[3] The Urnetoppen Member, which is approximately 30 meter thick in the Hornsund area, consists of greenish shales, siltstone and fine-grained sandstone, occasionally with clay-ironstone nodules.

[2][4] The top of the Urnetoppen Member contains the so-called Brevassfjellet Myalina beds, a 5–6 meter thick, fossiliferous conglomerate.

The locally developed Skilisen Retzia Limestone belongs to the uppermost part of the Wibebreen Member.

[2] Fossiliferous layers of the Vardebukta Formation are concentrated to the uppermost part of the Urnetoppen Member (Brevassfjellet Myalina beds).

These Dienerian aged beds have yielded the bivalves Myalina and Anodontophora, crinoids, conodonts, numerous isolated fish remains, and trace fossils.