?

What is that on the very lower left of the second pic?  Could the whole chunk be a dried-up lake bottom, or the like?

Looks like a concretion with dry cracks.  They are occurring in various deposits and are often mistaken for fossil turtles... (go figure).  

Thanks for the input Trig - Nick there not cracks they protrude ie are raised above the rock surface, they are very solid and stand appart from the rock in texture and color, yet there are what look to be small bivalves on the surface of the rock and other small stuff ive never seen in  the jurassic stuff i find. 

Okay, I see now.  They appeared to be sunken in at first glance.

Its got me stumped mate the pattern links up on both sides i don't think they can be worm burrows or bryzoa and i can't see how they could be roots.

The cracks later filled with a harder mineral, which now protrudes......  trust me, a common occurrence, not a fossil....   Google it.  (see also Septarian nodules)

The cracks later filled with a harder mineral, which now protrudes......  trust me, a common occurrence, not a fossil....   Google it.  (see also Septarian nodules)

-trigonictis

The cracks later filled with a harder mineral, which now protrudes......  trust me, a common occurrence, not a fossil....   Google it.  (see also Septarian nodules)

-trigonictis

Heres a pic am i right in thinking the concretion would run through the rock on a septerian nodule?

Ps Trig i was convinced it was a septerian nodule after your post, the pic shows it as such! but if something wraps a rock with fossils in it i now think this is a fossil what do you reckon ?

I still think it's just a nodule.  Even if the cracks don't go any deeper, there could have, at one point, been a cracked outer layer that is no longer there.  Not a fossil.

Nick mate its a rounded rock, with a lot of fossils on it the question asked is what is the pretruding patern that ive now shown runs on the rock not in it, ime feeling a little pissed as u say over there, as i have just in my opinion destroyed a piece of a complete fossil to answer my origional question. Nick ive very recently burrowed as carfully as i could knowing i realy should not have, into the rock beneath the segment i removed, it is the rock below not the concretion, fossil, bulbouse stain !

People freinds i hope you undestand  ime not arguing for arguing sake this can not be a septerian nodule, the minerals that make up the predruding pattern that nets this fossil rock is far softer than the rock it covers,and definatly does not run through it !

I still think it's just a nodule.  If a fossil-filled (which it obviously is) clump of mud was exposed to the air, it could have gotten a cracked surface.  The inside of the cracks could have crystallized.  After the cracks crystallized, the outer, softer, surface could have eroded away, leaving the raised crystalline structure.

It is understood that the rock is solid, but there are many types of nodules and concretions, which is what I think this is...a fossiliferous nodule that has neat crystalline patterns on the outside.  The rock itself is not a fossil, in my opinion.

I suspect that the key, or at least a key, to the rock/pattern identity is in this area - although without seeing in under a scope I can't say anything about it.

I'll say this much: it looks industrial.

To all who kindly had a say in this and i hope still do, i contacted the geologists helping me and sure enough septerian nodule was the answer i was given. so it looks ive got over exited? but i did explain the same as stated on my earlier posts ie the mineral patern does not apear to run through the rock, if this was the case i was told there too stumped. but i do now know the rock contains black crynoid stars related to star fish and a lot of other smal jurassic fossils i don't normally find in the jurassic rafts i dig out of the gravel beds.
I aim to carfully crack it open tomoz to see if like Nick says is indeed right, becouse the mineral trace should be aparent inside the fresh rock. Again thanks for the input i realy need it !  ps if i start pixxing people off just p message me and give me a bollocking i can take it ask Don !

I suspect that the key, or at least a key, to the rock/pattern identity is in this area - although without seeing in under a scope I can't say anything about it.
I'll say this much: it looks industrial.

[image]

-adocus

Just found this piece on the google its got a lot of the same, although the individual fossils are a lot larger by the look?

There are a lot of fossils in your specimen.  Nice piece.

There all over it Nick i just don't understand why ive never seen these on the large fossil jurassic slabs i find is it a different time period or enviorement?