1898] THE ESKERS OF I HE LAND 245 



In some places on the low ground the esker sea drifts (as 

 Kinahan terms them) are spread out in undulating sheets, as in 

 the County of Kildare. The famous Curragh may he cited as a 

 tabular deposit of such materials. Now all these deposits point in 

 the clearest manner to ' the rushing of great waters ' ; and if we only 

 consider the thaw of such an ice-sheet, as all admit to have existed, 

 we can have perhaps Hoods and rushing waters enough for any pur- 

 pose, without calling in the aid of subsidence beneath present sea- 

 level. 



Mr Kinahan does not, however, forget that the formation of the 

 eskers is a disputed point ; but he thinks it probable that they are 

 modifications of the banks and shoals which accumulate at (1) the 

 colliding, and (2) the dividing of the flow-tide currents of the esker 

 sea, similar to those that are found in the seas around Great Britain 

 and Ireland at the present day. He examines three contem- 

 poraneous instances of the ' colliding ' of currents giving origin to 

 bank formations : 



(a) In the Irish Sea, in the viciuity of the Isle of Man, there is 

 a meeting of the north and south flow-tide waves, or a ' Head of 

 tide.' Where the tidal currents meet they neutralise, forming a 

 mass of currentless water that simply rises and falls, depositing silt 

 and other materials. 



(b) There is a ' Head of tide ' in the Straits of Dover ; and 

 (e) In the German Ocean, between Norfolk and Holland. 



But in the Straits of Dover and in the German Ocean the 

 meeting is not precisely a case of ' colliding,' as the currents pass 

 for some distance ; and at their edges, or their junctions, long banks 

 of gravel and shingle accumulate. 



It is also found, says Kinahan, that long banks of gravel and 

 shingle may form at the dividing and splitting up of the 

 flow-tide currents. We have here some resemblance between 

 currents at sea and rivers on land. Just as the river-flow, dividing 

 at the outlets, makes a deposit which may eventually become a delta, 

 so does the ocean-current where it parts produce an accumulation 

 varying in its constitution, extent and form with the nature and 

 supply of materials affected by the moving mass of waters. 



As an illustration Kinahan cites the following: From Greenore 

 Point (Co. Wexford) a main current runs northward up the Irish 

 Sea, while secondary currents break off into Wexford Bay; and at 

 the junction of these currents with the main one there are long 

 banks between Greenore Head and Wicklow Head. Similar 

 results, he adds, must have occurred in the esker sea. He applies 

 his theory in this way : 



The flow-tide wave entering at Galway must have sent a main 

 current eastward to the coast between Drogheda and Dublin. 



