a mountain lake surrounded by sheer cliffs spills down the page. three vertical columns depict water rushing between tall pines and splashing over rocks

three panels. the river leaves the mountain, winding sedately into a meadow. cream-and-orange fish swim between swaying fronds of seaweed. a closeup of smooth river stones, wreathed in white foam

three panels. a diagram showing how a river erodes its banks. an old map of the river's course. a landscape--steep striated rocks and orange brush as the river enters a canyon

canyon walls span the page, a crack of light between them. marine fossils dot the rocks. dark green water surges across the bottom of the page and a single fossilized oyster is highlighted

a single scene, underwater. green light filters in from the surface as trilobites swim through tall seaweed. a single living oyster is highlighted

six columns. an oyster spawning a cloud of eggs into dark water. as time passes, seaweed grows up around the oyster, and it gradually becomes covered in barnacles

a shattered oyster shell, half-buried in sand. the rest of the page is a diagram of the rock cycle: sand is compressed down to rock strata, while magma rises, creating new rock

three panels. a green wave carrying an orange nautilus, half in the water, half fossilized. a closeup of rock strata with a small marine fossils. the river curving off the right side of the page

a single scene. the river cuts through the canyon while a fossilized leviathan spans the cliff. four panels on the right side of the page highlight oyster fossils on the canyon wall

three panels. the river exiting the canyon. a diagram depicting the river delta with text reading "fig 3.1 silt deposits". finally, the ocean floor, where fish swim through a living oyster bed