“I only went out for a walk, and finally concluded to stay out til sundown, for going out, I found, was really going in.” John Muir 1913
The city of Tucson sprawls on flatland that’s surrounded by individual ranges of mountains. They poke up like islands floating on a desert sea. Geologists say the mountains once rose higher and the desert was much lower; but erosion wore the rock away and placed it on the lowland, so today the reduced mountains appear to float.
High above Tucson to its north, a fist rises skyward, and on the fist, a finger points straight up. A trail heads toward it, and today I walked a steep canyon for a closer look.
Many saguaros line the way but far fewer than are shown in old pictures taken before 1940, and scientists used to wonder why. They suspected it had to do with a cold snap in 1939 when the temperature remained below freezing for at least twenty-four hours, something saguaros die from. Or maybe it was from some activity of people that conservationists insisted must change. So they launched a study with lots of post-war money.
I live, unwisely, in earthquake country, where bridges are made strong. We have strong medicine against cancer, and strong science to preserve the saguaros. Our defenses are indeed strong; but time and nature win in the long run. Geology teaches patience and inevitability; I love its theories. But I think even geology is ready for upheaval. It is like physics was before Einstien—ready for a better theory. I will deal with this in a later post.