Chapter 17 THE ORDOVICIAN AND SILURIAN

[Footnote: Often known as the Lower Silurian.]

THE ORDOVICIAN

In North America the Ordovician rocks lie conformably on the Cambrian. The two periods, therefore, were not parted by any deformation, either of mountain making or of continental uplift. The general submergence which marked the Cambrian continued into the succeeding period with lit