???? fossil

[drbush]

Hi friends, can you help me with this? I went to Al Hasi city, Sulaiy formation ( Berriasian) , Cretaceous  , to the north of Riyadh and found this strange  fossils. It was a surface find; it is 4 cm long, 3 cm wide, concave . The outer face is smoth , the inner surface is semicircular and smooth , In the past i found smilar fossils, Cretaceous but differnt formation (Aruma) but larger and in layers (one inside the other ) photo 2 . So what could it be?

[Pemphix]

Septic-chamber of  a Nautilid.

 

[drbush]

Is it this? And is this the? foramen indicated with the red arrow ? 

[drbush]

this looks like it 

[Pemphix]

5 hours ago, drbush said:

Is it this? And is this the? foramen indicated with the red arrow ? 

 

3 hours ago, drbush said:

this looks like it 

Yes, that is what i think it is...

[Ludwigia]

What's behind the foramen is called a siphuncle.

[drbush]