Smith Rock State Park years ago, a large caldera was formed when overlying rock collapsed into an underground lava chamber. This created a huge amount of rock and ash debris that filled the caldera. That material solidified into rock, becoming Smith Rock tuff. Rhyolite flows intruded along faults in the Smith Rock Tuff. A half million years ago, basalt lava flows from nearby volcanoes covered the older tuff. More recently, the Crooked River cut its way through the layers of rock to create today's geographic features. Smith Rock itself is a -high ridge (above sea level) with a sheer cliff-face overlooking a bend in
Lava gains a solid crust on contact with the water, and this crust cracks and oozes additional large blobs or "pillows" as more lava emerges from the advancing flow. Since water covers the majority of Earth's surface and most volcanoes are situated near or under bodies of water, pillow lava is very common. Because it is formed from viscous molten rock, lava flows and eruptions create distinctive formations, landforms and topographical features from the macroscopic to the microscopic. Volcanoes are the primary landforms built by repeated eruptions of lava and ash over time. They range in shape from shield volcanoes with