undifferentiated rock units

Paleontology and geology

During the Devonian, Maine was situated in the tropics, south of the equator. The collision of North America with Avalonia that began in the Silurian continued into the Devonian, greatly increasing the geographic extent of Maine. Volcanism, uplift, and significant erosion and sedimentation were all associated with the collision. The fossiliferous deposits in Maine from this time represent a variety of habitats. Nearshore marine settings were dominated by brachiopods, although bivalves, corals, crinoids, conodonts, gastropods, ostracodes, and trilobites were also present. Brachiopods also dominated the deep-water basins, but occasionally graptolites and trace fossils are found. Fully terrestrial habitats existed as well, and fragmented plant fossils have been preserved in a few rock units.