171 NATURAL SCIENCE [September 



Passing, for a little while, from this direct conflict of opinion, 

 we come to discuss the particular subject now before us. For the 

 present we accompany Jukes : " One of the most remarkable features 

 of the upper gravelly and sandy drifts is the way in which these 

 deposits are often heaped into mounds and ridges, which sometimes 

 run continuously over the surface of the country. Such ridges are 

 known as kames in Scotland, eskers in Ireland, and asar in Sweden. 

 These remarkable outlines are not due to mere denudation, but, as 

 shown by the external structure of the mounds, have usually been 

 produced at the same time as the mass of the sand and gravel was 

 deposited. 



' ; These mounds, in most cases, probably received their form 

 during their first accumulation ; but sometimes the surface of the 

 drift seems to be one caused by subsequent erosion." " In one con- 

 spicuous instance (Jukes adds), two or three miles north of Parsons- 

 town, which I visited in November 1861, in company with Mr A. B. 

 Wynne, a widely spread expanse of deep horizontally stratified lime- 

 stone gravel appears to have been so far acted upon by subsequent 

 denudation as to have now an abruptly-undulating surface consisting 

 of small mounds, ridges, and valleys running in various directions 

 over a space several miles in length and one or two in breadth. 

 One of these ridges, however, and the most conspicuous of them, 

 forms a long esker, or narrow gently-undulating bank some fifty feet 

 above the surrounding flat country, and some miles in length. Such 

 eskers are very numerous in Ireland over all the low central plain. 

 One is to be seen three or four miles to the west of Dublin, running 

 from the banks of the Dodder, past the old castle of Tymon, by the 

 Green Hills, towards the valley of the Liffey." Jukes mentions 

 similar accumulations at Maryborough, Stradbally, Borrisokane, and 

 other places. 



One of the most remarkable groups (although not mentioned in 

 particular by either Jukes or Kinahan) is situated at the western ter- 

 minus of the series, just three miles to the south-east of Athenry, at 

 St Joseph's College — locally known as ' Esker College ' — formerly a 

 Dominican priory, and so marked on the Ordnance Survey map, 

 but lately converted into a diocesan college. The locality is called 

 'Esker,' just as — to the great perplexity of post-office officials — 

 several other townlands to the west of the Shannon are so named 

 owing to the prevalence of the drift ridges. But ' Esker, Athenry,' 

 is distinguished among them all, no less by its history than by the 

 gigantic character of its ridges and mounds of limestone gravel, a 

 subject which I shall have occasion to discuss in some detail 

 further on. 



I quote again from Jukes : " The eskers are often opened for 

 gravel pits, as may be seen in the Green Hills, near Dublin, and 



