Jurassic Bone Block ID? (Yorkshire, UK)

[Paleoworld-101]

Hi all, I recently found this massive bowling ball sized rock at Saltwick Bay near Whitby on the Yorkshire coast (Northern England). It is lower to middle Jurassic, i think about 180-170 million years old (possibly the Whitby Mudstone Formation). As you can see it it's full of various bones, which occur on almost all sides of the rock so they are probably running right through it. Prep for this one is going to be a nightmare i can tell and i don't have the right tools, but for now i really just want to try and figure out what i've got. I think it's fair to assume the bones are associated. The options for this bit of coast are fish (Gyrosteus), ichthyosaur, marine crocodile, plesiosaur or dinosaur. 

 

I was hoping based on the cross sectional shapes of some of the bones, and the texture of the bone itself, someone would be able to narrow down what it might be. Fish or reptile would be the first thing to determine. My obvious first assumption was marine reptile, but some of the fish on the Yorkshire coast like Gyrosteus are also huge (5m long) and i'm not very familiar with their bone structure. 

 

 

 

In this picture, i thought the rectangular bone towards the bottom might be a vertebra in cross-section. If so, from what? Could it be the edge of an ichthyosaur vertebra before it dips down in the centre?

 

 

 

 

 

This bone is the biggest in the block, about 8 cm long and 3 cm thick. 

 

 

 

Continued in the next post!

 

 

 

[Paleoworld-101]

Final photos. 

 

 

 

 

 

Any help is appreciated!

[jdp]

I think this is plesiosaur based on the histology.

[fossilized6s]

Thats neat! Are you able to prep this? 

[LordTrilobite]

Cross sections like this can be very suggestive in shape. My thinking is that prep is needed for any good ID.

[JohnBrewer]

2 hours ago, LordTrilobite said:

Cross sections like this can be very suggestive in shape. My thinking is that prep is needed for any good ID.

I agree. 

[Paleoworld-101]

As Jdp suggested, couldn't the bone histology be used to indicate anything? They are effectively thin-sectioned after all. I agree though a more specific ID will require prep. At this point I mainly just want to determine if it's big fish or reptile (I'm thinking the latter). 

 

@fossilized6s currently no, I don't have an air chisel/scribe, but I'm wanting to get one 

[LordTrilobite]

1 hour ago, Paleoworld-101 said:

As Jdp suggested, couldn't the bone histology be used to indicate anything? They are effectively thin-sectioned after all. I agree though a more specific ID will require prep. At this point I mainly just want to determine if it's big fish or reptile (I'm thinking the latter). 

 

@fossilized6s currently no, I don't have an air chisel/scribe, but I'm wanting to get one 

Oh yes, looks like reptile. Further than that I cannot tell.

[Troodon]

I'm in the reptile camp but I would leave the block alone, it's very interesting the way it stands today.