Orsten Stones

[oilshale]

Orsten Web Site

The term 'Orsten' has been applied to horizontally laminated limestones nodules. These occur embedded in/surrounded by Alum Shales of the upper part of the Cambrian in Sweden (now uppermost Middle Cambrian, formerly: zone 1 Agnostus pisiformis, to the Furongian, and here the former zones 5/6 Peltura scarabaeoides of the UC sequence)(zones 3 and 4 did not yield any 'Orsten' fossils).

'Orsten'-type fossils other than the ones mentioned above are likewise 3D-preserved phosphatized microfossils, which may range from embryonic stages (e.g., early cleavage stages, as occurring in various late Precambrian to Lower Cambrian rocks, but also much further developed egg stages, such as that of the putative nemathelminth Markuelia) to arthropods in much younger sediments.