By Robert John Langdon
If you study any British Geological Society (BGS) geological map of Britain you will notice it shows a series of bedrock, sedimentary and superficial deposits. At a scale of 1:50,000 km and below these deposits start to form labyrinth of material that look like canals and gigantic waterways which lay under the surface on top of the bed rock. This lays testament to how the landscape must have looked at some stage in of our natural history and this is particularly prevalent in the Stonehenge area as well as other chalk bedrock outcrops.
If you study any British Geological Society (BGS) geological map of Britain you will notice it shows a series of bedrock, sedimentary and superficial deposits. At a scale of 1:50,000 km and below these deposits start to form labyrinth of material that look like canals and gigantic waterways which lay under the surface on top of the bed rock. This lays testament to how the landscape must have looked at some stage in of our natural history and this is particularly prevalent in the Stonehenge area as well as other chalk bedrock outcrops.
Stonehenge - BGS Geological Map showing superficial deposits |
These superficial deposits that resemble ancient
rivers can clearly be seen on the surface and are known to the archaeologists, geologists and the general public as ‘Dry River Valleys’ - because the river valleys are
currently dry.
But this was not always the case!
Until recently geologists believed that the contours of these chalk hills and valleys were cut during a ‘Periglacial Phases’ of the ‘Quaternary Period’, which is the current geological period that started about 2.6 million years ago - although there is no real evidence of their exact date of their formation.
But this was not always the case!
Until recently geologists believed that the contours of these chalk hills and valleys were cut during a ‘Periglacial Phases’ of the ‘Quaternary Period’, which is the current geological period that started about 2.6 million years ago - although there is no real evidence of their exact date of their formation.
Recent theories (and in Geology these
new ideas are occurring on a regular basis) suggest that these dry river
valleys are the result of water flooding, washing away the top soils and rounding
the chalk sub-soil, during the melting period after an Ice Age.
The problem for archaeologists and geologists is - which one? - For there has been several during the quaternary period.
The problem for archaeologists and geologists is - which one? - For there has been several during the quaternary period.
![]() |
Devils Dyke - a 'dry river valley' on the South Downs |
Geologists seem content to give rough estimations on the
construction date of geological objects such as dry river valleys, which for
the archaeologist can become misleading. For
although the origin of these objects is of interest, the actual dates when they could have been used my man is
even more important, if we are to understand the anthropological implications and through
this process, any archaeological findings in relation to their location.
So we must best try to understand not WHEN
the dry river valleys were formed, but when LAST did they have water running within
them?
Geological maps clearly indicate that
great rivers once flowed through Britain and we know that the greatest deluge of
water that has ever affected the landscape is at the end of an ice age, when the gigantic ice caps finally melt. In the end of the last ice age some
17,000 years ago, geologist have estimated that the ice was over two miles thick
in some places. This substantial level of ice MUST have created huge flooding all over the Mesolithic landscape including the Valleys of the South Downs, even thought they were over 100 miles away from the main ice sheet.
South Downs -BGS Geology map showing SALTDEAN |
Modern geologists now accept that the dry
river valleys are the product of water (not ice as previously believed) and looking at some extreme
examples of the soil eroded and valleys cut, we are not talking about just frozen tundra slowly melting
in the summer season - but millions of gallons of fast flowing water cutting away at the
top-soil and sedimentary deposits, all the way down to the bedrock in some
instances.
If the top soil erodes as quickly as some 'experts' also suggest - why is there 18 inches of top soil on top of the chalk today, there should be none?
![]() |
Bottom of the prehistoric riverbed - showing how close to the top soil is the sand |
Are we expecting some massive climatic event to wipe away the top soil in the near future or is the dating of the prehistoric river beds and consequently dry river valleys totally incorrect?
As a matter of practice, archaeologist
investigating Stonehenge have always ignored the obvious dry river valleys that
surround the site, as they are incorrectly perceived that this area looked as
it does today at the time of Stonehenge's construction and therefore, the River Valleys were dry in the Mesolithic/Neolithic Periods.
Our case studies (in my book - The Stonehenge Enigma) of the South Down's, the River Ouse gave us radiocarbon dates of 6290 BC +/- 180 for this same sediment. Combine this with our other case study of the Thames (shown on an earlier blog) showing it was cut in the early Mesolithic and at that time, ten times larger than it is today - we have proven beyond reasonable doubt these rivers actually existed from the start of the Mesolithic, just after the ice age great melt late into our prehistory in the Neolithic period and in some instances the medieval period as in the river Ouse.
RJL
(by Robert John Langdon)