Basalt

earth’s crust rested directly upon a molten sea of basalt 58:5.3-4

seafloor basalt is a form of lava heavier than granite, and that makes the seafloor heavier than land masses, and thus sunk 58:5.6

The Palisades of the Hudson River were formed by the extrusion of basalt lava between these Triassic strata. 60:1.3