The Sinsk Formation is a geologic formation in Central Siberia, Russia, exposed along the Lena River.
It preserves fossils dating back to the Botomian stage of the Cambrian (corresponding to Cambrian Series 2).
It notably contained the Sinsk Algal Lens, a Lagerstätte which preserved some soft-bodied animals that would not typically be preserved as fossils.
[1] However, the Sinsk Algal Lens has largely been destroyed by commercial fossil collectors.
This article related to the Cambrian period is a stub.