1 66 The Irish Naturalist. 



boulder clay, such as may be seen in the coast section, might 

 possibly give rise to the same effect. 



Near the road, within a stone's throw of Enniskerry, occurs 

 by far the finest section which is to be seen in the valley, and 

 of decidedly unusual character. Here the boulder clay, of 

 which only the upper surface is exposed, is seen underlying 

 about seventy feet of sands and gravels. The boulder clay 

 contains fragments of shells as usual ; it is succeeded by a 

 curious alternation of boulder clay and gravelly beds, so that 

 the lowest portion of the section is as follows : — 



Feet. Ins. 



Red-brown boulder clay, 



Laminated sand, . 



Limestone gravel, . 



Red-brown boulder clay, . 



Laminated sand, . 



Limestone gravel, . 



Top of thick deposit of boulder clay. 



In the intercalated clay shell-fragments occur, and in the 

 beds of gravel Astarte compressa was found, with fragments of 

 two other shells. Attention may be called to the regular 

 gradation from gravels through sands to boulder clay, and, as 

 thin beds of boulder clay rest quite undisturbed on evenly 

 laminated sands, it would be an obvious suggestion, were we 

 dealing with any other than glacial deposits, that the whole 

 were of aqueous origin. The section is continued upwards 

 into varying beds of sand, frequently micaceous, some finely 

 laminated, some false-bedded ; sandy and clayey gravels, and 

 pebble beds, composed of Carboniferous limestone and granite ; 

 the several beds varying in thickness from one inch to two 

 feet. The whole concludes above with a massive band of 

 brown sandy clay, full of rounded, sub-angular, and angular 

 pebbles and boulders chiefly of Carboniferous limestone, 

 irregularly scratched. This section contrasts strongly with 

 the other exposures of boulder gravels in the extreme clean- 

 ness of the sands and gravels, and the apparent total absence 

 of shell-fragments above the last bed of boulder clay, i.e., in 

 the greater portion of the deposit. 



(to be concluded.) 



