This annual event is for the whole family where you can enjoy:
hands-on science for all ages
Entrance to the Grand Marquee is FREE (though donations are encouraged!). Some talks and events in the theatre are priced - please see website for details.
I shall be representing the NHM at the Lyme Regis Fossil Festival this weekend. It is a great event for all the family, please pop along and introduce yourself. I shall be in the Natural History Museum marquee outside the theatre. I hope to see you there!
Lyme Regis has played a vital party in our understanding of fossils. The famous Mary Anning lived is from Lyme Regis, she was self-educated, working class and a wonderful role model to demonstrate how we can all contribute to science. In 1810-1811, her brother found the 1st complete Ichthyosaur. Her discoveries were some of the most significant geological finds of all time.
Ichthyosaurus communis (Conybeare) collected by Mary Anning from the Lower Lias, Lyme Regis, Dorset.
(on display in the Reptile Gallery at The Natural History Museum, London).
Asteroceras from the Lower Jurassic of Dorset, England.
The 2015 Festival of Geology will take place at University College London
Introduce yourself to Fiona Fearnhead, Christina Fisher and Claire Mellish, representing the NHM
Hope to see you there!
Saturday 7th November 2015 at University College London
Sunday 8th November - Festival field meetings
"Exhibitors from the World of Geology, Fossil and mineral displays, stonecraft, books, maps, geological equipment, jewellery, beads, Building Stones walk around UCL with Ruth Siddall, Tours of the UCL Earth Science Laboratories, Poetry and Geology and more..."
Hi Fossil lovers! Tips to help you identify your fossils:
Fossil Guide iBook - a useful resource for the basics about fossils and how to identify many of the common ones.
All the major groups of fossils are illustrated with clear diagrams and beautiful, pin-sharp photographs of real specimens.
Suitable for beginners as well as those with some knowledge, this authoritative and helpful multi-touch book has been produced by the Open University, in collaboration with the Sedgwick Museum, Cambridge.
It covers invertebrates, vertebrates and plants, and each fossil group is illustrated with a gallery of photos.
Some specimens are presented as 360-degree rotational objects to provide a tactile feel, and the detailed structure of other fossils is captured with high-resolution views of thin sections under a microscope.
The Introduction includes useful advice and tips on responsible fossil collecting. As well as being suitable for the educated amateur, this book will also be useful for teachers and should provide a stimulus for children interested in fossils and the wonderful world of geology.
SPECIMEN LABELS are very important because they provide information that will help with identification and provide useful scientific data (without this information specimens have not scientific value). Please feel free to adapt the specimen labels in the document attached
1. Print specimen labels before you visit a locality, this will make collecting quicker and easier.
You can adapt the specimen labels attached and insert your name to save time and effort.What to include?
exact location: name of beach/field/garden/farm
Was it loose on the ground or dug up?
name of town
2. If you don't have a label, even a scrap of paper will do ....(I have inserted bus and train tickets which show the date and destination).
3. Keep specimen labels, a pencil and notebook handy along with plastic bags so you can wrap and label your specimens as soon as you find them.
4. Newspaper is very useful for wrapping specimens, which also prevents them drying out too quickly
THE FOSSIL COLLECTOR'S TOOLKIT:
Always follow the Geological Code
THE FOSSIL COLLECTOR'S TOOLKIT:
notebook, pencil and marker pen
newspaper for wrapping specimens, which also prevents them drying out too quickly
appropriate footwear and clothing
long-handed trowel, fork, long shoe-horn for overturning small nodules
First Aid kit
water and a snack!
A hammer is useful, but do remember to wear goggles when splitting rocks.
Brushes and a sieve can be useful to avoid carrying unnecessary sand or clay
Consider all aspects of heath and safety regarding the site and also from your perpective and the people with you. A useful place for fossil localities, the sorts of fossils that you might find, specific safety considerations and may be found here. You THere is oftehttp://www.discoveringfossils.co.uk/locations.htm
IMPORTANT - Check the times of tides before the visit
The essentials of the Scottish Fossil Code:
Seek permission – You are acting within the law if you obtain permission to extract, collect and retain fossils.
