Terrestrial sedimentation was, indeed, a great feature of the Tertiary.
The natural process of sedimentation assisted the gradual artificial drainage of the marshes by means of embankments confining the river.
We have seen that in the Carboniferous rocks there are two phases of sedimentation, the one marine, the other continental; corresponding with these there are two distinct faunal facies.
Outside the region affected by glaciation, deposits by wind, rain, rivers, &c., have been building up the land, and sedimentation has N ~ been in progress in lakes and about coasts.
Gruber and Durham showed that sedimentation occurred when a small quantity of the homologous serum was added to an emul:_on of the bacterium in a small test-tube, and found that this obtained in all cases where Pfeiffer's lysogenic action could be demonstrated.
At the same time marine sedimentation was continued on the Pacific coast, but the faunas of the west coast and the interior bay are notably unlike, the latter being more like that of the coast north of the United States.
The relative value of any group of animals or plants for the correlation of distant areas must vary greatly with the varying conditions of sedimentation and with the precise definition of the zonal species and with many other factors.