Remarkable Preservation of Microfossils and Biofilms in Mesoproterozoic Silicified Bitumen Concretions from Northern China

Figure 1

Generalized stratigraphy of unit 3 of Xiamaling Formation (a), representative photographs of the bitumen concretions embedded in black shales (b) and green cherts (c), the ellipsoidal or pie-like concretions (d-e), and the bitumen layers sandwiched between the black shales (f) and green shales (g).