Access responsibly – Consult the Scottish Outdoor Access Code prior to accessing land.
Be aware that there are restrictions on access and collecting at some locations protected by statute.
Collect responsibly – Exercise restraint in the amount collected and the equipment used.
Be careful not to damage fossils and the fossil resource.
Record details of both the location and the rocks from which fossils are collected.
Seek advice – If you find an exceptional or unusual fossil do not try to extract it;
but seek advice from an expert.
Also seek help to identify fossils or dispose of an old collection.
Label and look after – Collected specimens should be labelled and taken good care of.
Donate – If you are considering donating a fossil or collection choose an Accredited museum,
I thoroughly enjoyed a crinoid Geoblitz (systematic review of crinoids using Geoblitz criteria below) with the curator Neil Owen of Leeds Museum. There were some interesting specimens - I particularly enjoyed seeing the large slab of Woodacrinus crinoids - there were juveniles as well adult crinoids.
Stars were given GOLD= High (meets all four of he criteria), Silver and Bronze .
Scientific – is of taxonomic or other research importance; including being cited or published.
Historic – associated with a known collector, donor, locality, site, discovery, date or institution; support research in a specific field
Rarity/Uniqueness – internationally, nationally or regionally important; rare in museums collections and/or from an important local or SSSI site
Public Engagement – has an interesting history, has good public engagement potential for display, events or publicity.
BACKGROUND - Leeds Museum Geology Collection (over 24, 000 Minerals, Rock Types and Fossils from around the world)
The Geology Collection dates back to the 1820’s and has been awarded a “Designated Outstanding Collection” by the Arts Council England.
The fossil collection comprises (approx. 12,000 specimens – some were donated from well known collectors:
The Ethlered Bennett’s collection of rocks and fossils,
Ernest E. Gregory collection of rocks and fossils
Cyril P. Castell collection of fossils.
What is a Geoblitz? what is the aim?
To assess the collection and to identify individual specimens, therefore highlight specific key taxa for star grading system.
This assessment/identification will be used to enable greater usage/engagement of the collection and promote Star specimens for :
The False widow spiders (Steatoda spp.) form a group of species that, because of their general resemblance to the much more notorious Black widow spiders (Latrodectus spp.), can cause concern when found in Britain. In fact, these False widow spiders and the true Black widow spiders belong to the same family, the Theridiidae (comb-footed spiders).
Six species of False widow spiders occur in the UK (Steatoda nobilis, S. grossa, S. bipunctata, S. albomaculata, S. triangulosa and Asagena phalerata), all are black or brown, rotund species up to about the size of a small finger-nail (maximum body length of adult female 15 mm). An additional species, Steatoda paykulliana, is an occasional import in fruit shipments. Females have a globular shiny abdomen, while males have a smaller one with clearer markings. All species have a narrow white or lighter band around the front of the abdomen. A trait that gives the name to the family is the presence of a particularly well-developed comb of serrated bristles on female’s fourth tarsus, visible with a lens on the largest species. The webs are a tangle of criss-cross threads which may become quite dense in the centre if left undisturbed. Here are some details for the species most likely to be seen in Britain:
Noble false widow spiderSteatoda nobilis ♀ 8.5–14 mm; ♂ 7–10 mm. Always larger than S. bipunctata and usually larger than S. grossa. Abdomen pattern often described as “skull-shaped” but more like a pentagon, clearer in males and dimmer or sometimes absent in females. Legs uniformly red to brown.
Cupboard spider Steatoda grossa ♀ 6.5–10 mm; ♂ 4–6 mm. Females usually darker than S. nobilis and S. bipunctata, purplish-brown, evenly-coloured dark legs or with lighter stripes, pattern of two clear triangles and lateral bars (see photo) often dim or missing in the darkest specimens. Both sexes with lighter crescent on the front of the abdomen, but this is often absent too. Front legs longer that in S. nobilis and S. bipunctata.
