DID YOU KNOW? That this dike in Horseshoe Gulch has horizontal columnar jointing? Normally, one finds columnar jointing in lava flows where it is usually vertical. The columnar joints are interpreted to form normal, or at right angles, to the isotherms (lines of equal temperature) in the molten material during cooling and solidification. In lava flows, the isotherms are generally horizontal, get...ting cooler toward the atmosphere on top of the flow. So, the columnar joints that form at right angles to the isotherms are vertical.
In the dike, the rock into which it intrudes is cooler. So the isotherms are vertical (parallel to the walls of the dike) and the columnar joints that form at right angles to the isotherms are horizontal.