Nautiloid fossil with fine ribs, Triassic? Jurassic? No idea

[rocket]

we have got an unusual nautiloid, approx. 4 cm, not compressed, unusual matrix with lot of fine fragments (like Quarz?)

fantastic ribs, both ways, crossing

Comes from an old collection and might be Germany or Austria, the collector did not buy much

Might be someone has a good idea...

thanks!

[M Harvey]

Beautiful specimen.  

[Darktooth]

Is this possibly a gastropod instead of an nautiloid?

[jpc]

59 minutes ago, Darktooth said:

Is this possibly a gastropod instead of an nautiloid?

Based on the first photo, I would say ... not a snail.  

[rocket]

definitely not a snail, Nautiloid.

I found a second one in the old collection, preservation is similar. Will add some pics the next days