Bornean everglades

The rock was now Pennsylvanian-massive river sandstones of Pennsylvanian time. Flat, deck-like, it was comparatively undisturbed. It had been shed, to be sure, from eastern mountains, but had not been much affected by their compressive drive. Crazed streams had disassembled the plateau, leaving half-eaten wedding cakes, failed pyramids, oddly polygonal hair-covered hills. Pittsburgh was built […]

American conodonts

They happened to be within a third of a mile of warm-water American conodonts in rock of about the same age which had moved hardly at all. The Scandinavian conodonts had apparently come to Pennsylvania with the closing of the protoAtlantic ocean and been dropped ashore off the leading edge of the arriving plate. “Even […]


She said, ”I’d hate to tell you how many months I’ve spent here measuring every foot of rock.” Among the quartzites were occasional bands not only of sandstone but of shale. The shales were muds that had settled in a matter of days or hours and had filled in the lovely periodicity of the underlying […]

Under a microscope

She can now have a look at them under a microscope, seeing “bizarre shapes that any idiot can recognize,” and assign them variously to the Anisian, Ladinian, Cayugan, Osagean, Llandoverian, Ashgillian, or any other among tens of dozens of subdivisions of Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, and Triassic time. While recording ages, she […]

Modern episodes

One of the oddities of the modern episodes of glaciation is that while threefifths of all the ice in the world covered North America and extended south of Springfield, Illinois, the valley of the Yukon River in and near Alaska was never glaciated, and as a result the gold in the Yukon drainage-the gold of […]

Under the volcanoes

Under the volcanoes, the melted crust cooled in huge volumes as new granite batholiths. Basin-range faulting has elevated the batholiths to fourteen thousand feet, and weather has sketched them out as the Sierra Nevada. When seafloor goes into a trench, there can be a certain untidiness as segments are shaved off the top. They end […]

Metal discoveries

As you know, the hot water, circulating deep, picks up whatever is there-gold, silver, molybdenum, mercury, tin, uranium-and brings it up and precipitates it out near the surface. A vein of ore is the filling of a fissure. A map of former hot springs is remarkably close to a map of metal discoveries. Old hot […]

The Old Red Sandstone

The Old Red Sandstone was put down by rivers flowing southward to a sea where marine strata were accumulating in the region that is now called Devon. The size, speed, and direction of the riverstheir islands, pitches, and bends-are not just inferable but can almost be seen, in structures in the Old Red Sandstone: gravel […]

Great Salt Lake

When a geologist finds oolites embedded in rock-in, say, some Cambrian \outcrop in the Lehigh Valley-the Bahamas come to mind, and the Great Salt Lake, and, by inference, a shallow, lime-rich Cambrian sea. Our sample bag was like a ten-pound sack of sugar. I rolled over on my back, set it on my stomach, and, […]

The Avalonian Orogeny

The swelling up of mountains was described as an orogeny. Ontogeny, phylogeny, orogeny-accent syllable two. The Antler Orogeny, the Avalonian Orogeny, the Taconic, Acadian, Alleghenian orogenies. The Laramide Orogeny. The center of the United States had had a dull geologic history-nothing much being accumulated, nothing much being eroded away. It was just sitting there conservatively. […]