In some of the experiments 300 pounds of shot were piled over a cloth layer on top of the strata to imitate the weight of natural sediments. This was before injection of the hot wax, and the result was a neat dome of deformed layers at the surface, a domical hill over a lens of wax inside. This hill was eroded with a spray of water to show what kind of radial valleys would form. Such radial streams were found in South Dakota, with infacing escarpments, around some of the dome hills made by laccoliths. From the beginning it appeared that a lens of injection would form, that the strata would arch over a dome of wax. The arched strata stretched on the crest and the breaks gaped upward, while the side bends cracked gaping downward. It was there that the wax could break its way upward and make a volcano. Some nice little experimental volcanoes of wax-built cones and craters formed on top of the model. As with all folded strata arched downward under weight, the cracks on the bend of a downward arch, or syncline, admit lava from below, whereas the cracks on the upward arch, or anticline, are held tight, closed by the weight of strata above. Thus an intrusive dome will not erupt through its crest, but through its sides. The results of all these tests showed that rigid beds carried the arching force and that soft beds were most invaded and pushed aside by the wax. The steepness of curvature of arch varied with the load. An inclined pipe formed an irregular lens thickest away from the incline. In a hard bed ruptured on a downbend, concentric fractures around a dome let the lava up to higher strata. On the crest of a hard bed the fractures are like the spokes of a wheel, but they do not make dikes; they yawn open upward. Liquid wax tended to spread as a thin sheet in soft layers of strata, stiffer wax tended to arch up in a steeper dome. Rapid injection made a higher and smaller dome than slow injection. Compared with the arching up the whole long mountain oval of the entire Black Hills dome, with granite on the crest, this intrusion of wax only imitates the small domes of lava intrusion or injection, where the injection carries the energy or stress. Indeed, in nature, even the lava lenses are influenced by the buckling that is going on in the strata under stresses of crust warping. For the warping crust of the earth is always pulling the trigger and straining the strata. The lava rising from below seeks out the weak places and assists the buckling, as well as following the most incoherent mud or shale beds.