74 Evolution and the Fossil Record
that they dried out repeatedly, but also delicate ferns and other plant fossils preserved intact,
which is hard to explain if they were created by energetic floodwaters.
One of the best lines of evidence is the distinctive white band that is visible just below
the rim on both sides of the Canyon, known as the Coconino Sandstone. This unit has huge
cross-beds (fig. 3.7E) that are only known to form in large-scale desert sand dunes, not under-
water. They also have small pits that are characteristic of the impacts of raindrops. How did
raindrops land on these surfaces if they were immersed in a great flood? Even stronger proof
is that many of the dune surfaces are covered with trackways of land reptiles (fig. 3.7F). How
does a creationist reconcile these dry sand dune features and dry land reptile trackways with
a huge flood event? I’ve read the creationists’ attempts to explain these features, and they
are classic examples of special pleading, twisting, and distorting scientific evidence as they
thrash around in their completely unconvincing scenarios.
And the most impossible thing the creationists ask you to believe is this: the entire
pile of sediments of the Grand Canyon sequence, soft, soupy, and supposedly depos-
ited during a single flood event, was then eroded down to form the present-day Grand
Canyon by the recession of the floodwaters. Wait a minute—didn’t the creationists just
use the recession of the floodwaters and the settling out of still water to deposit the thick
piles of postflood shales, sandstones, and limestones in the first place? Or if that’s not their
scenario, then how did a soft pile of wet mud, sand, and lime hold up without slumping
down and sliding into the gorge as the torrential retreating floodwaters rushed through?
Did the supernatural flood also suspend the laws of gravity, too? Anyone with common
sense can watch the Grand Canyon as it erodes today, with the long-hardened sediments
(now sedimentary rocks) slowly weathering and eroding, dropping into the canyon by the
action of gravity or by rains and small local canyon floods, and then slowly carried away
by the Colorado River.
Even more revealing is the fact that if you trace the rock units of the Grand Canyon
across distance, they change facies (gradually transform and intergrade sideways from
one rock type to another). For example, in the Grand Canyon, the Pennsylvanian period
(323–290 million years ago) is represented by the brick-red ledges and slopes of the Supai
Group, which is composed of mudstones and sandstones deposited in broad rivers and
plains. But, if you travel just 80 miles (130 km) to the west to the Arrow Canyon Range, just
east of Las Vegas, Nevada, the same interval (between the Mississippian limestones below,
and the Permian Coconino-Toroweap-Kaibab Formations above) is represented by a marine
Bird Spring Limestone, full of the shells of foraminifera and brachiopods. About 300 miles
(480 km) to the northwest, that same interval is represented by boulder conglomerate and
sandstones shed from an ancient mountain range of the Antler orogeny that eroded away
long ago and no longer exists. The fossils, and their position between nearly identical Mis-
sissippian limestones and Permian rocks, show that these Pennsylvanian rocks in Arizona
and Nevada are all correlative and roughly the same age. Yet they look entirely different.
These things are completely inexplicable if these rocks were all deposited as a worldwide
uniformly consistent layer cake by a single Noah’s flood.
Or let’s follow the Permian rocks (Hermit Shale, Coconino Sandstone, and Toroweap
and Kaibab Limestones) to the east of the Grand Canyon (fig. 3.8). By the time we get as far
as Monument Valley, these units have all changed facies. The Toroweap and Kaibab Lime-
stones have become thinner and thinner until they vanish completely near the Utah border.
In their place is a thick sandstone (much thicker than the Coconino) known as the Cedar