Crossword clues for the word: TRIASSIC The word TRIASSIC has appeared as an answer to at least 10 crossword clues on different crossword puzzles. Crossword clues for TRIASSIC Showing 1 to 10 of 10 results Clue(s) Arizona's Petrified Forest dates from this period Early dinosaur period First period of the Mesozoic Era Mesozoic period Period bookended by extinction events Period in which dinosaurs appeared Period of the first dinosaurs Period when dinosaurs appeared Period when mammals first appeared Post-Permian period