Sarsen stones are sandstone blocks found in quantity in the
United Kingdom on
Salisbury Plain, the
Marlborough Downs, in
Kent, and in smaller quantities in
Berkshire,
Essex,
Oxfordshire,
Dorset and
Hampshire. They are the post-glacial remains of a cap of
Cenozoic silcrete that once covered much of southern
England – a dense, hard rock created from
sand bound by a
silica cement, making it a kind of silicified sandstone. This is thought to have formed during
Neogene to
Quaternary weathering by the silicification of Upper
Paleocene Lambeth Group sediments, resulting from acid leaching. The word "sarsen" (pronunciation ['sa:sǝn]) is a shortening of "Saracen stone" which arose in the
Wiltshire dialect. "
Saracen" was a common name for
Muslims, and came by extension to be used for anything regarded as non-Christian, whether Muslim, pagan Celtic, or other.