Columnar structure
| (Geol.) | a structure consisting of more or less regular columns, usually six-sided, but sometimes with eight or more sides. The columns are often fractured transversely, with a cup joint, showing a concave surface above. This structure is characteristic of certain igneous rocks, as basalt, and is due to contraction in cooling.-> |
| See under Columnar. |
See also: Columnar, Structure