premise: The crust can be divided into ocean basins, underlain by a thin layer of dense, basaltic rock, and continents, formed of a much thicker but less-dense layer of granitic rocks.
hypothesis: Gabbro is a dark dense rock that can be found in the oceanic crust.
hypothesis_graph_structure: Gabbro<>is<>a dark dense rock that can be found in the oceanic crust$$$a dark dense rock<>can be found<>in the oceanic crust