
Left: A father and son split
Jurassic nodules in search of fossils. Right: A family on a
private fossil tour at
Beachy Head
posing with a chalk ammonite.
Fossil hunting is a fascinating pastime enjoyed by families and individuals of
all ages and levels of experience throughout the year. With just a little
time spent learning the basics anyone can enjoy the thrill of finding evidence of prehistoric creatures
and the environments they lived
in. The following page offers some initial guidance to getting started,
including the best places to look and techniques for fossil hunting
effectively and safely.
What is a fossil?


Left: A fragment of
fossilised fern from a private quarry in Surrey. Right:
A large ammonite found at
Quantoxhead in
Somerset.
The modern use of the word 'fossil' refers to the physical evidence of
prehistoric life that is preserved from a period of time prior to recorded
human history. There is no universally agreed age at which the
evidence can be termed fossilised, however it's broadly understood to
encompass anything more than a few thousand years. Such a definition
includes
our prehistoric human ancestry and the ice age fauna as well as more
ancient fossil groups such as the dinosaurs, ammonites and
trilobites.
Fossils occur commonly around the world although just a small proportion
of former life made it into the fossil record, perhaps less than a billionth.
Most living
organisms simply decayed without trace after death. Thus, the abundance of fossils
reflects the immense number of organisms that have lived and the vast
length of time over which the rocks have accumulated. To read more about
how fossils form
click here.
The earliest fossils discovered date from 3.5 billion years
ago, however it wasn't until approximately 600 million years ago that
complex multicellular life began to enter the fossil record, and for the purposes of fossil hunting the
majority of effort is directed towards fossils of this age and more recent.
The geologic timescale is divided into eras which are further divided into
periods, of which the most frequently quoted is the Jurassic period
(from the Mesozoic era) - famous for
the abundance of dinosaurs at this time. To view the geologic timescale
click here.
Where to look for fossils?


Left: Fossil hunting on the
beach at Hastings in
East Sussex. Right: Fossil hunting in a quarry within the
Cotswolds.
The first step towards understanding where to look for fossils
is to appreciate the distribution of fossil bearing rocks and the
conditions that led to their formation and subsequent exposure.
The rocks reveal the conditions present at the time of their formation
and the forces that subsequently influenced their character.
There are three primary rock types: sedimentary, formed from accumulated sediment i.e. sand, silt and skeletal
remains; igneous, formed from molten rock that has cooled and
hardened; and metamorphic, sedimentary
or igneous rocks that have been altered significantly by
heat and/or pressure.
Fossils are most commonly found within sedimentary rocks due to the
favourable conditions of burial and limited alteration through time.
Sedimentary rocks form on the Earth's surface as sediment accumulates in rivers, lakes
and on the seafloor in particular. Among the common sedimentary rocks
include: sandstone, composed predominantly of grains of eroded rock;
limestone, composed predominantly of shell debris and planktonic skeletons;
and shale, formed from hardened clay (originally deposited as mud).
Sedimentary rocks may undergo considerable change millions
of years after deposition resulting in a new rock type e.g. slate. These
'altered' rocks are collectively known as metamorphic. Slate was originally
laid down as a muddy sediment which was then compacted and hardened to form
shale (a sedimentary rock), over time the shale was exposed to greater
pressure and heat within the ground, a result of continental movement and/or
tectonic activity. Over time the fabric of the
shale was altered, replacing the original fabric and converting it to a
metamorphic rock, consequently fossils within the slate are often flattened and distorted.
On very rare occasions fossils can also be found within igneous rocks where
molten rock escapes to the Earth's surface and envelops organisms in its
path, such as a tree. In this example if the molten rock cools and hardens
in less time than it takes to turn the tree to ash,
then the hardened rock may form a solid mould around the tree. Over
a short period of time the tree tissues decay leaving an empty
chamber inside the rock, some examples even preserve the texture of
the outer bark on the walls of the mould.
Having recognised unaltered sedimentary deposits as the main source for
fossils, the next step is to understand where such rocks are
located. Geology maps are a useful place to start as they reveal the
age and type of rocks present at the surface; note that the surface rock is
generally underlain by older rocks unless significant geological forces have caused
buckling/folding of the landscape.