Rabbit hutch spiderSteatoda bipunctata ♀ 4.5–7 mm; ♂ 4–5 mm. Distinctive appearance with median band on abdomen, clearer in male, but fainter, partial or missing in female. Dark transversal lines over the tip of the abdomen. Legs with dark stripes visible more than in any other Steatoda in Britain.
False widow spiderSteatoda paykulliana ♀ 8–13 mm; ♂ 4.5–6 mm. Black body and legs, with characteristic midline pattern on abdomen, with triangles or chevrons on median band. Both these and the band in front of the abdomen can be white, pale yellow, orange or red.
Noble false widow spiderSteatoda nobilis Well established in the southern counties and spreading north. It has been introduced with bananas from the Canary Islands and Madeira. In and around houses and other buildings. Prefers elevated positions such as the top corners of rooms and conservatories, where it hunts flying insects.
Cupboard spiderSteatoda grossa Has colonised England, Wales and Ireland; widespread in northern Europe. Usually in houses, but occasionally in sheltered spots outside and away from habitations. Prefers hidden areas near the ground under furniture, dark low corners, where it hunts for woodlice and crawling insects.
Rabbit hutch spiderSteatoda bipunctata Widespread and common in Britain and northern Europe. It lives mainly in and around sheds, pet houses and clutter in gardens, but sometimes on tree trunks. Frequent in domestic rubbish which has been dumped illegally, well away from houses.
False widow spiderSteatoda paykulliana Not so far established in Britain, but repeatedly imported with produce from the Mediterranean, especially with grapes. It hides in cracks in the ground and under stones.
False widow spiders are synanthropic species (= living almost exclusively in association with man) hanging upside down in small webs known as tangle webs. Adult females can live for a few years and survive for long periods without water. Adult males live for only a few months and are usually seen in summer and autumn. They cease to feed once mature, their sole purpose being to mate. The males have smaller and more clearly marked abdomens. They also have a stridulatory apparatus of file and scraper type (ridges on the rear of the carapace and teeth under the front end of the abdomen). They court females with sounds just about audible, produced by rapid vibrations of the abdomen. The females lay eggs in white, spherical egg-sacs produced at intervals. Their number depends on the food supply and are laid from spring through to autumn. The eggs hatch in 2-4 months. Local dispersal is achieved through ballooning on silk threads. Longer distance dispersal is aided by transportation of goods by road, rail and the shipping network.
Spider bites and first aid
If handled unwisely or accidentally, False widow spiders are capable of biting humans. False widow bite effects are similar to the Black widow’s, but milder and without diaphoresis (profuse sweating).The bite is always followed by regional pain, sometimes (25%) severe (greater than a bee sting), lasting between 1-12 h, rarely over 24 h. The pain can radiate from extremities (hand, foot) towards the body. Some bites (30%) produce nausea, headache, lethargy, and malaise. Most bites cause only minor effects and resolve with no medical intervention. False widow venom cannot cause necrotic ulcers. Allergic (hypersensitivity) reactions or infections are very unlikely. Very often skin and soft-tissue infections are wrongly reported by patients as ‘spider bites’ although a spider was not actually caught biting. Doctors must be aware, so that they can recognise the real cause and treat it effectively.
If bites happen, clean the bite with mild soap and water to prevent infections. You may apply a cold pack to relieve the pain and to slow the spread of venom, but don’t apply ice directly on skin! Mild analgesics (pain killers) may help relieving the pain. If you begin to experience any serious symptoms, you should seek immediate medical help.
Conservation and control
False widows are not native to Britain and thus not granted any conservation status. You can treat them as pests and remove them from your property if you wish to reduce the risk of getting bitten. However, most people are reluctant to kill spiders and prefer to live in harmony with them. False widows seem to have found an unoccupied niche in British habitats; we have no evidence that they upset the natural balance since their arrival. In houses, they are natural enemies of many unwanted insect guests. To prevent getting bitten, be careful when putting on gloves or boots that have been left unused for a while, as spiders may seek refuge and hide in those.
