Complex sentence: Extending upriver from Mont Clare along the Schuylkill, this series of "steep cliffs and deeply etched ravines" are formed by the intersection of hard Lockatong argillites with the river.
Split into simpler sentences: Extending upriver from Mont Clare along the Schuylkill is a series of cliffs and ravines. These geologic features are formed by the intersection of hard Lockatong argillites with the river.