Last summer, I had the opportunity to visit Amazing Grace Ranch. It is located in Ness County, Kansas. It is ran by Tom and Kimberly Gdovin. The Niobrara Formation is extensively exposed on the Ranch, so there are lots of places and opportunities to find fossils. Tom and Kimberly are Christians who desire the fossils found on their property to be used for God’s glory, rather than used to teach the evolutionary narrative. Thus, they regularly open their ranch to creationists and creationist groups. Another member of the Board of Heart of America, Stan Bryant, has been to Amazing Grace Ranch several times to collect fossils. Last summer was my first time.
The Niobrara Formation is sometimes called the Niobrara Chalk. It is not made of true chalk, but it is composed of microscopic fossils composed of calcite, which makes it appearance and texture similar to chalk. The Niobrara Formation is one of the more famous and well known fossil bearing rock layers in Kansas. Most of the classic fossils from Kansas, such as mosasaurs, plesiosaurs, sharks, and Pteranodon, come from the Niobrara Formation. I want to share some photographs of what I found at the Amazing Grace Ranch.
The first thing I want to share is not a fossil at all. It is a large chunk of calcite crystals. In a couple of locations, there were seams of calcite crystals emerging out of the rock. I guess is that the calcite that is naturally found in the formation was dissolved in water and traveled along cracks in the rock. The calcite then precipitated in these cracks, creating the seams of calcite crystals.
The most common fossils found in the Niobrara Formation are bivalves shells: clam shells. I found two types: large inoceramid clams and smaller oyster shells. Both types of shells can be seen above. On the right is a fragment of an inoceramid. On the left is another fragment of an inoceramid but with oysters attached to it.
Here is another inoceramid with attached oyster shells. Between the oysters and sediment attached to the shell, you basically cannot see the inoceramid underneath. However, this specimen illustrates how large inoceramids can get. Some larger specimens can get to be two feet across!
Oyster shells are commonly found on inoceramid clams. Likely, the large clams had the oysters growing on them while they were still alive. Thus, the oysters are typically found on the outside surface of a clam shell. However, there are a couple of shell fragments I have seen where oysters are found on both the outside and inside surface of a clam shell. What likely happened is that the inoceramid had oysters growing on its outer surface, then it died. Somehow, the valve was flipped over, and then oysters began growing on the inner surface. If we consider the Niobrara formation to have been laid down during Noah’s Flood, that indicates that some fossils that we find are of creatures that died prior to the onset of the Flood.
After clams, the next most common type of fossil in the Niobrara Formation are fish. The image above shows several fish vertebra. Five of them can be seen in a row under the ruler. Two more are embedded in the rock. The two in the rock are articulated, meaning they are attached to each other as they would have been in life. Unfortunately, the type of fish cannot be determined from these few vertebra.
This fossil is distinct enough that I can make a tentative identification. It is a dentary, the upper jaw bone. You can see teeth protruding along the bottom edge. This jaw appears to belong to Cimolichthys. Cimolichthys can be compared to a pike or a barracuda in general shape. It probably was a predator like a pike and a barracuda, and could have reached lengths of six feet.
The last thing I want to share is not a fossil, but a transition. See the light colored rock in noticeable layers? That is the Niobrara Formation. See the looser, more jumbled sediment above that? That is sediment that accumulated recently. In other words, if the Niobrara Formation was truly laid down during the Flood, what we see in the above photograph is the transition from the Flood (Niobrara Formation) to post-Flood (the jumbled, loose sediment). Now, in other parts of Kansas, there is another Formation lying on type of the Niobrara. That other formation is called the Pierre Shale, and it was likely also laid down during the Flood. Either the Pierre Shale was never laid down here or the Pierre Shale used to be here but it was since eroded away. Whatever happened, the boundary visible in the photograph above represent the remaining boundary between Flood sediments and post-Flood sediments.
Thoughts from Steven
Heart of America Science Resource Center 