196 



Proceediugs of the Roi/al Irish Academy. 



passing across the old storm-beach, through two of the JN'eolithic sites, 

 and back to high-water mark. This section, omitting the portion 

 which ran from the one JN'eolithic site to the other over the summit 

 of a 90-foot sand-dune, is shown, fig. 12. The results show : — 



( 1 ) Crest of old storm-beach 6 feet above present high water. 



(2) The Neolithic sites lie well behind this line. The levels of 



the black layer at two sites, A and measure respectively 

 11 feet and 15 feet 8 inches. 



At site A, deducting 5 feet for storm -level and 4 feet for blown 

 sand at present exposed below the old surface, we find the old 

 JN'eolithic or pre-Xeolithic surface on which the blown sand accumu- 

 lated to be not more than 2 feet above present storm-level of high 

 water. 



ICO 75 S" r, ino ?00 30» 400 FEET 



Fig. 12.— Horizontal Sections of the Portstewart Sand-dunes. 



The same process applied at site B reduced the old surface to , 

 o feet 8 inches above present storm high water thus : — I 



ft. in. 



Level of black layer, . . . . ..158 above H.W. 



Less blown sand observed below black layer, 7 



Less storm level, . . . . ..50 I 



3 8 