Left: A geological
summary of northwest Europe indicating the age of the rocks.
Right: A more detailed geology map indicating
various sedimentary rocks.
BGS.
The map above-left indicates the age of the surface rocks, colour coded
according to the period in which they originally formed , for example the
Jurassic (blue) 200 - 145 million years ago (mya) and Cretaceous (green) 145
- 65 mya. A map such as this is a useful starting point to understand the
distribution of rocks and the type of fossils that might (or might not) be
encountered. For example regardless of the conditions in which the rocks
were formed, Pre-Cambrian rocks (red) which date from over 542 - 488 years
ago, won't contain reptile bones as this group did not evolve until much
later. Likewise the ammonites are confined to the Jurassic and Cretaceous
periods, at the end of which they became extinct. A knowledge of which
organisms existed during which periods is useful. To view a larger version
of the European geology map
click here.
Having established the relevance of age to the
prospect of finding certain fossil groups, the next step is to
appreciate that age alone does not dictate which fossils may be
encountered. It's useful to consider the variety of conditions
simultaneously present today and apply these principles to the
prehistoric world which had rivers, coastlines, seas, oceans and
deserts just like today. Thus sediments of different types are laid
down simultaneously and will ultimately contain different fossils
groups (e.g. Jurassic limestones may contain ammonites, but Jurassic
river sediments will not, as ammonites were exclusively marine).
Similarly changes
to the environment in a given area may
dramatically alter the type of sediments deposited at a particular
location. A vegetated region may produce coals, but a rise in sea
level may flood the area leading to the deposition of sandstones).
An example of this can be seen in the Early Cretaceous rocks of southeast of England
which contain sandstones (formed near land in a delta-like environment)
but are overlain by Late Cretaceous chalk (formed far from
land at the bottom of the sea). The transition from sandstone to chalk represents a rise in
sea levels (marine transgression) that took place globally towards
the end of the Cretaceous period, submerging much of the land and
reducing the supply of land sourced sediments; only the skeletons of
plankton continued to accumulate to any great extent (forming
chalk). Subsequently, the fossils in the sandstone are more likely
to contain dinosaur bones whereas the chalk contains fossils of
marine origin such as the ammonites and sharks.
Once the basic geology of the area is understood the next step is
to research locations where the bedrock is exposed, this isn't always easy,
as inland outcrops are often obscured beneath soil and coastal
locations may be inaccessible. Fortunately there are well documented
locations where fossil collecting can take place, these include quarries and
many coastal locations. Permission and
insurance is usually required to access quarries, as such it's best to
accompany a local geology group who have existing relationships with the
quarry operators and public liability insurance as well. Coastal locations on
the other hand are usually accessible without permission unless stated
otherwise.
Where possible the locations featured on Discovering Fossils include as
much geological information as is publicly available. To find a fossil
location within the UK
click here.
Detailed geology maps and books are available on a regional and local level
(as shown above-right) from
the
British Geological Survey and
UKGE.
What tools and equipment will you need?


