Here's a breakdown:

* Subduction: This is a geological process where one tectonic plate (the Juan de Fuca Plate) slides beneath another (the North American Plate). As the denser oceanic Juan de Fuca Plate dives under the continental North American Plate, it melts.

* Magma Formation: This melting creates magma, which is less dense than the surrounding rock. This magma rises and accumulates beneath the surface.

* Volcanic Activity: The accumulated magma eventually erupts through the surface, creating volcanoes. The Cascade Range is a chain of these volcanoes, formed over millions of years.

* Mountain Building: The volcanic activity and the pressure of the subducting plate also contribute to the uplift and folding of the Earth's crust, forming the mountains that make up the Cascade Range.

So, in essence, the Cascade Range is a product of the continuous process of subduction, where the Juan de Fuca Plate dives under the North American Plate, leading to volcanic eruptions and mountain building.