Technically speaking, the peaks in Forillon National Park are part of the Canadian Appalachians, which are a subrange of the Appalachian Mountains. They may also be classified as part of the Notre Dame Mountains, which is a subrange of the Canadian Appalachians.
The topography in the region formed as a result of multiple mountain-building events, including the Taconic, Acadian, and Alleghenian orogenies. Of all these mountain-building events, the Acadian orogeny arguably had the largest impact on this particular region as it caused the accretion of continental fragments to the supercontinent of Laurentia and the formation of large folds that are present on the peninsula to this day.
There are ten distinct geologic formations in the park alone, including different layers of limestone and sandstone that date back to the Devonian, Silurian, and Ordovician periods. The park is also home to an extensive collection of fossils. These fossils are several millions of years old and bear witness not only to the evolution of life on earth but also to the movement of tectonic plates. Strangely, none of the 6 park rangers and assistants I spoke with knew exactly where too find any fossils!