11. This sea gradually retreated from the state before the end of the Paleozoic era . 12. The rocks in the watershed date to the Precambrian Era and Lower Paleozoic Era . 13. Orthocerids flourished in the Paleozoic Era , giving rise to such intriguing forms as the coleoids. 14. The municipality of Badajoz contains soils derived from tertiary deposits, dating to the Paleozoic era . 15. The first period of activity occurred during the Paleozoic era , with two periods of change. 16. Sauropsids evolved from basal amniotes stock approximately 320 million years ago in the Paleozoic Era . 17. It is composed of rocks from the Paleozoic era ( 250-500 million years old ). 18. Much of New York was covered in seawater during the early part of the Paleozoic era . 19. The Western Carpathians have a complicated geological structure, that has been formed since the Paleozoic era . 20. However, the swamps bearing these plants would dry up before the end of the Paleozoic era .
