Head of the plain above the sea if 41 may be roughly estimated at from 20 to 25 feet. This thickness is sub- ject t constant change until grade level has become established. That recently the plain has stood at a higher level than now is shown by a terrace on its south side [Ill. 22;66 B] That its level is being lowered is shown by the trenches cut by the present stream. Lowering of level in the bed of the Wallibou is most noticeable in the 37 three two-mile stretch between the face of the Wallibou Estate bluff fronting the sea and a rockwall, an old lava constant flow from the Soufriere, where the drainage wooded from the northern slopes of Richmond Peak and the intermittent flow from bare the southern slopes of the Soufriere