IN THE DEGRADATION OF THE LITHOSPHERE. 385 



siclered in connection with the islands which he out beyond the 

 shelves of the continents in those portions of the oceans which are 

 generally regarded as separate and distinct from continental struc- 

 ture. The connection of the repeating patterns and joints may be 

 demonstrated from the structures along the New England coast and 

 as it illustrates the principle referred to will be described in some 

 detail. The particular problem here may be stated as follows : to 

 show in the first place that the lines of distribution of the islands, 

 bays, harbors, reefs, and other land masses in the Gulf of Maine 

 are arranged in some definite structural relation with each other 

 and with the rock masses of the main land, and secondly to con- 

 nect this structure with processes of degradation above and below 

 sea level. If this can be done and certain lines of uniform control 

 shown to be present it is then proposed to apply the same line of 

 reasoning to oceanic islands which are now not so connected with 

 adjacent land masses as those islands in the Gulf of Maine are, 

 and try to show that lines of jointing have been in control of the 

 distribution of these islands; and lastly that lines of joint control 

 being a factor in the behavior of the lithosphere we have here a 

 general agent controlling the degradation, that is the lowering, of 

 the lithosphere surface irrespective of whether the other agents 

 present are variations of atmospheric or of hydrosphere contact. 

 Part of the demonstration of marine planation in connection 

 with the New England coast has been rendered unnecessary by 

 the publication of Barrell's paper just referred to ; this being pub- 

 lished after I had begun my own investigation. However, this 

 paper establishes the point which may be regarded as of very great 

 importance, and that is the demonstration of former widespread 

 plains of marine origin rather than simply plains due to atmos- 

 pheric means of erosion and degradation. In connection with these 

 New England plains may be mentioned also the terraces of the 

 Maryland Geological Survey^^ such as the Wicomico, Sunderland, 

 Talbot, etc., terraces which are undoubtedly of marine origin, 

 though not necessarily of joint control in any manner, but built on 

 older marine plain development. It is desirable, however, for the 

 sake of the argument to show some of the character of marine 



35 Maryland Geological Survey, Pliocene and Pleistocene, Baltimore, 1906. 



