Erratic boulders, petrographically similar to the volcanics exposed around Kap Washington, are found on islands and along the coast much further to the east. Isotopic measurements on two such boulders show that these volcanic rocks are of the same age as the Kap Washington volcanics. The regional distribution of
the erratics supports glacial morphological evidence for a major Weichselian ice flow moving eastwards along the coast of North Greenland.