MARYLAND GEOLOGICAL SURVEY 119 



in development and not continuous, and after a large number of obser- 

 vations had been compared throughout the Coastal Plain, it was found 

 that the great continuous terrace surfaces were those which have been 

 now designated as the Lafayette, Sunderland, Wicomico, and Talbot for- 

 mations. The minor terraces seem to be due to pauses in uplift and to 

 the swing of the stream as it cut first on one bank and then on another. 



There are beside these abrupt rises low, gentle elevations which stand 

 above the general level of the plain. These may be due to a number of 

 causes. They may indicate bars and spits, but certain of them doubtless 

 represent outliers of the next older terrace which were not quite reduced 

 to the general level of the surface when the water retired from that 

 region. There are all gradations of these, from outliers which evidently 

 had been reduced to about the level of the water to others which were so 

 far eroded as to leave nothing but a gentle swale in the topography. 



The depressions are usually gentle and may be described as saucer- 

 shaped. Many of them are undrained and are probably due to local set- 

 tling since the deposition of the formation, or to unequal deposition of 

 materials during its formation. 



The question may have arisen in the minds of some as to whether an- 

 other explanation may not be suggested by the facts here described. May 

 not these terraces have been cut by a river system on a stationary or a 

 gently rising land surface and may not the plain which is ascribed to 

 river, estuarine, and marine conditions have actually been formed as a 

 flood plain of the river system? The question is a fair one and has re- 

 ceived no little consideration from the author during the prosecution of 

 his investigations. There are, however, three conditions opposed to this 

 conclusion which may with propriety be given in this place : First, the 

 lack of an opposing bank to such a river system. As to the origin of the 

 Lafayette surface, there seems to be but one opinion, namely, that it was 

 deposited under marine or estuarine conditions. If the Sunderland is 

 taken to represent a terrace deposited by a river beneath the Lafayette, 

 where is the opposing bank to such a river system? The Lafayette and 

 Sunderland formations are absent on the Eastern Shore. This explana- 

 tion, therefore, will not apply to the two oldest terraces. Will it explain 



