Despite all that we have learned about the fossil record and the evolution of life on earth, some people believe that the world was created, in more or less its present state, about 6,000 years ago. Dinosaurs such as Tyrannosaurus and Apatosaurus did not live millions and millions of years ago, the creationists say, but lived alongside humans in the days prior to a great global flood. The full weight of paleontological discovery crushes the vision of a recently created earth; the signature of the fossil record is unmistakable. Given the staunch refusal of creationists to accept this, many people have recently delighted in the discovery of a peculiar fossil in an Italian church.
The unexpected find was made late last month by paleontologist Andrea Tintori in the Cathedral of St. Ambrose in Vigevano. There, in a piece of marble-like limestone which composed part of the church's balustrade, Tintori saw what appeared to be a cross-section through an animal's skull. The slice was made through the skull from front-to-back, giving the viewer a top-down perspective on what was left of the fossil.
The shape in the stone is definitely a fossil, but what kind of animal it represents is another matter. According to a report issued by Discovery News, Tintori has provisionally proposed the fossil as a dinosaur skull: "The image looks like a CT scan, and clearly shows the cranium, the nasal cavities, and numerous teeth." Other news and pop-culture sites ate this up, and Gawker gasped, "An Italian paleontologist has discovered a fossilized dinosaur skull inside a small town cathedral. Yes, an actual dinosaur skull! In a church! How did it get there? Did Jesus kill it?!"
But I'm not convinced that the fossil is actually a dinosaur skull at all. Despite Tintori's assertion that there are preserved teeth, I do not see any, and there are symmetrical patterns on the fossil—such as a pair of indentations on the left side and a pair of small knobs on the right—that don't seem to correspond to a dinosaur cranium. Instead this fossil might be a cross-section through a very different kind of animal.
Even though the slab from the church looks like marble—a type of metamorphic rock that rarely contains fossils—there are varieties of limestone that resemble marble and preserve fossils inside. These rocks have often been used in architecture, and there are a number of places where you can find fossils embedded in marble-like stone walls or floors, including churches. Marine fossils are particularly prevalent in these slabs, especially coil-shelled cousins of living squid and nautilus called ammonites.
Given the age of the limestone in the Italian church (about 190 million years old), the numerous ammonite species which lived during that time, and the regular occurrence of ammonite fossils in marble-like limestone, I think there is a good chance that the "dinosaur skull" is actually a cross-section through the shell of one of the prehistoric cephalopods. Tintori has promised to carry out CT scans on the slab to find out for sure, so I guess we'll just have to wait and see.