The Friends of the Speeton Clay
If you go to Speeton (the southern end of Filey Bay, North Yorkshire, U.K.) you may see some strange sights. You may see chalk pebbles with writing on them, stuck into the mucky grey cliffs. And occasionally you may see the creature responsible for these artefacts. It is one of a strange species of geologists known as 'The Friends of the Speeton Clay'. They are a bit like normal geologists (if that is not a contradiction in terms) but they have a habit of muttering strange numbers to themselves, or (if they get the chance) other people ! They also write these numbers on pebbles of chalk and stick them into the cliff. They also tend to abandon the familiar geological hammer in favour of ice picks, mattocks, axes, trowels or custom made tools.
If you like you can join in their
conversations: if they say "LB2B" or "C7G" you can say 'ooh yes' and nod enthusiastically.
But do not get carried away and reply "E5C", because they would not have heard
of this one before !
The whole thing started when a chap called G W Lamplugh started collecting fossils over a hundred years ago. He was an amateur at the time and lived at Bridlington. He would camp on the top of the cliff and dash down at low tide to collect fossils. He went on to become a famous professional geologist and Fellow of the Royal Society and member of the Hull Geological Society.
So what did he discover
? What is the addiction suffered by 'the Friends of the Speeton Clay' ? These
clays are the only U K exposure of the marine lower Cretaceous. Lamplugh did
some very early stratigraphic logging and divided them into 6 units using the
belemnites
as zonal fossils. He labelled them A to F from the top. These days we would
have started from the base. The F beds were not really part of the Speeton Clay,
and are Late Jurassic (Kimmeridgian stage) in age. The E Bed or Coprolite Bed
is thin and very hard, and used to be mined for phosphates (sometimes you can
see old pit props in the mud). The nodules in the B Beds used to be mined for
making cement.
If you get hold of a good,
accurate log of the Speeton Clay, the first thing you will notice is that it
will still be a bit vague about parts of the A & B beds, because they are
rarely exposed. Also, be aware that 'Friends of the Speeton Clay' have a vivid
imagination. Strata are described as being bright blue, yellow, green, etc.
leading the unwary visitor to expect a northern version of Alum Bay ! The truth
is that all the clays, particularly when dry, are basically GREY. And do not
expect to always find the bed you want - the cliffs are moving and eroding;
sometimes the beach pebbles are banked up high at the base of the cliff; and
beach exposures at low tide are rare and ephemeral. Be warned, mudslides have
been common in recent years - if you don't see any footprints in the mud don't
try to walk on it !!!
So part of the fascination
is the impermanence of the exposure - you never know what to expect ! The other
fascination is the strange fossils. For some reason, Speeton has fossils which
you would not expect.
The Belemnites themselves
are a bit unusual, big chunky Acroteuthis and the delicate Hibolites that all
seem to be corroded at their front end (remember the pointy end of the belemnite
fossil is at the tail end of the belemnite animal). Then there are the famous
Speeton
'shrimps'. These little
crustaceans are really very common in some beds and some have original colour
banding preserved. Larger crustaceans have been found as well. The ammonites
are lovely: beautiful tiny
ones preserved in pyrite
and large ones that are un-coiled
! There are also sea urchins,
brachiopods including Lingula, a variety of bivalves and worms of the encrusting
and solo coiled varieties !
Be warned, it is an addictive
place. But to get to know it properly, it is well worth getting to know some
'Friends of the Speeton Clay' and asking them to show you round a couple of
times. Then the wonders that will start to reveal themselves to you can be fitted
into the stratigraphy and a whole new world opens up.
Pictures of Speeton
Geology of the Speeton Clay
The Fossils of the Speeton Clay
Join the Friends
Links to related sites