Left: Roy and Louis hammer
a boulder in search of fossils at Seatown.
Right: A hard-hat and high visibility
jacket are a legal requirement in working quarries.
Fossil hunting can vary from a tranquil stroll on a beach in shorts and
t-shirt during the summer, to extreme physical challenges in the depths of
winter. As well as recognising the need to dress appropriately, it's worth
spending some time selecting the tools needed to assist you during the trip.
Preparation in advance will help ensure your visit is productive and safe.
For locations where the rock is hard, a hammer and chisel combination are
the most suitable tools; some people prefer to use a geologist's hammer in
isolation however this offers less control when extracting fossils. The
hammer should be as heavy as can be easily managed without causing
strain to the user, for individuals with less physical strength and
children a head weight of
500g or less is recommended. A chisel is required in conjunction with a
hammer for removing fossils from the rock - a
large chisel for completing the bulk of the work and a smaller,
precise one for finer work.
A chisel composed of cold steel is recommended as these are
especially engineered for hard rock.
While
hammering rocks there's a risk of injury from rock splinters
unless the necessary eye protection is worn. Safety glasses ensure any splinters are deflected
away from the eyes. Eye
protection should also be worn by spectators as splinters can
travel several metres from their origin.
For more information and examples of the tools and equipment
recommended for fossil hunting
click here.
When is the best time to fossil hunt?


Left: Fossil hunting after
stormy weather can provide the best opportunity for finding fossils.
Right: In summer the pace is a little more
leisurely.
Fossil hunting can be undertaken throughout the year, although the
winter and spring tend to yield a greater volume of finds along
coastal stretches due to the scouring action of the wind, rain and
rough seas. During the summer, when the rate of erosion is generally
lower, fossil collecting is more reliant on splitting prospective
rocks or examining air-weathered surfaces.
Regardless of the time of year, in coastal locations it's best to
coincide your visit with a falling tide. If the tide has already begun to rise
upon your arrival then collecting will be confined to a
limited area and time. Most coastal locations follow a 12 hour
cycle, with low-tide occurring 6 hours after high-tide and then
rising to high-tide 6 hours later. Local tide times (up to seven
days in advance) are available on the BBC's website
click here.
How to fossil hunt safely?


Left: A hard-hat is
recommended in areas where falling rocks may occur. Right:
Make a note of the tide times before you leave and avoid getting cut
off.
For the majority of time, when
undertaken sensibly and with knowledge of the personal risks, fossil
hunting is reasonably safe; however it's not possible to eliminate all risk, as is the case with many other recreational activities too.
Productive fossil collecting locations typically occur in areas
with high rates of erosion, mostly due to natural forces and sometimes by the actions of people. In these areas you're likely to encounter
unpredictable terrain including:
falling rocks, slippery surfaces, areas prone to isolation by the
incoming tide, steep drops and unstable surfaces. In extreme cases
these hazards could result in serious injury.
For more information about the hazards of fossil hunting and
the precautions to take
click here.
Considerations before extracting a fossil


Left: A brush is
used at Blue
Anchor to sweep away the surface sediment in order to assess the
ammonite's condition. Right: A bivalve in
situ at Alum
Bay.
In most instances fossils can be collected without causing
unnecessary damage to the area or breaking the law, however there
are locations and instances where visitors must follow
specific guidelines when collecting, especially
SSSIs. An
example of this would be the giant ammonites on the foreshore at
Peacehaven which fall within the SSSI protection status. It's
worth researching the area beforehand to understand the
restrictions, where possible this information is outlined within
each of the locations featured on Discovering Fossils.
As a general rule fossils that are in situ (in their
original position within the bedrock, beach platform or cliff-face) should not be collected.
Extracting a specimen that is in situ can cause
damage to the surrounding area, it's also a much more complicated
procedure and can result in irreparable damage if
undertaken carelessly. There are possible exceptions to this rule, for
example if the specimen is of scientific value and
at risk of being damaged. In instances such as this, an experienced
member of the scientific community should be consulted to
offer support and advice; it's best to avoid commercial collectors
in these circumstances. Experienced, independent advice can be
sought from any of the Discovering Fossils team, we also have
contacts around the country who can help you.
Extracting fossils