If you decide sharing your home with spiders is too risky, you can catch and release them in the garden. You can buy different spider catchers which will help you handle adult spiders without actually touching them, or improvise your own devices from cups and cards – anything that will avoid you getting bitten or the spiders getting crushed in the process.
The Bread beetle, Stegobium paniceum, also known as the Biscuit beetle (or the Drugstore beetle in the U.S.A.) is one of the commonest pest insects of stored food. It is able to feed on a variety of plant and animal products including bread and flour and even hot spices and drugs. However, this beetle is not harmful to health and despite its close resemblance to the Common furniture beetle or Woodworm beetle (in the adult stage), it does not feed on wood.
The adult beetles are usually noticed first. They are small, between 2 and 4 mm in length, reddish-brown and, under magnification, reveal fine grooves running lengthways along the wing cases. Furniture beetles (or Woodworms) are similar but are somewhat larger and darker and their antennae are shorter than the legs (in Bread beetles the lengths are similar). There are three flattened segments at the tip of antennae. The head is partially hidden by the pronotum (the plate that covers the upper part of the thorax). Biscuit beetles have large dark eyes.
Antennae with many serrations, while Biscuit beetle has three large ones at the tip. Has much weaker punctures on the surface of the wing covers (elytra). Eyes easier to see from above. Different shape of pronotum.
The Biscuit beetle occurs in houses, stores, warehouses and kitchens throughout central and northern Europe, including the UK, sometimes in very large numbers. It is known as a cosmopolitan species.
In common with other beetles, this species passes through four life‑stages: egg, larva, pupa and adult (pictured below). The speed of development through the life cycle depends on temperature, moisture, quality and abundance of food. In cool temperatures (below 15ºC) there is only one generation per year, in moderate temperatures two, while at higher temperatures (above 23ºC) there may be five or more.
Eggs are laid by mated females on or near the foodstuff. When the larva emerges from the egg, it is less than 1mm in length. In its search for food, it may bite into packaged or hidden food sources. The larva increases in size and, at about 5mm in length, it enters the pupal stage. Before emergence as an adult beetle, a minimum of nine days is spent as the pupa in an oval shaped cell moulded by the larva using the food material.
Damage and control
Because the Bread beetle larva thrives in dark, warm, undisturbed places, it is essential to search thoroughly for the food‑source of the larva if adults are found wandering around. Rarely-used dried-foods such as flour or spices are often the source of an infestation. Removing disused and old foodstuff should eliminate an infestation.
Adult beetles may be seen around fire‑places and air vents with no apparent food‑source available. These are likely to have come from nests of wasps or birds in the attic. Beware also of bread in fire‑places that has been dropped down the chimney by birds. With suitable hygiene, and by preventing access into the attic by nest‑builders, the successful eradication of this pest should be assured.
We have had an interesting specimen to identify, bought in India some 40 years ago, beautifully carved into a small Buddha head. The specimen was extremely hard and must have been carved by someone very skilled because it is only about 3 cm high.
We identified the stone as corundum, the scientific name for rubies and sapphires. Gem quality corundum is diagnosed as ‘ruby’ if it is red. All gem quality corundums which are not red are called sapphires even the pink ones like this Buddha!
In the last few days you may have been lucky enough to see a shooting star as one of the year's biggest meteor showers was displayed in the skies over Britain. But does a meteor ever become a meteorite? And how do you know if you have found one? Well in this blog I will tell you a little more about meteors and meteorites, what to do if you think you have found one, and how to find out more at Meteorites Day 2012, a special event at the Museum on 2 September.
Over the weekend from the 11 to 15 August the UK was treated to the height of a meteor shower recognised as one of the best and most reliable meteor showers in the northern hemisphere. The Perseid meteor shower happens every year between late July and mid August and at its peak can produce tens of meteors an hour.
