Tethys Ocean from the east and the Pacific from the west. The rifting took place between North America and Africa, the rift produced multiple failed rifts, Mississippi River being the largest. The rift resulted in a new ocean, which today we call the Atlantic. | Tethys Ocean from the east and the Pacific from the west. The rifting took place between North America and Africa, the rift produced multiple failed rifts, Mississippi River being the largest. The rift resulted in a new ocean, which today we call the Atlantic. |