These rocks have recently been dated between 539 and 618 million years old Black and others, 2007 and are now considered to correlate with the New River and Mascarene terranes of southern New Brunswick, Canada. Although originally they were igneous and sedimentary rocks such as basalt, sandstone, and shale, the eastern formations have been metamorphosed into greenstone, phyllite, argillite, schist, quartzite, and other foliated types. In addition, many folds and faults have bent and broken the formations in rather tortured-looking outcrops. One such fault can be seen at the north end of Pettes Cove, where it separates metabasalt of Swallowtail Head from schist of North Head.