This is a matrix with 4 very nice devonian shells:

Name : 2x BELLEROPHON vasulites (Montfort)
1x PALAEOZYGOPLEURA KAUPII (Goldfuss)
1x MURCHISONIA SP.
Age : mid. Devonian , Eifelian
Location : Sötenich , Germany

The matrix has a size of 4.7 x 3.3 cm.
I've got that shell from an old collection .Those shells are rarely offered for sale.Many were found only into the Sötenich(Germany) location.