334! Bcientific Proceedings, Royal Dublin Society, 



XXX. — GLACIAL MORAINES ON MOUNT LEINSTEE, 

 COUNTIES WEXFORD AND CARLOW. By G. H. KINAHAN, 

 M.E.I.A., &c. Plates XXVII., XXYIII., and XXIX. 



(Read, June 19th, 1882.) 



In the coom at the head of Glen Clody, situated on the north- 

 east side of Mount Leinster, there are remarkable traces of a 

 glacier, to which I would direct the attention of the Society, 



These traces consist of two long lines or walls of heaped-up 

 granite blocks, which, from their character and the way in 

 which they run, can be accounted for only by their having been 

 deposited round the edges of a small glacier at two different 

 stages of its development, at each of which it must have had 

 very well-defined limits. The general appearance of the coom is 

 represented by the sketch, Plate XXVII., while Plate XXVIII. 

 shows the extent of the glacier at the two stages of its develop- 

 ment; as indicated by the two lines of blocks, the blue representing 

 the glacier at its last stage. 



The south-east face of the north-west part of the inner moraine, 

 Plate XXVIII. C, which is formed of huge blocks, is remarkably 

 grand; being straight, nearly perpendicular, and from 20 to 40 feet 

 high ; it is represented in Plate XXIX. 



The line of blocks outside the glacier, as represented in Plate 

 XXVIII., indicates its original and greater extent. 



The moraines in question are particularly interesting, for this 

 reason that they are so different from the general type of corry 

 moraines, of which there are so many in this country. They 

 are almost entirely composed of large blocks without small 

 detritus mingled with them ; whereas ordinary corry moraines, 

 though containing and carrying large blocks, have so much 

 small debris mixed with these that they can act as dams to the 

 tarns, or small lakes, which sometimes occupy the corry. I 

 believe that there has been a peculiarity in the mode of their 

 formation, apparently illustrated by what I have observed to 

 take place at the present day in the same district. 



As has been already pointed out in my " Geology of Ireland," 

 page 311, in some winters large snow-drifts are formed in the 

 cooms of the Lugnaquillia Mountains ; and when the surfaces of 

 these drifts become frozen over, all blocks that fall from the 



