STETSON 



59 



and shape of the bars are thought to vary considerably in a short distance horizontally. The 

 boat's course off shore is maintained by permanent range markers set up on the beach, dunes, 

 or cliff. Occasional echo sounding profiles have been run into deeper water from the outer ends 

 of the traverses with one of the Oceanographic's smaller power boats to supplement the above 

 data. It is not expected that any changes in bottom topography will be recorded in water deeper 

 than is found over the outer ends of the traverses, which is about 40 to 50 feet. Bottom samples 

 are also taken on the emerged and submerged portions of each beach not only to get an over-all 

 picture of the texture but also to determine, if possible, the relationship of texture to slope and 

 to other changes in the topography. 



As was expected to be the case, summer conditions were very stable. The easterly 

 storms of that season were neither heavy enough nor of long enough duration to produce sig- 

 nificant changes in profile. In fact, it seems probable that the profile of early summer can be 

 counted upon to last with very little change at least until the heavy gales of late fall and early 

 winter begin. 



The profiles figured here were chosen as examples of the type of surveys made and on 

 which some change has been observed, rather than as illustrative of any fundamental trends. 

 A delineation of the cyclical change which these beaches go through, if it is a cycle, can be 

 made only after the twelve months of observations have been carried out. It is expected that 

 these beaches will return to the profile observed during the summer months after having gone 

 through many variations; but this has never been established for any beach regime (Figs. 3, 4, 

 5, & 6), 



Figure 3. Highland traverse showing cut and fill on the emerged and submerged por- 

 tions. Note cutting of berms for the dotted traverse but no significant trends in the 

 offshore portion. Race Point Traverse shows smoothing of berms and also a very 

 marked excavation and seaward fill of the offshore section. 



Figure 4. Nauset traverse showing removal of an offshore bar. 



