Whence the Shadows? 211 



Some 20 million years ago, a sea-the Temblor, paleontologists call 

 it— covered the area. Around what is now Sharktooth Hill the sea was 

 no more than 200 feet deep, and the thousands of fossils found there 

 today show that it teemed with marine life. There were whales, por- 

 poises, dolphins, sea cows, seals, and sea Uons. Aloft and on the surface, 

 where they were frequently snatched by predators, were seabirds not 

 unlike today's gannets, petrels, albatrosses, and geese. And prowling 

 about this rich hunting ground were giant sting rays weighing several 

 hundred pounds, and 25 or more species of sharks— including one 

 monstrous species as long as 120 feet or more. 



The length of this fantastic shark has been determined by its enor- 

 mous teeth. Some of the teeth found at Sharktooth Hill weigh 12 ounces 

 and are nearly 6 inches long; 3-inch and 4-inch teeth are common. They 

 are triangularly shaped, similar in shape to those found in today's Great 

 White sharks, which can exceed 30 feet but whose teeth are about an 

 inch and a half long at that size. 



Large, triangular fossil shark teeth like those from Sharktooth Hill 

 have been found in many geologic sites and in several present-day 

 coastal areas, such as Staten Island, New York; Venice, Florida; the 

 Calvert Cliffs on the western shore of Chesapeake Bay, and also in the 

 West Indies and New Zealand. 



The teeth belonged to an ancestor of the Great White, the Carchar- 

 odon, which abounded in Miocene seas. When fossil shark teeth were 

 first found and reported by naturalists in the seventeenth century, they 

 were classified as fossil birds' tongues or vipers' teeth. It was incon- 

 ceivable that they could have come from a shark, so non-existent beasts 

 were conjured up to fit the fossils. 



Even today, the immensity of the Carcharodon strains the imagina- 

 tion. The American Museum of Natural History has built a model of 

 the jaws of this monstrous shark, basing the size on actual teeth that 

 have been found. The jaws, large enough for a man to stand in with 

 arms outspread, would fit a shark at least 80 feet long. And this was 

 a medium-sized member of the species! Its teeth were not up to the 

 prodigious size of the biggest found at Sharktooth Hill, whose Carcharo- 

 do?i was a giant among giants. 



The Carcharodon is the largest fish of which man has yet found 

 evidence and, though it is apparently extinct, it seems not to be very 

 extinct. Early in this century, 4-inch Carcharodon teeth were dredged 

 from the bed of the Pacific Ocean. They seemed to be "fresh," rather 

 than fossilized. The fact that they were dredged up indicated that they 

 had been deposited recently. Older teeth would probably have been 

 covered by so much silt that the dredging gear of those days could not 

 have snagged them. 



