The stromatolite fossils appear wavy and dome-shaped, are typically high, and were found in iron- and magnesium-rich dolomites that had recently been exposed by melting snow. The surrounding rocks suggest that the stromatolites may have been deposited in a shallow marine environment. While most rocks in the Isua Greenstone Belt are too metamorphically altered to preserve fossils, the area of stromatolite discovery may have preserved original sedimentary rocks and the fossils inside them. However, some geologists interpret the structures as the result of deformation and alteration of the original rock.