Originating from the debris stream left by the comet Swift-Tuttle as it orbits the sun, the Perseids are so called because they often appear to come from the constellation Perseus - but as the number of meteors increases they can be seen all across the night sky.
You may think that this event would lead to an increase in meteorite discoveries that are reported to the Identification Service here at the Museum, but meteors are formed from very small particles of matter ejected from the comet, that burn up completely in the atmosphere. This means that if you see a meteor you are unlikely to find a resultant meteorite.
A meteorite discovery from Tanzania
But what if you do think you have found a meteorite - what can you do about it? Well before you jump to conclusions there are a few simple tests you can do on your possible meteorite.
STEP ONE: Test to see if your discovery is magnetic
All meteorites have some degree of magnetism; even the stony meteorites have flecks of iron and nickel mixture throughout the rock that distinguishes them from terrestrial rocks. You should be able to detect the magnetism with an ordinary fridge magnet, so if your object is not magnetic at all - then it is most likely not a meteorite.
Test your object with a fridge magnet
STEP TWO: Check the density of your discovery
Meteorites, especially iron meteorites, tend to be far more dense than some of the more commonly mistaken terrestrial rocks, so if your specimen is light in your hand when you pick it up, then again it is unlikely to be a meteorite.
Your object should be heavy for it's size
STEP THREE: Look at the surface of your discovery
Meteorites are characterised by something called a fusion crust - when the meteorite comes through the atmosphere the intense heat of entry causes the surface of the meteorite to melt. So if you can see cracks and bubbles or even other bits of rock or mineral stuck to the outside of your discovery, then once again, it is unlikely to be a meteorite.
The surface of your object should be smooth with no bubbles (right)
So what do you do if you have done these three tests and all three suggest that you have found a meteorite? Then bring it in to the Museum! On Sunday the 2nd of September the Museum are holding a 'Meteorites Amnesty' with members of our Earth Sciences department on hand and some genuine meteorites you can touch and compare against your own discoveries.
There will also be talks and activities throughout the day all about meteorites. However, if you miss this event, don't worry. Just send us a photo at the Identification Service email (firstname.lastname@example.org) or bring your specimen in on another day and we will let you know if you have a meteorite or a meteor-wrong!
Can’t make it in to visit us on a weekday?We also open the first weekend of each month from April to October, and for a few other special events.We are usually in the Museum on these weekends, but sometimes we get out and about to other wildlife events in the UK.The weekends we are in the Museum you can drop in with identification enquiries or book to use the reference collections.When we are out and about we’ll still look at your identification enquiries wherever we are, but there will be no access to the reference collections.
Please note these dates and events are subject to change, so do check with us to avoid disappointment.
The weekends we are open this year are –
Saturday 31st March and Sunday 1st April
If you are in the Museum on Sunday 1st April why not come along to the Spring Wildlife day in the Wildlife Garden?
Friday 4th – Sunday 6th May
PLEASE NOTE we will be off site this weekend at the fabulous Lyme Regis Fossil Festival, so there will be no Identification Service in the Museum
Sunday 27th May – Big Nature Day
We will be hosting a nature fair, putting members of the public in touch with amateur naturalists, societies and recording schemes from across the country. Regardless of whether you are interested in ferns, frogs, spiders or stinkhorns there will be a society or recording scheme to match!
Saturday 9th and Sunday 10th June
If you are in the Museum this weekend you can also come along to the Bat Festival run by the NHM and the Bat Conservation Trust
Saturday 30th June and Sunday 1st July
This is Insect Weekend in the Natural History Museum.We will be celebrating the end of National Insect Week with some special talks and activities
Saturday 4th and Sunday 5th August
Sunday 5th August is also Seashore Day in the Centre for UK Biodiversity, so get beachcombing and bring us your finds.
Saturday 1st and Sunday 2nd September
Sunday 2nd September is also Meteorite Day in the Centre for UK Biodiversity.We challenge you to bring us your meteorites!
