Extrusive Igneous Rocks Courtesy of the USGS Basalt is a black volcanic rock that forms when lava cools on the surface.
(Extrusive Igneous Rocks Courtesy of the USGS Basalt; is; a black volcanic rock that forms) (a black volcanic rock; forms; T:when lava cools on the surface) (lava; cools; )
Extrusive Igneous Rocks Courtesy of the USGS Basalt a black volcanic rock lava
is forms cools
a black volcanic rock that forms
T:when lava cools on the surface