Myself and my two boys look for fossils at mappleton regularly.
We find crynoids, belemnites and ammonites but this has me puzzled.
It looked like an egg encased within the rock. I managed to retrieve it in one piece.
Any ideas? The rock was perfectly formed around it.
Dans right it is a nodule and could contain a fossil but not a cannon ball nodule, cannon ball nodules (Jurassic) come from bed 33 cannon ball doggers near Whitby but are found on the Holderness because of the last ice age and rocks and fossils being transported inside glaziers and deposited when they melted.
I have found similar nodules that contained coprolites and looking at the matrix could have come from Speeton (Cretaceous) but it's hard to tell.
Found Speeton ammonites in similar martix.
Near enough, Dan.
It is a concretion. That word covers a range of different types of object, but they are all the result of local chemical changes (sometimes with physical changes) in the rock.
Think of rain drops as an analogy. Given supersaturated air, water will try to condense out of it, and it will start to do so using particles of dust/pollen/etc as a nucleus. Once a rain drop has formed, the air around it will be less saturated; the system will be in better equilibrium, so the raindrop will persist.
Back to the rock: Since the sediment was deposited and turned to rock (or at least since the sequence of events leading up to rock had begun), the physical and chemical environment changed, for instance due to burial by other sediment and/or by heating. That state of disequilibrium caused chemical and physical processes to rearrange the material comprising the rock (minerals/molecules/elements being altered and moved). Such changes often use fossils as a nucleus, growing outwards and enveloping the nucleus in a volume of rock of somewhat different chemistry. That, in outline, is a concretion. A concretion may grade gradually into the surrounding rock, or it may, as in your example, be relatively distinct (and hence physically separable). They can also show concentric layering, which you can see to a small extent in yours: there is a bluish-grey halo around the discrete concretion.
Although the words concretion and nodule are often used somewhat interchangeably,
"There is an important distinction to draw between concretions and nodules. Concretions are formed from mineral precipitation around some kind of nucleus while a nodule is a replacement body."
(from the link below)
Canonball concretions are a common name for these things in some places. There are many other common names. Bowling Ball Beach in California gets its name from the conretions on the shore (see the first photo here - http://en.wikipedia.org/wiki/Concretion).
Your example looks a bit like what are called Moqui marbles in Utah (see same link)
Some types of concretion have mineral veins dividing them into numerous chunks. These are called septarian concretions (commonly also septarian nodules, which is less correct). There is a hint of that in your specimen - note the short pale mineral veins (probably calcite or quartz).
Septarian concretions are also discussed in that link.
I can't see a fossil at the core of your concretion. It may still be within it, or it could be too small to see unaided, or something else might have acted as the nucleus (eg. an particular mineral grain), or there may simply not have been an obvious nucleus.
You'll find concretions in other discussions on NaturePlus, eg:
It's good to find something new and a bit different.
Also managed to find the biggest belemnite we've ever come across at about 10cm.
Productive afternoon all round.
New I had one somwere!
Found on the Holderness Coast a long time ago.
I will give it a 'tap" with my hammer and see what's inside tomorow.
Let's have a look at the Belemnite please, it could be Jurassic (Whitby area) or Cretaceous (Speeton area)
I've attached more of the weekends finds including the concretion after removal.
The ammonite seems to be formed entirely of fools gold. This is the third we've found of similar size and formed in the same way.
Your first specimen looks to be a Belemnite called Acrocoelites sp from the Jurassic of Whitby.
You also find some big Belemnites from Speeton (Cretaceous) that are very similar.
Your second specimen is probably Kimmeridgian, the ammonites you find on the Holderness coast in the 'black sand' usually don't rot and will always look spectacular.
Another nice find.
I have attached a couple of images of the black (pyritic) sand from the Holderness that I have found ammonites and other very small fossils inside.
Your third image shows some partial Belemnites, it's hard to explain what they are but I can see a partial Neohibolites minimus from the Cretaceous of Speeton.
To the left hand side of the image are ossicals, they make up the stem of a sea lilly.
More nice finds.
Here's a picture of an even smaller one my 13 year old found Mike.
Also a rock I split and a large part of an ammonite too. All found at Mappleton.
You don't have to look too hard on the Holderness to find a partial outer whorle of a big ammonite like in your first image.
Looks like a partial hetromorph from Speeton.
Another nice find.
Your second image is an ammonite called Kosmoceras from the Callovian of the Middle Jurassic, i have found a few of these but the sediment has not really formed into rock and is very fragile when the specimen has dried out, so you have to be very carefull with it.
Another very nice find, well done.
Nearly forgot Nobby I have split my 'egg' tonight and although i was dissapointed there did not look to be anything inside when i took a closer look i could see a fossil, probably a gastropod about 2mm across.
Thanks tabfish. I've been telling the boys about our finds and it's made them even more keen to get out there and finding more.
Thanks for all the information. I'll be sure to post some pictures of our next trip out.
Good luck Nobby I hope you find a bagfull!
Go a bit further affield and don't stick to Mappleton, weigh up the wind, tide and feel how the Holderness works.
Encourage your lads like I have encouraged my 5 lads to enjoy and take part in nature.
Sorry to go on Nobby but don't just look for fossils were you find the pyritic ammonites, as I said things of a similar density settle in one place especially artifacts that have washed out of the boulder clay.
It's great to get some feedback thanks tabfish. We generally don't look on the ground. All our finds mainly come direct from the boulder clay face. We like to go after a storm if we can to there's a fresh face to scour.
The boulder clay cliff is still a good place to look but when the cliff collapses the clay dissolves in the sea water and rocks, minerals and fossils are deposited on the beach.
Unfortunately they are in a high energy zone and only last for so long before nature starts to take them back.
Forgot to add under the sand on the beach is far more boulder clay than in the face of the cliff, so when the beach is stripped of sand and you are walking on the clay keep your 'eyes out' if you know what I meen.
Another 'egg' that I gave to someone because they thought it was from a Dino.
It made there day! even though I tried to tell them what it was.