Left: A fragile
echinoid has been pedestalled to help protect it during extraction
using a hammer and chisel. Right: A steel probe is
useful for fragile specimens.
Once a decision to extract a fossil has been reached the next step
is to carefully plan an appropriate method of extraction. During the
extraction the fossil is at its most vulnerable; the surrounding
rock (matrix) can be unpredictable and crack or shatter when least
expected. A well planned extraction reduces the risk of damage and
takes into consideration the desired end result i.e. how the
specimen will be prepared and displayed. It's worth pausing for a
moment and considering the various outcomes that may arise.
In some cases it may be necessary to strengthen the specimen and/or
surrounding matrix before progressing. For example it's common to
find naturally occurring cracks passing nearby, beneath or even
through the fossil; a weak matrix might crumble during the
extraction and must therefore be stabilised before progressing. A
fast-setting superglue is a controversial technique but useful in
these situations, providing essential stability before hammering. Note that
overuse or misguided application can create irreversible damage to
the specimen (children should be supervised at all times). As a
general rule use as little glue as necessary and apply it as far
from the specimen as possible - a drip of liquid superglue will
follow the crack unaided. Avoid allowing the glue to make
contact with the surface of the fossil as it can be difficult to
remove. Once the fossil and matrix are stable the extraction can
take place.
It's advisable to retain as much matrix around the specimen as
possible as this will protect it during extraction and
transportation. The example above-left shows a fragile echinoid
shell exposed on an air-weathered chalk surface. Before reaching the
stage shown a pedestal was created around the fossil, this was
achieved using a hammer and sharp chisel to remove the matrix to within 3cm of
the specimen and to a similar depth. The base of the pedestal provides
a safe horizon below the specimen to undercut it, a few
gentle taps releases the pedestal with the fossil undamaged on top.
For fossils contained within softer rocks and clays a steel point
can be used instead of a hammer and chisel. The example above-right
shows a fragile gastropod shell being carefully extracted from
in situ. In this instance the matrix isn't desired and the
shell can be removed safely and transferred to a padded container.
Transporting fossils safely


Left: Foam wrap is
the best all round material for protecting larger specimens in
transit. Right: A padded compartment box is useful
for smaller specimens.
Once the specimen has been extracted it needs to be carefully
wraped with foam or an equivalent such as newspaper, being
careful not to crush it in the process. Before beginning observe
whether the specimen is dry or wet, the aim is to maintain the
fossil in its current state until it can be prepared at home. Rapid
changes in water content resulting from drying or soaking can cause
damage to the specimen. This is especially important for fossils
found on the coast which require soaking to remove unwanted salt
from the matrix and fossil; a fossil which has been allowed to dry
in transit may be damaged when it comes to soaking.
Place the fossil in the centre of a single sheet of foam and
fold each of the corners over and specimen. Continue wrapping until
the specimen is contained within a small parcel, apply as much foam
as you feel necessary to prevent any damage occurring from knocks or
bumps. To finish off use a couple of elastic bands to hold the foam
in place. Selotape can also be used but is unsuitable in wet
conditions.
An alternative method of protecting smaller
specimens is to use a small compartment box partly filled with
cotton wool to prevent the fossils from moving around (as pictured
above-right). Cotton
offers significant protective benefits over the potential
drawbacks. It should be noted that cotton wool can
(in come cases) damage fragile specimens by snagging the surface. Extra care
should be taken when removing the cotton wool from around the
specimen.
Recording key information


Left: Simply
positioning a finger in the photograph is an effective way of
recording the position at which the fossil was found or originated
from.
Right: At
Bracklesham Bay
the buildings on the skyline are used as a landmark for future
reference. Permanent landmarks are preferred if possible.
It's good practice to document the locations at which fossils are
discovered as this contributes to their scientific value. Keeping a record of the location and horizon (if known)
makes the task of identifying fossils at a later stage less
complicated; likewise if the specimen transpires to be a new
species, these details will prove essential. An accurate record of
the fossil will also be valuable to future recipients such as
museums and other collectors.
A digital camera is an effective tool for recording this
information. It's worth taking multiple photos from different
angles, capturing as much of the backdrop as possible and indicating
using a finger the position at which the fossil was found. In
addition to taking photographs, any specific information that can't
be captured visually e.g. the formation or bed name (if known)
should be noted on a paper pad.
Once at home, the information gathered should be stored in a safe
place and a corresponding label affixed to the underside
of the specimen for easy reference.
Basic fossil preparation


