I have been involved in an online discussion regarding whether or not the geologic column (Cambrian-Ordovician-Silurian-Devonian…) is real, or some sort of figment of geologists’ imaginations. Dr. Jay Wile, on his Proslogion blog, has written a post entitled Yet Another Failure of “Geological Column” Reasoning. Please note that I consider Dr. Wile (author of the Apologia series of home school science textbooks) to be one of the better young-Earth creationists; one who is willing to point out the scientific and theological shortfalls of the overall YEC movement when he sees them.
Dr. Wile argues that the discovery of fragments of grass phytolyths (tiny glass particles in grass leaves) in Cretaceous dinosaur dung (coprolites) is evidence that the whole concept of the geologic time scale is in trouble. After all, we had been told rather authoritatively that there were no grasses in the Cretaceous; that grasses did not appear until a few million years after the demise of the dinosaurs. He draws a parallel between this and another “failure” of the the geologic column: living fossils such as Coelacanths. If the geologic column is built on fossils, and if we discover that some fossils occur later or earlier than we realized, then perhaps the geologic column itself is suspect.
In the comments on Dr. Wile’s blog post, I have argued that the geologic column is more of an observation than an inference. I realize from philosophy of science that observations can be highly biased; that we often find just exactly what we are looking for. The young-Earth creationists claim that this is exactly what has happened; that geologists, imbibed with evolution, were expecting to find some sort of evolutionary order in the fossil record, and therefore they went out and found it. When one points out that the geologic column was largely deciphered before Darwin, they respond by saying that there was plenty of evolutionary thinking before Darwin (e.g. Lamarck), and that this is what influenced the early stratigraphers.
But is this what happened? Were the early 19th century geologists more influenced by evolutionary thinking, or by what they observed in sedimentary rocks?
In the early 1800s, William Smith compiled the first geologic maps of Great Britain. At first he focused on types of rocks, but he soon recognized that there were distinct fossil assemblages in the layers as well, and that these too could be traced across Britain .
Within the upcoming decades, scientists across Europe, and then in North America and elsewhere, began to make similar geological surveys. They discovered that not only were many fossils restricted to narrow bands of rock, but that there were many types that no longer could be found on Earth, and that there were consistent patterns in the order in which these fossils appeared in the geological record. This led to the construction (or discovery) of the geologic column. They eventually put labels on parts of the geologic column, such as Ordovician and Triassic.
Some of these early geologists were Christians, some were deists. Many were catastrophists, believing that the sedimentary rocks were the product of worldwide deluges, and many believed in the fixity of species. Few had the molecules-to-man picture that emerged after 1859.
That is a very brief summary of the development of the idea of the geologic (or stratigraphic) column, which is closely tied to the concept of geologic time. I want to make the case that the geologic column exists, that it is in need of an explanation, and that the standard geological explanation of deposition over millions of years works well, while that of the YEC Flood geologists falls far short.
The basic concept of the geologic column is that sedimentary rocks occur in the crust of the Earth in a specific sequence, and that this sequence has a global, rather than regional, basis.
Let’s start with the stratigraphic section that might be found at one location. This section would be a slice through the Earth. It might be exposed in a canyon or on a mountain side, or detailed by examining cores and cuttings as a well is extended deeper into the crust. My initial column (A) has five layers, which I will label 1, 2, 3, 4, and 5.
I am not all that concerned at this point whether those layers are sandstone, shale, or limestone. Instead, I wish to focus on the fossils. Layer 1 might contain marine fossils, such as trilobites and brachiopods. Layer 2 might also contain bryozoans and brachiopods, but of different genera than those found in layer 1. Layer 3 might contain corals. And so on for layers 4 and 5.
Now lets move down the road fifty miles and examine another section (B) of the sedimentary record.
Some of the layers clearly connect from A to B. This could be in terms of the rock types, the fossils, or both. But B has six layers, with B4 appearing between what was A3 and A4. Note that the correlation lines do not cross. This is not because of some evolutionary presupposition, but because the fossils in A1 match the fossils in B1, the fossils in A4 match the fossils in B5, and so forth.
Let’s move over one or two counties, and examine a third series of layers, section C.
We can see that A1 correlates with B1 and C1. B2, however has disappeared somewhere between B and C, and a new layer, C6, has appeared at the top of the section. Note again that there is no crossing of the lines.
For a final look, I’ll add two more sections, D and E.
It is apparent that some layers correlate all the way across from A to E, others pinch out, and still others appear. Once again, there is no crossing of lines.
These are all hypothetical columns of rock. In the real world, the same types of patterns occur, and geologists have given names to sets of rocks, based on the fossils that they contain. The lowermost layers contain distinct assemblages of fossils that have been given the label “Cambrian.” Higher in the column, another distinct assemblage of fossils has been named “Ordovician.” This continues upward for the entire geologic column.
Don’t get distracted by the numbers at this point. I am not defending so much the age of the Earth right now, but the reality of the geologic column, and I have this diagram here as an illustration.
The well-read young-Earth creationist, at this point, will say that this entire column does not exist in any one place; that it is all an inference. Look at the Grand Canyon, for example. It only contains fossil-bearing rocks from the Cambrian, and Devonian through Permian (no Silurian, Ordovician, or anything younger than the Permian).
That objection is pretty easy to answer. First of all, if one looks at the broader context, the Cambrian through Permian rocks of the Grand Canyon can be traced laterally to where they are beneath rocks in Utah that have Triassic, Jurassic, Cretaceous, and Tertiary fossils.
So in a distance of roughly one hundred miles, we can trace most of the periods of the geologic column. All that is missing is the Ordovician and Silurian. There are Quaternary deposits in this area, they just are not shown on the diagram. This sort of situation—correlation of layers—is the rule rather than the exception.
