After the subsidence came another period of uplift, possibly still in progress.
Back of the islands are the quiet waters of lagoons, and at the mouths of rivers are several shallow bays indenting the mainland; these bays were formed by only a slight subsidence of the land and the rivers are filling them with deposits of silt.
There has been a land subsidence here, as throughout the N.
The autumnal subsidence of the river was followed by shallow ploughing performed by oxen yoked to clumsy wooden ploughs, the clods being afterwards levelled with wooden hoes by hand.
Some of the more viscous crude oils obtained in the United States are employed as lubricants under the name of " natural oils," either without any treatment or after clarification by subsidence and filtration through animal charcoal.