"Â “ In the 1960s the base of the Cambrian was determined to be 570 million years old , and this date appears on age compilations even in the late 1980s . Recently , however , there have been significant improvements in radiometric dating techniques . The Precambrian/Cambrian boundary is now dated at 543 million years old . The Â “ MiddleÂ ” Cambrian is dated at about 510 million years ago , whereas the oldest trilobites are no more than 522 million years old , which suggests that the bulk of Cambrian time was Â “ pre-trilobiteÂ ” Â ” . ( Rare Earth : Why Complex Life is Uncommon in the Universe , Peter D. Ward & amp ; Donald Brownlee , Copernicus/Springer-Verlag , 2000 , p130 Â– 131 )"
"2 ) Even if we accept the statement `` Nearly all animal phyla * made their first appearance [ about 543 - 525 million years ago ] `` ( note the * ... wonder what that material says ) , it still does n't address the appearance of the vast majority of species , or of higher taxa like genera and classes . Why are there no robins , eagles , vultures , chickens , emus , frogs , turtles , lizards , alligators , sharks , carp , perch , dolphins , whales , seals , foxes , rabbits , cats , dogs , deer , antelope , zebra , horses , kangaroos , elephants , bats , monkeys , chimps , humans , and so on in the Burgess Shale or other Cambrian strata ? Evolution has a perfectly reasonable , and supported , explanation . But if God created all animals on `` day x `` , then we should expect to find all types of animals - elephants & amp ; humans & amp ; mice , trilobites , and dinosaurs of all various sizes and mobilities , for example - all mixed in the same strata ... but we do n't . ( PS : And `` flood sorting `` does n't resolve this problem with the religious , Creationist position ) . 3 ) The Cambrian `` explosion `` was not really a sudden explosion , but more of a extended event . A recent article ( The Early Evolution of Animals , David J Bottjer , Scientific American , August 2005 ) describes a bilaterian - a bilaterally symmetrical animal - found in strata that is dated to between 580 million and 600 million years old . That 's roughly 45 to 50 million years prior to the beginning of the Cambrian explosion . And the author adds ..."
"In the 1960s the base of the Cambrian was determined to be 570 million years old , and this date appears on age compilations even in the late 1980s ."
"it still does n't address the appearance of the vast majority of species , or of higher taxa like genera and classes ."