Geological Society of Ireland for 1847. 315 



the unusual appearance of stalagtites and stalagmites discovered in the 

 Cave of Dunniore, county Kilkenny, he found, upon examination, that 

 they contained phosphoric acid, probably in combination with lime. 

 He referi'ed to the researches of M. Dumas respecting the extreme 

 solubility of phosphate of lime in water charged with carbonic acid, 

 so that bones or ivory-shavings immersed for a few hours in Seltzer 

 water are softened, and have many of their phosphates removed, 

 pointing out that the phosphates in this case must have been derived 

 from the dolomitic and limestone beds surmounting and including 

 the Cave of Dunmore. The late labours of chemists have shewn us 

 that the phosphates, so important for the growth of cereals, are far 

 more diffused through rocks than was at one time supposed, and this 

 discovery of phosphoric acid, even in the stalagtites and stalagmites 

 of a limestone cave, is another proof of this diffusion. 



In another communication to the Geological Society of Ii-eland, 

 Mr Mallet brought under its notice some views as to the circum- 

 stances under which the quartz rocks and slates of Wicklow have 

 been arranged, with some remarks upon a peculiarity of lamination 

 in the finer-grained and micaceous slates. His object was to shew 

 that the component deposits were all due to the sorting and trans- 

 porting power of water in motion, the cleaner-washed sand and pebbles 

 having formed the base of the present quartz rocks. He referred to 

 the different conditions under which deposits were now being effected 

 in the upper lake of Glendalough, in the county of Wicklow, as a good 

 illustration of the sorting and arrangement of deposits at different 

 depths. Regarding the ridges and furrows resulting from the fric- 

 tion of water upon loose sands, Mr Mallet points to their occurrence 

 in the lake beneath shallow waters, and while remarking upon the 

 supposed accumulation of certain Silurian deposits in deep water, 

 directs attention to the ripple-marks found so frequently among them, 

 observing that these must either be confined to shallow waters, or to 

 situations where streams of water moving with sufficient rapidity can 

 produce them. 



That the quartz rocks of the counties of Dublin, Wicklow, and 

 Wexford, are but clean sands or quartz pebbles, agglutinated by silica, 

 which, while in solution, probably often by the aid of an alkali, not 

 unfrequently dissolved the outer edges of the siliceous sands and 

 pebbles, appears very probable, indeed is now well understood, and 

 the quartz rocks in the districts above mentioned afford good illustra- 

 tions of this view. Eespecting the " ripple-marks," as they have been 

 commonly termed, — a bad name, inasmuch as they may readily be 

 produced at any depths where a current of water can move with suf- 

 ficient velocity, — we would direct the attention of observers to a 

 study of those really made by the to-and-fro motion of waves in shal- 

 low water, or where tides drain off extensive flats, and to those really 

 due to a constant friction of water in a given direction, in order duly 



