272 T. C. CHAM BERLIN 



A growth of the continental sheh" seaward to the extent of i ,000 

 miles would increase the sum of the thicknesses of the topset or sea- 

 shelf strata to the amount of 4,000 feet, if the shelf slope were con- 

 stant at I in 1 ,320; while the sum of the foreset beds on the abysmal 

 slope would increase to 176,000 feet, if its inclination remained 

 constant at i in 30, i.e., constant at a slope of about 2°. The thick- 

 nesses of topset beds under the range of slope given above would 

 vary from 3,000 feet to 12,000 feet and of foreset beds from 176,000 

 feet to 440,000 feet. In all this, it is assumed that there is abso- 

 lutely no subsidence of the crust, nor creep, nor diastrophism of any 

 kind, nor any change of any kind, except what may be involved in 

 keeping up a supply of terriginous matter and in maintaining normal 



Fig. I. — aa, sea level; bb, limit in depth of effective surface action; crust sta- 

 tionary; creep absent; silt supply constant; action strictly normal; slopes exaggerated. 



sea action on the shelf, and so maintaining a systematic growth 

 seaward. 



From this it is easy to see that, given a sufficient supply of 

 material and a continuance of normal action and static condition, 

 it would be possible for normal processes to build out into the ocean 

 a series of foreset beds that would sum up a thickness much exceed- 

 ing the whole geological column, without the slightest subsidence. 

 Even the sea-shelf beds in such a case would attain a very impres- 

 sive sum of thicknesses. 



In these statements, it is assumed that thicknesses are measured 

 in the standard way, bed by bed, at right angles to the bedding 

 planes. 



Under the perfectly stable conditions named, and on the assump- 

 tion that the angle between the topset and foreset beds of the con- 

 tinental shelf was maintained at 100 fathoms below the sea surface, 

 the series of shelf-sea deposits would never have a vertical depth of 



