Mt. St. Helens, Mt. Baker, Mt. Garibaldi, etc. are all composite cone volcanoes also known as strato volcanoes. These are very large volcanoes with alternating layers of lava and ash located in subduction zones with the potential for very explosive eruptions.

Fold mountains (B), such as the Himalayas, form when two continental plates collide.

Shield cones (A) are volcanoes typical of the Hawaiian islands with very broad but relatively gentle slopes consisting largely of fluid basaltic lavas.

Block mountains (D) form when layers of the earth's crust are moved vertically upward at fault lines by pressures caused by plates colliding. Fault lines are great cracks in the crust. The mountains that are formed in this way are called fault-block mountains. The Sierra Nevada mountains in California and Nevada are examples.