trachyte-dolerite

Updated: January 20, 2026

If we then take a rock of intermediate composition, such as that prevailing in the Peak of Teneriffe, which Abich calls Trachyte-dolerite, its proportion of silica being intermediate, or 58 per cent, it weighs 2.78, or more than trachyte, and less than basalt.

Sir Charles Lyell - The Student's Elements of Geology