GEOLOGY. 19 



and eastern cliffs into dry land, having a sloping surface. A 

 period of repose then followed, during which, the ocean cur- 

 rents, acting on the land, wore it away, and produced along 

 the sea-margin an abrupt escarpment. Similar alternations 

 of periods of elevation and repose, in the same way produced 

 another and lower terrace and escarpment. After the second 

 period of repose, a third upheaval of the land produced a third 

 terrace, which now forms the low main land of the coast. 

 The other changes which have taken place also admit of a 

 satisfactory explanation. If, during the time when the present 

 sea-coast was slowly rising above the ocean, we suppose that 

 by the joint action of river sediment, sea-currents and waves, 

 a line of reefs was formed at a short distance from the shore, 

 and that they gradually arose to their present level, a chain of 

 low, sandy islands, separated from the main land by shallow 

 basins of salt water would be formed. The sedimentary mat- 

 ter brought down by rivers, would in time be deposited in the 

 quiet water between the islands and the main land, and form 

 a body of marsh. Whenever these marshes had become as 

 high as the usual flow of the tides, permanent channels for the 

 discharge of the water would be formed : and the distance to 

 which the salt water of the ocean would ascend in them, 

 would be established within fixed limits. Beyond the flow of 

 the sea water, trees and fresh water plants would then spring 

 up and extend down to the line of brackish water. If, after 

 the trees had been established, the land should sink, the salt 

 water being no longer confined to its usual channels, would 

 flow up to the sandy main land, and destroy the trees wher- 

 ever it reached. The dead trees would then decay down as 

 far as they were exposed to the action of the atmosphere. If 

 the subsidence of the land should now cease, or the accumu- 

 lation of sedimentary matter be greater than it, the stumps of 

 the former growth of trees would be buried in a new alluvium. 

 This new alluvium would gradually increase, until reaching 

 the height of the tides, new channels would again be formed, 

 and the line of salt water be driven back towards the ocean. 

 Whenever this occurred, another growth of trees would spring 

 up, and be gradually extended down the rivers. The present 

 appearances of the alluvial lands of the coast, indicate that 



