21. Northern and central Arkansas was a terrestrial environment during the Triassic . 22. Texas was home to a massive river system during the Triassic . 23. During the early Mesozoic, Triassic pelecypods were common Washington inhabitants. 24. They became extinct during the Permian Triassic extinction event } }. 25. But at the dawn of the Triassic , the worst was over. 26. The African and Eurasian plates during the Late Triassic and Early Jurassic. 27. It is a natural hill of Triassic sandstone capped by Keuper marl. 28. Gymnosperms show evidence for biotic pollination as early as the Triassic period. 29. The Rhynchocephalia originated by the Middle Triassic period and were distributed worldwide. 30. In the Late Triassic , ichthyosaurs attained the peak of their diversity.
