(che)+Whitaker+and+Dalton+1887

"At and below Cheddiston (sic) the beds consist largely of gravel, and in an old pit, marked on the map, by the lane a little south-west of Cookley Grange, pinnacle of consolidated sand and gravel, cemented by carbonate of lime (probably derived from the Boulder Clay), has been left standing in land now again under cultivation. The sand is false-bedded, and the cap is of gravel, the column being 10 feet high, by 3 feet, by 6 feet."

Memoirs of the Geological Survey (England and Wales), Whitaker, W. & Dalton, W.A. (1887) //The Country around Halesworth and Harleston//.

This is the only mention made to glacial erratics in this professional geological survey within the Chediston area. It clearly refers to the 'Rockstone' in Cookley. The authors imply that a pillar was left standing when gravel was excavated from a small roadside pit. The date of working of this pit is not recorded but the first reference to Rockstone Manor is in the 13th century, implying that it was a very early excavation. We may speculate that it was associated with surfacing the lane that crosses from the valley of the Chediston Blyth to the Cookley Blyth providing a link between Cookley Grange and Sibton Abbey via Walpole.