Left: Fossils
recovered from coastal locations may require soaking to remove the salt.
Right: A microscope is useful for conducting
delicate preparation work.
Having successfully retrieved the fossil the task of preparing it
for study and display can begin. The process can be lengthy and
complicated, but with practice the results can be truly outstanding,
likewise some fossils require little preparation beyond basic
stabilisation.
As a large number of fossil collecting locations occur on the coast, salt contamination
is the first threat that needs to be addressed. Salt naturally
attracts water from the air, dissolving in the process and
re-crystallising as the humidity reduces; conditions in a typical
home or museum fluctuate frequently, accelerating the process. Left
untreated salt crystals can cause long-term instability to the
matrix and fossil. To remove the salt the specimen must be soaked in
fresh water. Some materials however should not be soaked, as doing
so can cause the matrix to disintegrate e.g. Gault Clay. Others,
such as flint,
are simply too dense to be affected by salt. If in doubt experiment on a small, unwanted piece of the
matrix.
If the fossil
has been in transit or storage long enough to dry out, or was collected on a
dry day, you'll need to cover it with a wet kitchen towel or cloth,
this will allow the water to be absorbed gradually. Try to avoid
submerging dry specimens in water as rapid exposure is likely to
shatter soft matrix and the fossil with it. You may need to leave the
fossil covered for up to 48 hours, adding small amounts of water to
the towel as required; a sealed container with a small amount of
water in the bottom can assist the process. Once the moisture
levels have been increased, carefully submerge the fossil in fresh
water and soak it for 1-2 weeks (the longer the better), changing
the water every few days to assist the process. It's a good
idea to keep the container out of direct sunlight to prevent algae
growth.


Left: The moisture
levels in this bivalve from
Bracklesham Bay are increased
gradually by wrapping it in a damp cloth and placing it in a few
millimetres of water.
Right: After 24 hours the fossil is saturated and
can be safely submerged in water. The specimen suffered no damage as
it was gradual moistened prior to soaking.
Once the soaking is complete and the salt extracted the fossil can
be removed and any remaining dirt or unwanted loose matrix brushed
away,
a soft bristled toothbrush is an effective tool in most instances.
The specimen should be allowed to dry naturally away from any
direct heat source. Small specimens may dry
in a matter of days whereas larger examples may require a week or
two. Keep a close eye on the specimen throughout the drying phase
and consolidate (with a liquid superglue) any major cracks which may
develop as the matrix contracts.
With the specimen now clean and dry the next step should be to
address any remaining cracks that may interfere with the further preparation. A
few drips of fast setting liquid superglue is one possible solution
(see below-left). For hairline cracks and to strengthen and protect surface
details a dilute solution of Paraloid B72 in acetone can be applied,
this also has the advantage of being removable at a later stage
(unlike superglue which is permanent).


Left: A thin liquid
superglue is applied to consolidate the weak outer section of
this mammoth tooth, being careful to avoid spilling onto the tooth's
surface.
Right: Paraloid B72 dissolved in acetone is used to
strengthen the fragile surface of the tooth; the excess can be
easily removed with acetone at a later stage.
Having stabilised the matrix and reduced the risk of cracks
affecting the preparation area the delicate task of exposing the
fossil can begin. The aim is to remove enough of the surrounding
matrix in order to display the fossil as fully as possible without
compromising its long-term stability. Moderation and control are
required as over ambitious preparation can leave the fossil
vulnerable to damage or cause it to fall apart.
Depending on the particular specimen there are various preparation
tools and techniques available. For specimens surrounded by
relatively soft matrix such as chalk, much of the work can be
undertaken with a simple metal tool - a dental probe can be easily
adapted to form an effective spear-shape digging tool (see example
below-left). A microscope is useful for undertaking precision work,
especially if the specimen is fragile.


