York Historic Environment Record

In none of the trenches or boreholes was there any evidence that any fabric of the medieval church of St Mary or any of the inhumations within its graveyard survived the changes the site has undergone since these were recorded in the 1920s. All the evidence indicates that beneath the modern carpark there is nothing other than glacial till deposits. Three boreholes were successful within the existing building. The sequence recorded in these correlates well with the borehole records of 1986; laminated alluvial sand clays were present along the edge of the site closest to Foss Island Road, and the River Foss, whilst to the rear of the building, to the north-west, the ground deposits mirror those found in the car park.The alluvial sand clays were likely evidence of flooding which took place in the area after the formation of the water defences of the Norman castle and of the King’s Fishpool during the medieval period. It is unclear from the borehole records whether these alluvial deposits were from the Fishpool itself or just from the resulting widening of the river. Above the alluvial deposits there was evidence of subsequent disturbance in the alluvium, followed by past efforts to raise ground levels along this edge of the site.The presence of concrete and brick over half a metre below ground level in this area strongly suggests the survival of 19th–20th century building remains at the site, particularly fronting onto Foss Islands Road in the area of the Carpetright building. This is supported by the uncovering of a brick wall in Trench 2 that aligned well with buildings depicted on the 1852 OS map of York.