Small Shark Tooth
In Steno's day, fossils were regarded as strange tricks of the gods. Only eccentrics regarded them as the actual remains of creatures and this was frowned upon by church authorities. Some prominent naturalists had already voiced the suspicion that fossils known as tongue stones (glossopetrae) were shark's teeth. In 1667, Steno was able to study the teeth of a shark stranded near Florence, which convinced him ‘tongue stones’ were indeed fossil sharks' teeth. But what kind of sharks? More importantly, how did their teeth become imbedded in rocks? Since his fossil teeth were slightly different from the teeth of modern sharks, Steno suspected they came from a variety of extinct sharks. Steno wrote the founding book of Paleontology, called 'Introduction to a Dissertation on the Solid Substance actually Contained within Solids' and pointed out that it is only logical to believe that the top layers of rock must have been deposited after rock layers below. This is now known as the Principle of Superposition. Steno also pointed out that fossils in different layers could vary greatly. He planned to complete his work on fossils, but entered church ministry instead and served as Bishop of Munster in Westphalia (now Germany). He lived out the last years of his life in abject poverty and died in 1686, a forgotten voice until a century and a half later, when the creationist, Humboldt, rediscovered and promoted Steno’s work.
The teeth of the so called first fossil sharks - like Cladodus, from mid Devonian rocks - are surprisingly similar to modern sharks (Devonian rocks, which take their name from Devonshire, England.) Because of the sudden appearance of sharks in the fossil record, evolutionists have had real problems explaining their origin. Many have suggested that instead of being creatures which have evolved a non-bony (cartilage) skeleton, they originally had bony skeletons and later lost the ability to produce calcium deposits, so their skeleton degenerated to the cartilage only.
Despite the absence of any hard skeleton, a surprising number of whole fossil sharks have been found with fully preserved internal organs, such as kidneys, liver, heart, stomach, brain casing and intestines. Specimens are known from the USA (Cleveland shale in Brooklyn Heights, Ohio, Sarpy County, Nebraska, Cass County, Nebraska, Mason Creek area, Illinois, Logan Quarry Shale, Indiana, and Powell County, Kentucky), and from Holzmanden Germany, and Solnhofen Bavaria. Most of these sharks are found in shale supposedly deposited slowly in still water, but the evidence from the enclosed whole sharks tells us the shale was rapidly deposited. In Australia, fossil shark material is found in Central Queensland and Victoria (around Melbourne), and in South Australia (slightly east of Adelaide). In Western Australia there is an outcrop at Gin Gin, north of Perth. Shark fossils (teeth and bodies) are found worldwide. From the first to the last, the one thing you can be dogmatic about is that sharks have produced sharks, just as Genesis says God created them to do.
Sharks have a skeleton made of cartilage, (a soft material) so they have few hard parts to preserve. The most common shark fossils are teeth and occasional spines. The fossil teeth of one giant shark were 15 - 20 cm long (6-8 in). Known as Carcharodon, it reached 15 to 17m (45 -55 ft) in length and had a mouth approximately 2m (6 ft) across. It is still represented today by the well known savage Australian white shark. Fortunately it no longer grows as big. Shark teeth are generally triangular, arranged in several rows and are used for tearing not for biting. When the front row is worn down, the teeth bend forward and drop out. Their place is taken by the next row of teeth.