9
A SARSEN BOULDER GRAVESTONE AT DEDHAM, ESSEX
Adjacent to the middle buttress of the south aisle at St. Mary's Church Dedham is a pale
sarsen boulder gravestone. This stone which is at least 66cm high, 42cm wide and 31cm
deep is a tertiary 'sarsen' (silica-cemented sandstone). Although not on the same scale as
the sarsens used in the well known Bronze Age monuments at Stonehenge and Avebury
this humble Essex boulder has its own interesting story.
Nearly 60,000,000 years ago fluvial sand deposits of the Reading and Woolwich
Formations (Lambeth Group) were laid down over much of southern England. About
20,000,000 years ago, during early Neogene (Miocene) times, silica was precipitated just
below an arid land surface and cemented patches of this sand (Sumbler 1996 pp.106-
107). Subsequently, during the Anglian Glaciation some 470,000 years ago, southward
moving ice-sheets eroded the ground over which they passed and deposited this stone and
other erratics at their bases or dumped them when the ice melted as boulder clay (Sumbler
1996 p.118). A comprehensive suite of enatics, including sarsens up to 2m in diameter,
was observed during the official geological survey of the Braintree area (Ellison & Lake
1986 p.35).
Although boulder clay is not exposed in the vicinity of Dedham churchyard it does occur
about 3 kilometres to the north at Holton St. Mary, Suffolk and nearly 10 miles to the
west at Little Horkesley, Essex. The geology of the Dedham area is river gravel overlying
"London Clay" (Whitaker 1885 pp.17-18, 106). A map showing the location of sarsens in
this area, including several near Dedham, was published by Boswell in 1925 (Boswell
1925 fig. 1). Presumably this naturally shaped stone was collected, transported and used
as a tomb stone. The stone has been crudely inscribed "Edwrd Ward and his wife
Martha". The words have been made to fit the stone. A search of the Dedham Burial
Parish Register has revealed the follwoing entry "Martha of Edward Ward 23rd
September 1690". So after nearly 60,000,000 years this fascinating stone has reached its
final resting place - or has it? Much has been written about sarsen stones in recent years
including several articles by Summerfield (1979; 1980a & 1980b).
Essex Field Club Newsletter No. 22, August 1997