1871.] 119 LShaler. 



conclude that the uplift took place after the tertiary series of rocks 

 began to be laid down, and that the disturbance in the tertiary beds 

 at Hatteras and Martha's Vineyard occurred during the same period 

 of upheaval. It is not improbable also, that the whole of the disturb- 

 ances of the Richmond axis did not take place at the same time, but 

 at successive times, during two or more geological periods. 



CHANGES OF LEVEL OF THE HATTERAS COAST. 



There is a change in the character of the surface of the country, as 

 we pass southward from Petersburg. North of that point everything 

 seems to indicate that the topography is the product of many thou- 

 sand years of aerial erosion. As we go southward, the evidences of 

 the atmospheric action grow steadily less and less manifest. At Goulds- 

 boro' the streams seem to have had little to do with shaping the 

 surface of the country. Their basins have but a slight slope towards 

 the channel. But what topography there is seems to be entirely the 

 result of river action in its broadest sense. The slopes are all those 

 normal in river systems, though very slight. In the section from 

 Gouldsboro' to Newbern, we observe, however, some decided pecu- 

 liarities. Soon after passing the first-named place, on our way to the 

 coast, there is an apparent diminution of height, and a gradual 

 change of topography. The long, low ridges could not well have 

 been formed by subaerial erosion. They do not lie normally to the 

 course of the streams. I am satisfied that the topography is of sub- 

 marine origin, as is that of the South Carolina coast above the Sea 

 Islands. The long winrow-like ridges are, in shape, like those now 

 found along many of the shoal, tide swept sea floors of our coast. The 

 drainage seems to have found its way around these low reliefs when 

 the country became uplifted, without changing them much. Gener- 

 ally the streams find their way around and between the ridges, rarely 

 cutting them across. The behavior of the streams among these undu- 

 lations reminds one very much of the way in which the streams in the 

 Alleghany system cut their way across the series of ridges of that 

 mountain region. 



There is reason to believe that the subsidence of the land in this 

 region is still going on, and that since the last considerable uplift 

 there has been a sinking, amounting to several feet, at least. There 

 are a variety of facts tending to support this conclusion, which are well 

 established by the observations made since the settlement of the coun- 

 try. At Charleston, S. C, the phosphate bed which, at a point six 