Second, there are a number of persistent sedimentary basins—areas that for one reason or another have continued to collect sedimentary deposits through much of geologic history—that do indeed contain layers from each of the geologic periods. If one drills into the Williston Basin (North Dakota, Montana, Saskatchewan), they will find the layers in the proper order. Starting from the bottom, there are layers from the Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Tertiary, and Quaternary. There is nothing out of order. This can be seen on the following stratigraphic correlation chart.
This really is a nice looking correlation chart; I encourage you to look at the full-scale version at the Core Lab web site. This chart (and others like it) show the same thing that I was doing with sections A-B-C-D-E earlier. Note that in the Montana and North Dakota columns at the far right of the chart, there are rocks from the Cambrian all the way up through the Quaternary. This chart only covers a corner of North America (British Columbia to Manitiba and down into parts of the United States). It could easily be extended to the whole of North America, and even to Europe and the rest of the world.
Note that the fossilized rocks express the same order no matter where you go. You simply do not find Cambrian rocks lying on top of Jurassic rocks. There is no crossing of the correlation lines. (Side note: YECs will often point to areas where older rocks are above younger rocks in areas that have been deformed by folding and faulting. If you undo the deformation, everything always slides back into place).
One can go to a number of basins throughout the world—in Libya, Bulgaria, China, Australia, Colombia, and elsewhere—and find exactly the same thing. It is not Cambrian-Ordovician-Silurian-Devonian in North America, and Permian-Cambrian-Devonian-Ordovician in Europe.
Many of the better young-Earth creationists acknowledge that there is some sort of order to the fossil record. They know that there are only invertebrates in the lower parts of the column, that land vertebrates (amphibians and then reptiles) don’t show up until the middle, and that mammals don’t show up until the top part.
At the simplest level, there was the proposal that marine organisms got buried first, and then the slow moving amphibians and reptiles, and the mammals and birds, who were quicker, were able to run faster (or fly) and so escape the earlier Flood waters. But this verges on being nonsense, as there are terrestrial sediments deposited throughout the column. And there are lake deposits, and shallow marine deposits, and deeper marine deposits also scattered throughout the column. And am I supposed to accept that all mice were able to outrun the advancing Flood, but pterodactyls couldn’t?
More sophisticated models have come along, such as various horizontal and vertical ecological zonation models. These models run into some of the same problems, as well as some additional ones. First is the problem of sorting. I would expect a worldwide Flood to at least sometimes have some turbulence, and to either mix groups of fossils together, or to put them out of order. Maybe even a little tiny bit. But it doesn’t seem to have happened. The order is Cambrian-Ordovician-Silurian-Devonian… It isn’t Cambrian-Ordovician-Mixture-Mixture-Mixture-Silurian, and it isn’t Cretaceous-Devonian-Permian-Cambrian. Ken Ham, the president of Answers in Genesis, likes to say, “If there really was a global Flood, you would expect to find billions of dead things buried in rock layers laid down by water all over the earth … which is exactly what you do find!” No, if the sedimentary rock record were a product of a single giant flood, I would expect to find a giant mess. I would not expect to find Cambrian-Ordovician-Silurian-Devonian…
A further problem with the ecological zonation models is that there would have had to have been plenty of critters still alive (and thriving) most of the way through the Flood. For example, think about all of the organisms of the Mesozoic Era (Triassic, Jurassic, Cretaceous). This includes not only the dinosaurs, but a host of mammals, birds, plants, and marine organisms, such as ammonites. Many of these organisms are unique to the Mesozoic, and even unique to subdivisions of the individual periods. Where were they all during the massive catastrophe that deposited the rocks of the Paleozoic? Vast areas of Mesozoic rocks are underlain by Paleozoic rocks. Were they huddled together on islands that had escaped earlier flooding? Were they floating around on mats of vegetation? Both of these proposals have very serious problems, but they are what the Flood geologists seem to be clinging to.
I’m barely getting started, and just scratching the surface. But I need to get back to Dr. Wile’s objection: that grass in the Cretaceous and Coelacanths in the Holocene are enough to discredit the whole thing. Do they? If anything, they discredit geologists and paleontologists who should have been a little more cautious in their statements.
The discovery of grass in dinosaur dung isn’t that big of a change. Paleobotanists had been saying that grass appeared sometime in the Paleocene or early Eocene (perhaps around 55 million years ago), and now we know that there was at least some grass around in the very late Cretaceous (a little over 65 million years ago). In any case, it appears that grasses were probably a minor constituent of the Mesozoic fauna. Perhaps I’m wrong on this. I don’t think any actual fossils of Cretaceous grass leaves have been found. In regards to the Coelacanth, which was once thought to have gone extinct in the Cretaceous but then discovered alive in the Indian Ocean, I think we should expect this sort of thing from time to time. There are fossils that, as far as we know, only lived in the Tithonian age of the Jurassic. Do we know everything? We should expect that for at least some of our index fossils (those fossils that are supposed to tell us the age of the rock in a very narrow range) that some survived somewhere and could even still be alive today.
These are little things. Grass appeared a bit earlier than we knew. Coelacanths survived throughout the Tertiary without leaving any fossils, but they are alive today. The plain and simple fact is that the geologic column exists. What the young-Earth creationists would need to find in order to overturn the well-established and well-justified concept of the geologic column is something like a mastodon in Devonian sediments, or an ostrich in the Ordovician. Until then, I’ll accept Cambrian-Ordovician-Silurian-Devonian… as an observation that is in need of an explanation.
Grace and Peace
|As an old-Earth creationist
I believe that the universe was created by the triune God of the Bible
I believe that the Bible does not dictate when this creation took place
I believe in a real Adam
in a real garden
in a real fall into sin
in real consequences for that sin
and in Jesus Christ as the only solution for sin