1898] THE ESKERS OF I It E LAX I > 249 



college (which enclose on two sides the lawn or playground), and a 

 series of immense mounds or hills to the south-east, east, and north- 

 east. These sand-hills form a miniature mountain system with 

 valleys, and some curious bowl-shaped depressions. Seen at a little 

 distance, in the twilight they may easily be mistaken for a veritable 

 mountain-chain with sierra-like crest. But there is no appearance 

 of rock, the whole consisting of drift deposits, mainly limestone 

 gravel and sands, with a surface which in a ' dropping ' (i.e. rainy) 

 season supports a fairly good sheep pasture, and forms burrowing 

 ground for myriads of rabbits. Apart from these ridges and sand- 

 hills the country around is flat, and less than a century ago must have 

 been almost entirely covered with deep bog, but most of this has been 

 cut away. There are some outliers, and one long ridge, partly 

 levelled and obliterated, may be traced along the Kingsland road as 

 far as the outskirts of the town of Athenry, at one time the Anglo- 

 Norman capital of the province of Connaught. 



Having spent a number of years in this peculiar locality, 1 have 

 often considered how by any known agency of tide or current these 

 ridges and sand-hills could be shaped as they are. While some 

 features could be accounted for by marine action, others could not 

 be brought within range. How could the ' flow-tide ' heap up two 

 great parallel ridges within a stone's cast of each other ? If it is 

 within the function of the tides to accomplish this, I am afraid 

 we don't quite understand the question of ways and means. By 

 Hummel's theory we get over the difficulty. There is remarkable 

 parallelism among the asar of the Lake Malar district. And if 

 there were no such difficulty in the way of the marine theory, there 

 is a rather formidable one as regards the heaping up of a ridge so 

 high and steep -sided in proportion to width at top. 



The eastern end of the more northern ridge has been cut away 

 to make room for some of the buildings, and in this way is made a 

 very good section, which, although partly obscured by a wall and by 

 detritus at the base, affords the best view of the internal structure 

 of an esker that I have anywhere seen. This section shows a curious 

 alternation of sand and gravel beds with an occasional ' leaf ' of clay, 

 or rather lime-clay paste, but the dip is not quite so steep as the 

 sides. Owing to the percolation of rain-water, there is matrix of 

 calcareous matter which serves to bind the whole into a tolerably 

 compact mass, which, however, readily yields to the pick-axe, and 

 the loosened materials when screened, serve to mix with mortar for 

 building, Over the sides and top there is, however, a deposit of 

 aerial drift, in which the rabbits can work their way. Formerly, 

 the peat closely surrounded both ridges. I have heard it stated 

 that there is peat underneath the gravel. But 1 know that in the 

 summer of 1897 a pump was sunk within two yards of the section 



