G. H. Kinahan — Asar, Esker, or Kaims. 87 



margining the ice-sheet at its different periods of retreat, they 

 scarcely could be so regular in character or on such similar levels over 

 the whole island ; besides, the stratification of the materials com- 

 posing them ought always to dip in one direction, or be irregularly 

 jumbled together. In some fringe- eskers, as pointed out in one 

 of the papers previously referred to, the dip may in places be 

 only to one side, but the reasons for this peculiarity are explained. 

 If the sea, however, on account of the advance of the ice-sheet, bad 

 risen, all bars, fringes, and shoals due to it would be formed on 

 the same or nearly similar levels, which, during the great "Esker-sea 

 period," would be at heights lower than 350 feet ; while to a sea 

 of a lesser area and at a relative lower level would be due the esker 

 ridges in the low level valleys, such as the esker across the valley 

 of Lough Corrib, Co. Gal way. 



Although it seems to me that the great systems of eskers in Ireland 

 are due to the meeting of currents in a tidal sea, [such a, theory 

 having been promulgated about ten years ago, and since confirmed by 

 the observations of myself and colleagues], yet I am far from imagin- 

 ing that all eskers are due to marine currents, as some eskers are 

 asolian, that is, principally formed by the wind ; eskers of this class 

 from half a mile to seven or eight miles in length being not un- 

 common in places on the east and south-east coast of Ireland, while 

 inland in a few places are ridges of fine sand that probably had a 

 similar origin. Furthermore, there are eskers evidently formed by 

 the combined action of the waters of rivers and lakes assisted by 

 wind, while in some of the Irish hills, and even on ridges, are 

 eskers far higher than the limits of the " Esker sea," evidently due 

 to some kind of waterwork, and not to wind action. Such eskers, 

 indeed, might possibly be the remains of the sea work when its 

 level was much higher than at present ; this, however, appears 

 very questionable, as the traces of such a sea-level ought to be more 

 prevalent than they are, while as a rule in Ireland above the 350 

 feet contour-line the prevailing drifts are glacial or glacialoid. It 

 seems, therefore, more natural to suppose, that while the great 

 system of the Irish eskers was formed by marine action, small local 

 systems or single eskers may be due to glaciers or some other 

 cause. But I should not be surprised, if hereafter, when the Kaims 

 of Scotland and the Asar of Scandinavia are worked out in their 

 entirety, that the main systems are found to be of marine origin. 

 Before concluding I should mention that from the true Eskers or 

 Asar drift should be excluded the esker-like mounds or drumlins of 

 Boulder-clay and Moraine drifts, that have by many eminent writers 

 been confounded with the true Esker-drift, as has been pointed 

 out by the Bev. M. H. Close in his paper on the General Glaciation 

 of Ireland. 



1 General Glaciation of Ireland, Journ. Eoy. Geol. Soc. Ireland, vol. 1. part iii. 



