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XX.—'' BLACK SAND " IN THE DRIFT NORTH OF GREY- 

 STONES, CO. WICKLOW, BY GERRARD A. KIN AH AN. 



[Read, May 16th, 1881.] 



In November of last year (1880) I learned from Mr. James 

 Price, M, INST. C.E., that a quantity of magnetic iron sand had 

 been exposed on the beach north of Greystones, by the heavy 

 N.E. gales that had occurred during the previous month. 



When I visited the place, some time aftei^, I found that, for a 

 distance of several hundred yards along the top of the beach, 

 and just at the base of the cliff, there was a quantity of this black 

 sand ; it occurred in long patches several inches deep, in one case 

 over twelve inches ; but none of it was detected in the cliff, either 

 as a bed or vein. 



On a subsequent visit, after the thaw that followed the heavy 

 frost of January, I found that most of the places where the black 

 sand had been observed were covered by the debris that had 

 fallen from the cliff ; from some of the masses that remained 

 visible, a sample of about 7h lbs. weight was taken, and sub- 

 sequently washed. The beach on this occasion in several places 

 was quite black, owing to a thin layer of the sand, from which 

 another sample of sand was taken. This layer of black sand 

 appeared to be due to the wind (which was blowing strongly 

 from the north along the beach) blowing away the lighter sand, 

 and leaving the heavier materials behind. 



After the high tides, with N.E. gales, that occurred early in 

 March, I again visited the place, and found that though most of 

 the cliff debris above mentioned had been cleared away, yet that 

 none of the black sand, either on the beach or along the face of 

 the cliff, was to be found. 



Samples of the drift were taken from several places at different 

 heights along the cliff and panned ; in all very fine black sand, 

 but none of the coarser kind, was found ; some of the beds of 

 fine sand appeared to be richest in the black sand. 



In places through the gravel thin beds of a black material were 