Saturday 6th and Sunday 7th October
PLEASE NOTE we will be off site at the AES Annual Exhibition at Kempton Park Racecourse on Saturday 6th October so there will be no identification service in the Museum.
If you are in the Museum on Sunday 7th October Why not come along to our Hedgerow Harvest event in the Wildlife Garden?
Here in the identification service we don’t need a diary or calendar to know what time of year it is, in fact we don’t even have to look out of the window!We can tell the time of year by trends in the enquiries we get by email, phone, through the post or on our forum.
Many species of insect have a lifecycle that lasts for a year, with the larvae or nymphs around in one season, and the adults around in another.Last year we blogged about the amazing bee fly and how it is a sure sign that spring is on the way, but it’s not the only enquiry with a strong seasonal distribution.
I searched our database and the forum for enquiries right back through the mists of time to 1992 to collect data on 3 of our common seasonal species – bee flies (Bombylius sp.), the excellently named cockchafer (Melolontha melolontha) and house spiders (Tegenaria sp.).
These amazing little critters are around in April and May making the most of the spring flowers.The two species we see most often are the common bee fly (Bombylius major, see picture) and the dotted bee fly (Bombylius discolour).They have a fascinating life cycle and you can find out more about them here -
No, we didn’t make that name up, the common English name for Melolontha melolontha is indeed the cockchafer.Although they are beetles they are also commonly called May bugs, and you can see why from the graph above.These large beetles emerge as adults in May or June after living in the soil as larvae for 3-5 years. They are strong though inelegant fliers and are attracted to light, meaning they often fly through open windows and gatecrash evening barbeques!But don’t worry; they are not harmful to humans. Find out more here -
There are several species of common house spider in the UK which are difficult to tell apart.However, they all belong to the genus Tegenaria.They are around all year, but are most commonly encountered between August and October when the fully grown males set out to find love.This is when they are most likely to run out from under your sofa or turn up in the bath – just in time for Halloween! You can find out more here -
On a more serious note this little project shows how the identification service records are a mine of fascinating and potentially useful information.This data also shows that both bee flies and cockchafers emerged significantly earlier in 2011 than 2010, so it would be interesting to see how they fare in 2012 – keep your enquiries and observations coming in to our forum!
Over the last week we've all enjoyed having Nicholas and Olivia with us on work experience in the Angela Marmont Centre, and as one result of their work I've now got loads of great specimen photographs for future blogs, so watch this space! If you fancy doing work experience or maybe volunteeing at the museum, you can find out all about it on our website: http://www.nhm.ac.uk/about-us/jobs-volunteering-internships/index.html So thank you to Olivia and Nicholas for your work and now it's over to you:
We have been lucky enough to work behind the scenes in the Angela Marmont Centre with the UK Biodiversity Team as part of our work experience. Working in the centre has been wonderful for both of us, not only in the fascinating people that we have met but also in the wide range of activities and tasks we have been able to participate in.
On arrival we were shown round the collections and were astonished by the sheer volume of specimens in the archives. We were also thrown into several meetings which were lucky to be able to attend and learnt a lot about how the museum functions, along with scientists time keeping abilities… they tend to get caught up in intellectual discussions.
Throughout the rest of the week we had many other opportunities to get involved. In the laboratories we extracted plant DNA and analysed along with a tour of the lab, only witnessing a fraction of their hugely impressive facilities and machines. We undertook several outdoor activities including surveys in the wildlife garden for the OPAL Project and enjoyed being a part of the Nature Live show.
We were given a hard task of pinning insects and bugs. The specimens were quite old and brittle so our attempts seemed futile as bits of leg and antenna flew across the room. The reason for attempting this was so that the insects looked more alive when it came to setting them in resin for demonstration purposes.
Throughout our week numerous artefacts and creepy crawlies were sent or brought in for identification. We were able to witness and taken part, from beginning to end on the process. For us the most interesting was a fossil brought in by a small boy. To the untrained eye it looked remarkably like stacked starfish, however within seconds the expert Luanne identified it as a stem of a sea lily which lived around 200 million years ago in the Jurassic period.
