Permian Period
Starting 289 million years ago and ending 252 million years ago, lasting 37 million years until the next period. This period has the famous land mass known as Pangaea the supercontinent, surrounded by the global ocean called Panthalassa. Since the rainforest of the previous period was gone what left in its place was vast desert at the continental interior, which led to the dominance of the reptile. The climate changed from still coming out of the ice age into warmer climates and cycled between cool and warm. The end of the period left a mass extinction of many marine animals, about 90% actually, probably due to the lack of food by the coast along with very low amounts shallow water coasts.