41. Fossils from the shale have been invaluable for studying the rapid diversification of life's anatomical designs in the Cambrian period . 42. Its species lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period . 43. Coprolites have been recorded in deposits ranging in age from the Cambrian period to recent times and are found worldwide. 44. It is in diameter and is estimated to be less than 500 million years old ( Cambrian period or earlier ). 45. The various species lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period . 46. In the Cambrian period , however, there were few scavengers to disturb the creatures once they were grounded and buried, Hagadorn said. 47. Tests are known as fossils as far back as the Cambrian period , and many marine sediments are composed primarily of them. 48. Most shells of marine molluscs fossilize rather easily, and fossil mollusc shells date all the way back to the Cambrian period . 49. This was true during the Cambrian Period , but the same event also happened approximately 66 million years ago but not as severely. 50. A new Cambrian Period fossil bed was discovered more than a year ago in China, complementing a bed in Canada, Ross said.
