Cropmark archaeology

Kirsty Millican HLA Officer RCAHMS

Cows, Cropmarks and a Cursus

View of Lochbrow, looking west from the cursus terminal (photo ©Kirsty Millican)

It is the kind of place most people would pass by without a second glance, an apparently empty field usually occupied only by cows, but the site of Lochbrow in Dumfries and Galloway is one of my favourite archaeological sites inScotland. My name is Kirsty Millican and I am a Historic Land-Use Assessment (HLA) Officer at RCAHMS. My interests, though, extend beyond HLA to encompass cropmark archaeology and the Neolithic and Early Bronze Age periods in Scotland. Lochbrow is a site I first encountered while undertaking research for my PhD and is a place that I have returned to several times since.

So why do I find such an apparently unremarkable location interesting? Because of the cropmarks of course! Cropmarks are formed by the differential growth of crops over buried archaeology, and are best recorded from the air. A scattering of such marks were first recorded at Lochbrow by an RCAHMS aerial survey in 1992, indicating the buried presence of pits and ditches. These features can be interpreted as a timber cursus monument (a long enclosure defined by timber posts usually dating to the Earlier Neolithic), at least one, if not two, timber circles (a monument form dating from the Later Neolithic into the Bronze Age) and several round barrows (later prehistoric monuments). This tells us that this apparently empty field was an important location for a long period of time, and was probably a hive of activity during the construction and use of these monuments.

Map of the cropmarks (in red) and the main topographic features at Lochbrow. The cursus is the long enclosure oriented north to south, the two timber circles lie to the east and south-west of the cursus and the barrows to the south.

What I have always found remarkable is the level of information such ghostly marks in crops can reveal. This is archaeology with no remaining above-ground features; if you visit the site today there is nothing to suggest such a complex of sites ever existed. Moreover, the cursus and timber circles were built of wood, a material that is not durable and so does not survive for us to study today. All that remains are the infilled pits that were dug to take the upright timbers forming the outer boundary of these wooden monuments; it is these pits that influence the formation of the cropmarks, allowing us to photograph them from the air. The cropmarks, then, give us a rare glimpse into the activities and structures built by our prehistoric ancestors. Indeed, without the simple technique of taking photographs from an aeroplane we would know nothing about this important group of monuments, nor the location of what was undoubtedly a very special place. It makes you wonder how much more is buried beneath your feet …!

So why have I chosen to visit this site several times, if there is nothing to see of this archaeology on the ground? Well, sites such as these are not built independently of their location, and you can learn a lot about a site by considering their locations, even without above-ground archaeology. Indeed, I believe that the sites at Lochbrow are closely connected with their location, and the cursus in particular seems to mimic the dominant topography. By visiting the site of these cropmarks, I’ve been able to suggest that the topography of this location was likely drawn into the use and functioning of these monuments, possibly defining the outer extents of this place, and may have had an influence upon the form of the monuments chosen to be built here. I have also returned twice (with colleagues from Edinburgh and York Universities) to undertake geophysical and topographic surveys of this site, to try to gain a better understanding of the sites here and their location, and to investigate the possibility of additional sites and features that have not been recorded by the cropmarks. The results so far are promising and I’ll be returning again later this year to finish the surveys. Who knows what we’ll find, but I’m excited by the notion that so much lies buried beneath my feet, and with a little perseverance we may be able to add a little bit more to the story of this site and to our understanding of what people did here and the structures they built thousands of years ago.

Undertaking geophysical survey at Lochbrow (photo ©Gordon Wallace)

To view more about these cropmarks, visit the RCAHMS Canmore page for this site with particular reference to the cursus and pit enclosure