A palaeolithic assessment at the new school site, Stone Lodge, Dartford, carried out in 2019, confirmed the presence of Boyn Hill / Orsett Heath gravels. These have often been associated with the discovery of important palaeolithic remains.

From the report: "surface varies between 34.50 and 36.16m OD. These exhibit marked vertical and lateral
variation in dominant particle size, from clast-supported gravel to matrix-supported sandy clay
with sand laminae in TP3 at 33.45m OD. This variation is the result of changes in the flow
regime within former river channels, larger clasts being indicative of bedload transport in more
energetic flow. The deposits are assigned to the Boyn Hill/Orsett Heath river terrace. This is
the oldest terrace of the modern route of the River Thames, subsequent to its diversion during
the Anglian glaciation (Marine Isotope Stage (MIS) 12; c. 478-420 thousand years ago). Initial
aggradation of river terrace deposits takes place during the warming phase of a cold stage,
when sand and gravel are laid down on a new river bed, however the majority of the gravel is
laid down during a cooling phase entering a cold stage when the gravel bedload of a river
increases due to the loss of vegetation meaning more sediment is available for erosion and
subsequent transport. The Boyn Hill/ Orsett Heath terraces are thus dated to the end of the
Anglian glaciation (MIS12) and the onset of MIS 10 following the Hoxnian interglacial (MIS
11)."

<1> AB Heritage, 2019, New School Site, Stone Lodge, Dartford, Palaeolithic Assessment Report (Unpublished document). SKE53554.