1913] JOHNSON—COASTAL SUBSIDENCE 465 
Island, there have been several recent changes in the number and 
position of the tidal inlets connecting with the sea, and the inhabit- 
ants date the death of certain of their trees to a new inlet opened 
some years ago. Along the New Jersey coast the general surface 
of the marsh slopes downward toward the land, and on the Delaware 
Bay section of this shore the waves are cutting rapidly into the 
marsh, which is unprotected by barrier beaches. As a result of 
the consequent shortening of the meandering tidal creeks, the tides 
rise progressively higher and higher toward the heads of the creeks; 
the salt marsh builds gradually up to the new level of high tide, 
-encroaching on the upland, killing the trees, and producing other 
evidence of progressive subsidence of the land. In the sea islands 
of South Carolina and Georgia we observed a number of more or 
less restricted localities where forests had been killed by a rise of 
high tide level following changes in size and position of tidal 
channels and bars, and one place where the death of the trees is 
dated from the cutting of a canal between two tidal channels. 
On the other hand, appearances of elevation of the land caused 
by a local lowering of the high tide level are not lacking. “Ele- 
vated” cliffs and benches of this origin were observed at a number 
of points on the coasts of Massachusetts, New Jersey, North 
Carolina, and Florida. 
3. Phenomena due to remote subsidence 
Frequent warnings have been uttered, most ably by SUESS, 
against the danger of confusing evidences of ancient changes of 
level with evidences of recent changes of level. Yet this error is 
found all too often in writings on this subject even today. ——— 
deeply buried in the salt marshes are correlated with the ae 
of cultivated fields by the tides; deeply buried salt peat 1s poi : 
with the dying of forests along the shore today; and on the ne 
of such correlations it is argued that we are in the presence a a 
great movement of subsidence which has continued ages >, 
‘throughout recent time. It has even been argued that the sap y : 
or drowned river valleys of the Atlantic coast are a conclusiv 
proof of recent subsidence. ee 
It is of the highest importance to recognize the possibility that 
atlar 
deeply submerged stumps and peat, embayed valleys, and sim 

