I like to come here early in the morning. Sometimes, arriving before the wind awakes, I catch reflections of the surrounding mountains. Beyond the low bench of Logan Pass the Garden Wall begins, running northward with the Divide. In the eastern valley the pitched peak of Going-to-the-Sun hunkers in the morning light like a tensed warrior. To the south, the incisor Bearhat, beautiful cloud cutter of Hidden Lake Valley, juts above the nearby saddle of the pass. But over this place, standing as fresh monuments to an age of ice, tower the cliffs of Clements and the pyramid Reynolds. I am sitting on a wedge of red rock. Its surface exhibits a wrinkled pattern identical to the ripples in the soft mud of the shallow pond. The distance is not great; with a stick I could reach out and touch the mud. Yet this represents a gulf no bird can fly, for between the ripples of this rock and the ripples of this mud lie billions of vanished mornings, a constellation of years. These red, green, tan, white, black and purple bands of rock that layer Glacier’s mountains comprise the oldest unaltered sedimentary rocks on Earth. They were laid down in Precambrian time, more than a billion years ago, when life was just beginning, as the deposits of an inland sea. For millions of years, sand, mud and carbonates washed into the ancient sea, compressing the lower layers into mudstones and limestones, building up a sediment thickness that may have been as much as 10,000 meters (_see_ metric conversion table on page 136). When we look at the sharp contours of Glacier’s mountains, we see the evidence of uplift, overthrust and glaciation. But on the geologic clock these are recent events, a mere eyeblink of time ago. For the vast majority of years, the rocks lay undisturbed and level beneath the sea and land. To understand better the tremendous time scale these rocks represent, we need a way to visualize the vast collection of years. If we were to make a movie of these geologic events, we would first need to determine how many years each minute should represent. Since the Pleistocene lasted about 3,000,000 years (its four ice ages sculpting the present muscle of this land), let us make each minute portray a million years. To chronicle these rocks we will then need a film 60 hours long! Not until the fifty-seventh hour of our film will the Mesozoic lowlands begin to bulge with the coming Rocky Mountain chain. During the long preceding hours we would have seen little else but sea—withdrawing, advancing, deep and shallow; yellow, green, and brown with great colonies of algae. Unseen below the water, lava has spilled out occasionally on the sea bottom; once, it intruded between the rock layers below, forming the conspicuous, 60-meter-thick band of black diorite that we see today on many mountain faces in Glacier.