Martha McPhee finds that the drive up the San Andreas Fault "beats the hell" out of Interstate 5

For as long as I can remember, my father has been explaining the world to me, taking it apart and putting it back together like a puzzle. He speaks in deep time, millions and billions of years, and as he speaks, great mountain ranges rise and disappear. Continents drift together and pull apart and drift together again in fast motion, as if kneaded into one another like bread—subducted, consumed, they vanish, or just as easily they amass and form one supercontinent. There was Pangea, whose name means "goddess of the earth" or "whole earth," and before Pangea there was Rodinia, whose name is Russian for "homeland." When Rodinia broke up, Iapetus, the ancestral Atlantic, formed. Iapetus, father of Atlas. The seemingly static land we live on is instead very much alive. The gentle Appalachians not far from our town in New Jersey were once as high as the Himalayas. Our house was built on an ancient lake formed during the extensional events more than 200 million years ago, when Pangea was pulling apart to make the Atlantic Ocean. The lake lasted eight million years. My father doesn't take anything for granted. He wants to get to the bottom of things.

When I was a child, deep time and the elasticity of the land scared me. The possibilities were overwhelming—vast and incomprehensible. In a hundred years, we'd be dead. In some fraction of a billion years we'd be utterly dead, extinct, and even our New Jersey would be swallowed up by some gigantic landmass. For all I knew, it could somehow become part of the moon. But when my father pulled over by the side of the road to dissect a road cut, or when he showed me on a map how Staten Island had once belonged to Europe and the Hebrides to Canada and India to Madagascar, mostly I was fascinated by the stories he could see there, because I could not see them at all.

In December, once again I found myself by the side of a road with my father. We were with my husband, Mark, in San Bernardino, California, near a grove of grapefruit trees thick with ripening fruit, smack in the middle of the San Andreas Fault Zone. To be exact, we were standing at the juncture of the north and south arms of a bifurcation in the fault. We were on our way north 450 miles to Point Reyes, and we planned to travel the distance on the fault for several days, ending the trip in nearby Napa Valley, on a daughter fault, for a New Year's Eve feast at the French Laundry. Above us loomed the San Bernardino Mountains, rising 11,000 feet. In the distance the San Gabriels shimmered. These mountains, the Transverse Ranges, run east–west and were raised by a bend, the Big Bend, in an otherwise straight fault. We were here to read the land, and that's what we were doing, looking for evidence of the fault on the fault, trying to find the stories. It was a clear California morning, though very cold. Across the street stood a humble yet welcoming wooden gate—the entrance to Rancho San Andreas North.