A south-trending belt of sialic Paleozoic rocks on the northern coast of Ellesmere Island lines up with the Lomonosov Ridge. It was deformed (1) in Middle Ordovician or earlier time, (2) between the Late Silurian and the Middle Pennsylvanian, and (3) in the Tertiary. The Paleozoic movements elevated terrane continuous with the Lomonosov Ridge relative to terrane on the east, but the Tertiary movements did not cause such relative uplift. About 40 km inland, the south-trending orogen terminates against east-trending structures, that conform with the predominant structural grain of northern Ellesmere Island. The zone of structural intersection, marked by Early Devonian (or older) ultrabasic intrusions and a Tertiary graben, was repeatedly a site of crustal extension.

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