Rocks and Romans

 

 

 

 

From Sand to Sandstone

Within the park are two large rock outcrops where sandstone is clearly exposed. These rocks were laid down as sandy sediments in the Triassic period (some 250 million years ago). Then 'Chester' was at the same latitude as the present day Sahara. The sequence is known as the Chester Pebble Beds although in Edgar's Field pebbles are rare. The sandy material was deposited by a large braided river (with numerous shifting channels) flowing through a desert landscape. It has since been compacted into the sedimentary rock sandstone typically stained red by iron oxide. Over this immense span of time Chester's location has very slowly moved north through the process of continental drift.

 

Roman Raw Material

copyright Stephen Player

Edgar's Field was once a Roman quarry. The Romans founded Chester as the legionary fortress Deva around 70AD. It was to be their largest fortress in Britain and was occupied by them until the end of the 4^th century. The vast quantity of stone needed to build the fortress walls and buildings was quarried from sites such as Edgar's Field. Local stone was used to avoid the difficulties of transporting heavy and bulky material over longer distances. The Roman quarrymen would have used wooden wedges and hammers to extract the rock. Although Edgar's Field may also have been quarried in later times (such as the Middle Ages), its origins are unmistakeably Roman because of the presence of the carved shrine to the goddess Minerva.