The purpose of rows

To put the surveys hypothesis on a firmer footing, we need to explain how building a row might benefit a survey. We have noted that the alignment originating from a straight row section is remarkably precise. Assuming that precision was one of the key reasons why rows were laid, we need to explain how that precision may have been used.

Our suggestion is that rows were used in conjunction with another survey method to lay out lines across the landscape. The use of a row enabled a more accurate line than the other method alone. An obvious candidate for the partner method is the one that uses poles to mark out a straight line over hills. The only tool required is a set of tall poles. The method is still taught today (e.g., Brouwer 1985, section 2.3.3.) but it is thought to be very old. Indeed, it has been suggested before that the Long Man of Wilmington hill figure (Sussex) represents a surveyor holding two such poles. The image is thought to date from the Neolithic.

We think that many of the rows on slopes were used to accurately lay lines through locations where it was difficult to use poles, and/or using poles alone was deemed too inaccurate. Laying a row enabled two surveyors who were in sight of one another to drop the line between them into a location only one of them could see.

The diagram illustrates one scenario where a row would be useful:

Once a row had been laid, it could be exploited to set more lines, sometimes towards distant landmarks. The same landscape challenges that caused the first row to be laid, often demanded that a further row section be laid. That is why we find two row sections of different orientation joined end to end, converging on the same point or crossing one another.

There are also situations where a row was used to set out the direction of a new survey line on relatively flat land. The evidence for this, found at a row on Bodmin Moor, is explained in the ‘Links between Stone Rows, Banks and Stone Circles’ section. We mention it here, because a few Dartmoor rows are of a similar design to the Bodmin row and so probably served that purpose.

We are also confident that the Dartmoor megalithic rows can be explained as survey tools.

DESIGN OF A SPECIFIC STONE ROW

Our exploration to date suggests that the Dartmoor rows were expertly designed. If so, we should be able to explain for the better-preserved rows, in purely pragmatic terms, the builder’s choice of stone size, stone spacing, row length, number of stone lines (single, double, or triple), and why some stones are significantly larger than the others in their row. We have already done this in outline for some rows but the work needs consolidating ahead of publication.

We can then deduce a plausible set of decisions and actions that the surveyors may have taken when building a specific row. The decisions and actions need to reflect the design of the surviving row, the constraints imposed by the surrounding landscape and an assumed, plausible, local surveying objective. We hope by so doing, to fully interpret the surviving row and to demonstrate how surveyors may have thought and worked 5000 years ago.

Further research

We also hope to consolidate our interim result that 75%-80% of Dartmoor row sections plausibly align on a natural landmark or a large barrow. However, our own methodology is labour intensive. We are therefore hoping that someone who is more accomplished in GIS skills than us, will be able to automate the exercise and confirm our result and with greater accuracy and confidence!

When viewed from the survey hypothesis perspective, the Dartmoor megalithic rows also yield hints as to their age and purpose. They also show similarities with megalithic rows in other regions. This work needs taking further and then consolidated before publication.