[3] They are frequently coaxial - that is they form a system in which the boundaries of adjacent fields make a series of long, roughly parallel lines.
[38][43] The widespread eviction of people from their lands resulted in the collapse of the open field system in those areas.
In parts of England where enclosure took place early (or which were never enclosed), fields are often small and have an irregular shape, sometimes described as "pocket handkerchief".
Similar stone wall field systems dating back to the Atlantic Bronze Age are visible in western Ireland and on the Aran Islands.
[6][7] The primitive ard plough used in Gaelic Ireland only scratched the surface of the soil, so cross-ploughing was necessary to break up the earth better.
The land was divided into discontinuous plots, and cultivated and occupied by a number of tenants to whom it is leased jointly.
[13] The present system of fields in Ireland dates to the 17th–18th century onwards, with enclosure of land by ditches (stone-and-sod banks) and hedgerows (made of hawthorn, beech and sycamore),[14] with a centrally located farmhouse and farmyard, being the hallmark of "improvement.
Relicts of these deserted villages and clacháns are still visible in the form of lazy beds and drystone walls.
[15] The hedgerows that divide most of the fields of Ireland are estimated to run for over 830,000 km (520,000 mi) and cover a greater land area than forests or national parks.
[16] Where early fields survive in Wales, most are associated with settlement features that indicate an Iron Age or Romano-British date.
The boundaries of earlier field systems that have fallen out of use, can sometimes be deduced by studying earthworks (lumps and bumps), cropmarks or by using geophysics.
From the mid 17th century, landowners began to commission estate maps that show the size and layout of the fields they own.