undifferentiated rock units

Paleontology and geology

Mainland Nunavut was above sea level in the Devonian, and shallow to deep waters covered the Arctic islands. Ferns and lycopsids (scale trees) grew near the coast, and pollen and spores from these plants were carried out to sea along with sediments eroding from the land. The shallow waters close to shore were home to a tetrapod-like lobe-finned fish, while the somewhat deeper waters harbored other types of fish, like agnathans (jawless fish) and osteostracans (armored jawless fish). Stromatoporoids and corals built up reefs, which were home to molluscs, brachiopods, sponges, trilobites, graptolites, and conodonts. By the end of the Devonian, another continental plate collided in the north, folding, faulting, and altering rocks in some of the islands. This activity also pushed up some areas and dropped down others.