1. Extensive grid of rectangular field parcels on land to east of St Clears between the Taf and the Cywyn rivers, extending for over 2 miles north-south by 1.5 miles east-west. The main parcels enclose around 32 hectares. The system has been subdivided with the addition of infills and smaller enclosures, but the overall grid shows evidence for a single phase of planning.

The grid may relate to Parliamentary enclosure under the 'Llangynog Inclosure Award' of 1809 (see Dyfed Historic Environment Record PRN 24427). However, the field system may be far older and could possibly be a Roman pattern of centuriation to the west of the Roman Civitas capital of Carmarthen/Moridunum (NPRN 94432). Recorded during RCAHMW aerial reconnaissance.

T. Driver, RCAHMW

2. Revised description from Ken Murphy, 2019:

'In Carmarthenshire, to the south of St Clears at Treventy, the pipeline passes through a unique field system defined by straight hedge-banks up to 4km long which divide the landscape into compartments, each covering some 700m square and further subdivided into irregular fields (Fig. 8.3). Observations made where the pipeline cut through these boundaries did not provide any dating evidence, but documentary sources suggest that Sir William Lowther, a well-known astronomer who died at Treventy in 1615, was responsible for laying out the long, straight boundaries which later 17th-century documents refer to as `the great division?, the `chief line? and `thwarte hedges?. However, it has been suggested that the large enclosures are instead a Roman land division known as centuriation (DAT website add link). A medieval enclosure lying within this regular field system was excavated at Ty'r Gate (Site 500) but was on a different alignment to the long straight hedge-banks and provides no assistance in dating them.'

T. Driver, December 2019.