I had just turned off State Route 129 onto the small road running beside the river when I saw what I had come to find: a large, strange-looking basalt structure projecting from the canyon wall. I had read about lava dikes for years, and suddenly one was standing in front of me.
There were three large rock structures projecting upward along the canyon wall. These were three remnants of that eruptive event. I was trying to comprehend what had happened. These were remnants of the Chief Joseph Dike Swarm.
Earlier lava flows had covered the region in broad sheets of rock. Later, pressure from below cracked those existing layers. Liquid rock rose through the cracks and spilled onto the surface, which at that time lay hundreds of feet above the present river.
Eventually the eruption ended, but magma remained inside the fissure. That rock cooled from its sides toward the center. In the largest exposure, I could see the dike itself and the differently oriented columns beside it. The scene created a spectacular photograph.
The rock in that ancient fissure tends to be harder than the surrounding colonnade formations. As the region uplifted, the river eroded this valley, exposing some of that more resistant basalt. I put my binoculars on the east side of the large one. There it looked like a double row of cord wood stacked. I wished I could hike to it and touch that crystalline formation.
Yellow Warblers called from cottonwoods beside the river, as I climbed back into my car to run across the bridge. There, we could look back upstream. From a distance, the structures stood out even more clearly. I could see the dikes projecting from the landscape and imagined liquid rock rising through them millions of years ago.
Great trip, wonderful descriptions!