Below us dark, gullied ridges held another half million years of sediments. Beyond them was the basalt, laid down when this vast plain was swamped in lava, 5.2 million years ago.
In the process of extraction, according to the chief feature that the volcanic cones are situated in lava platform, the study area is classified as plain and mountain firstly.
在提取过程中，根据研究区内火山口均位于熔岩台地上的特点：首先，将研究区划分为平原和山地等地貌类型；
3
The colonists were desirous of reaching the plain upon which the superior cone of Mount Franklin had fallen, but the lava arrested their progress.