Perhaps how we spent most of our time was taking photographs of some of the bug and fossil specimens brought in and making sure they had a number for the ease of the system here in the AMC. Of course whilst doing this we saw and photographed some amazing things. There were fascinating and beautiful fossils and minerals, among which was a mammoth tooth trawled in by a fisherman in the North Sea, a necklace made of teeth and tusks and some stone tools found in the Niger.
This is part of the intriguing reply to the person who brought in the stone tools below;
I’ve had a look at the stone tools that you left in the museum. They are all ground and polished stone axeheads apart from one which is roughly fractured stone [...] I believe that ground stone tools first became important in the Neolithic period, which began around 12 000 years ago. [...] However, this does not mean that these specimens are prehistoric in age at all, as ground stone tools are still quite commonly made around the world, both as tourist objects and as working tools for some groups.’
Finally on our last day, in our final hours, we were privileged enough to be shown some of the amazing historical collection, dating as far back as the sixteen hundreds. Sloane was amongst them and we were able to witness his great plant collections, which contain drawings and the first specimens brought back from Jamaica, China and, at the time many other remote unexplored countries of the world. It was very unique experienced and we feel privileged to be among the few who have gained an insight into the histories of natural science and art.
Overall it has been a marvellous week filled with variety and no hour was the same, we only wish it was possible to stay longer.
You only have to browse through the Fossils and rocks forum to see how many of the suspected fossils put on there turn out to be something completely different! Fossil eggs, bones, turtles, ferns, footprints, you name it, natural rock and mineral processes can mimic it. We call these natural rock and mineral specimens that resemble or are mistaken for fossils "pseudofossils". This post doesn't seek to go through the most common look-a-likes, but if you google "pseudofossil" you will find many excellent guides out there.
This post is just some of my personal favourites from the last year. Fun and amazingly co-incidental pseudofossils are one of my favourite parts of my job in Earth Sciences identification.
"Fossil bird head"
It's got everything - neck, beak, even an eye. But this shape is created by the growth of a mineral upon the rock surface.
This shark shape, silhouetted in white against the dark background, would have me swimming for my life if I saw the silhouette peaking out of the sea. But it is just a chance area of cleaner white Chalk against a backdrop of Chalk discoloured by dirt and moss.
I can see what they mean, it looks like a guppy with a long flowing tail and fin. But this is a type of the rock flint known as banded flint. Banded flints form a series of roughly parallel lines such as this, which can create all sorts of misleading shapes. The cause is still not fully understood but the movement of water and silica through the flint is thought to be involved.
The rock flint can mimic any kind of fossil you can think of - bones, eggs, whole heads and bodies, you name it. Look out for a blog all about the wonders of flint coming soon!
"Fossil dinosaur head"
If this were a dinosaur, I can even see what kind it would be - one of the duck-billed hadrosaurs I reckon. Sadly, this is just the shape of the lump of rock, that had probably been exaggerated by weathering.
While writing this I've realised that these pseudofossils do have something in common after all. They all demonstrates one of the key things to appreciate when looking for fossils: don't look for the overall shape of an animal. This is because the soft parts of animals like muscle and skin only fossilise very rarely and in unusual conditions. You can assume you won't come across soft part preservation without knowing what to look for and where to look. To find fossils, look for the hard parts such as bones and shells, and bear in mind these are most often broken, mixed up and/or isolated.
Although we can say what these aren't, the hardest question to answer is, so why did the rock or mineral form or weather into exactly that shape? There are millions of rocks out there and so even if such coincidental resemblences are rare, there will still be plenty of pseudofossils. And of course those are the rocks that are going to catch your eye and get picked up.
So what should you look for? This page on our website has some good information and links for fossil hunting advice. And of course we will be happy to see whatever you find, whether rock, mineral or uncannily-vegetable-shaped-rock on the rock and Fossil forum here.