processes that can shape a ditch after it has been dug, and if there are classic shapes attributed to particular historic periods?

[John Walford]

You should have a look at the 'Experimental Earthwork Project' report, if you haven't seen it before. In brief, banks and ditchs were created on Overton Down and at Wareham in the 1960s, and then regularly observed to see how they was eroding and filling in. The results up to 1992 were published as a CBA Research Report, which can be downloaded from the ADS website.

http://archaeologydataservice.ac.uk/arch.../rr100.cfm

One limitation of the work is that it was done on chalk and gravel geologies (if I recall correctly), and so the results will be a bit different from what you would get if the ditch cut sand, or clay, or something else. But it is a good starting point for thinking about the sorts of processes that can go on.

[BAJR]

oooh I like questions like this!

come on!

[Detritus]

Hi Tool

Two books that have helped me over the years are 'Stratification for the Archaeologist' by Edward Pyddoke (1961) and 'Soils for the Archaeologist' by I.W. Cornwall (1966). They focus mainly on deposits but both have a small section on the theoretical process of filling a vertical sided ditch and how the sides are progressively eroded.

When I first started out the general rule of thumb tended to be 'U' shaped ditch=prehistoric and 'V' shaped=Roman. However this is by no means accurate; best to go off your finds assemblage.

[Dinosaur]

My experience is that whatever you read about ditch-profile vs date in the literature is generally b***ocks, varies from region to region, site to site and ditch to ditch. The same ditch can have V or U-shaped profiles within a few feet of each other, and also vary wildly in size (never forgetting extent of truncation). And remember, many ditches were dug to drain water, so what you're actually digging is water-eroded. Watch modern cattle in the landscape, they love being in the field-ditches so absolutely trash the sides - if you look at the ditches of many e.g. Iron Age enclosures (and modern fields), the outer edges of the ditches usually have a shallower profile than the inner edges, presumably cos the cattle could only get in from the outer edge (evidence for hedges?)

[Dinosaur]

...oh, and if you're on a slope, any 'cleaning slot' in the bottom is probably water erosion, lots of ditches have a continuous trickle of water that erodes out a small channel in the base - Romanists seem to have a fixation with 'cleaning slots', although wierdly I've never seen a Latin name for them in reports }

[kevin wooldridge]

I agree with Dino that trying to date ditches based on morphology is probably not good sense....even fills can be tricky cos by the nature of ditches, there is no guarantee that the fill being sampled hasn't been washed in from elsewhere rather than being intrinsic to the ditch (if that makes sense).....that said the location of ditches in the wider landscape can be of interest in defining field systems etc....however in very general terms a good ditch location in the bronze age is equally likely to be a good ditch location right through to the medieval period

[Hamish]

Interpretation is that some ditches were dug in sections by different groups (gangs) of people resulting in variations in depth and profile, sometimes particularly noticeable where sections meet.

[Dinosaur]

...there is no guarantee that the fill being sampled hasn't been washed in from elsewhere rather than being intrinsic to the ditch...

...so sampling 'ordinary' ditch fills is generally pointless - you don't know where the stuff originated from or how old it is (unless you have a discrete dump of something interesting). Stick to 'closed' contexts like (most) pits etc. Always think through the formation process before fetching the sample tubs

[Unitof1]

Iron Age enclosures (and modern fields), the outer edges of the ditches usually have a shallower profile than the inner edges, presumably cos the cattle could only get in from the outer edge (evidence for hedges?)

http://www.butser.org.uk/reuvens.pdf

basically vegetation with deep roots can stabilise the side of a ditch quite quickly and treading and grazing can reduce the stabilisation effect of vegetation and lead to rapid erosion. Add in a little north south eas and west and no two sides of a ditch are likely to be the same to start with and so suffering these different conditions makes it impossible that two sides of a ditch will end up the same. Which is why I always record/interpret mine as u shaped or v shaped with a bit of fandango on one side or the other depending on your point of view......