Left: A spear-shaped
dental tool is used to remove chalk matrix from around a fish skull.
Right: An air-abrasive removes chalk from the
surface of an echinoid.
For removing especially hard or large volumes of matrix a mechanical
tool such as an air-abrasive (shown above-right) or an air-pen are
effective choices. An air-abrasive dispenses a stream of abrasive
particles under pressure which rapidly erode the matrix, albeit in a
controlled way. Similarly an air-pen delivers effective results
using a vibrating tungsten point to remove the matrix.
Reporting an important find


Left: One of many
dinosaur footprints belonging to trackways discovered in a quarry
near Oxford in 1997. Reported to various international
organisations.
Right: A well preserved cupedid beetle showing body
and both elytra. Reported to Kent RIGS - see
Wealden
News.
Occasionally remarkable fossils are discovered, more often than not
by an amateur fossil hunter. It's important that fossils of
scientific value are reported to the relevant organisations in order
that they can be considered for study, identification and safe
extraction. If you
think you've found something of scientific value please contact your
local museum or a member of the Discovering Fossils team who will
put you in contact with the relevant people.
Donating fossils to a museum


Left: A triceratops
skull at the Hunterian Museum in Glasgow. Right: A
drawer of 'type fossils' from the Chalk at the Booth Museum in
Brighton.
There are instances where an individual fossil or private
collection would benefit public understanding of the subject by
residing in a publicly accessible location, such as a museum. It's
not uncommon for private collectors to amass hundreds, even
thousands of specimens, and while there are arguably benefits to
this in the short-term, it's important that the scientific and long-term
future of the specimen(s) are also considered.
For individual fossils that are known or suspected to be scientifically
important, such as a new species or one that exhibits a unique or
rare characteristic, it's good practice to allow
academics access to study and document it. This may also require that the
specimen is made permanently available to other academics, in which
case a donation to a relevant museum should be considered. Donations
are sometimes provided in return for a plaster/resin replica if
requested.
A museum also makes a good permanent home for private collections
after the owner has passed away. Although it's a thought none of us
likes to consider, it's responsible to make plans for the
collection's future. The absence of a future plan could mean the
collection falls into the wrong hands and is ultimately split up and
sold to commercial dealers. The ideal museum is one that is major
enough that the collection will be known to relevant scientists and
ideally has a local/regional connection with where the specimens
were found. If possible the museum's curator and close friends and
family should be notified of these plans in advance.
For further advice or to discuss the donation of an individual
specimen or collection please
contact us.
Recommended reading


Left: The Natural
History Museum's British Fossils series. Right:
Peter Toghill's introduction to The Geology of Britain.
Below are a selection of recommended books for the study of
palaeontology in Britain and internationally as well. Some of the
examples listed are no longer in print and will need to be sought
from a second-hand supplier - a quick online search usually provides
several possible sources.
The Geology of Britain - an introduction, Peter
Toghill, ISBN: 1840374047
British Palaeozoic Fossils, The Natural History
Museum, ISBN: 1898298718
British Mesozoic Fossils, The Natural History
Museum, ISBN: 1898298734
British Caenozoic Fossils, The Natural History
Museum, ISBN: 1898298777
British Regional Geology (Series), British Geological Survey,
ISBN: 0118844822 (Bristol and Gloucester example)
A Dynamic Stratigraphy of the British Isles, R. Anderton, P. Bridges, M. Leeder and B. Sellwood,
ISBN: 0412445107
Vertebrate Palaeontology, M. Benton, ISBN:
9780632056378
Fossil Invertebrates, R. Boardman, A. Cheetham, A.
Rowell, ISBN: 0865423024
Other recommendations available on request.

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