In places, the rock is incredibly dense and has to be slowly broken apart. This
Detailed Description
In places, the rock is incredibly dense and has to be slowly broken apart. This dense rock is interpreted by HVO geologists to be some of the last lava that erupted and solidified within the fissure 8 channel. USGS photo by C. Parcheta, 08-07-2019.
Sources/Usage
Public Domain.