It is possible that much of the west coast of North America is comprised of terranes attached like this. Extrusive Magma reaches the surface and cools rapidly. The primary type of rock is basalt from cooling lava. The primary extrusive volcanic landforms are volcanoes. Shield volcanoes are created by non-viscous lava and have broad, gentle slopes.
Composite volcanoes hare from more viscous material and are steep sided cones.
Another volcanic landform is a cinder cone, made from individual pieces. Lava plateaus, with visible cliffs revealing different strata, also occur where non-viscous lava does not create a slope. Other features are craters at the top of volcanoes and calderas formed when the top of a volcano explodes away. Intrusive Magma does not reach the surface and cools gradually, A primary rock type is granite, with larger crystals than in basalt. The largest intrusions are batholiths, which are revealed by later uplift and erosion.