551.33(41.5) 243 
Tit 
The Eskers of Iveland 
Part Il. 
HE various theories which have been advanced to account for 
eskers may, I think, be reduced to two classes— 
The first class will contain those held by geologists who, while 
differing in matters of detail, agree that the eskers result from 
marine agency—tides and currents. : 
The second class will contain those propounded by writers who 
see their way to dispense with marine action, and who find in the 
agency of glacier-ice the origin of all manner of drift deposits. 
The Neptunists—a term which will serve to indicate the 
upholders of the marine agency theory—are well represented by 
Jukes and Kinahan, who have the advantage, as regards the 
eskers, of minute practical acquaintance with the geology of 
Treland. 
The Glacialists are represented by Hummel and Geikie—the 
former belonging to the Geological Survey of Sweden, and the latter 
to the Geological Survey of Scotland. 
I begin with J. Beete Jukes, who was for many years, prior to 
his death in 1869, connected with the Geological Survey of Ireland. 
In his opinion the ‘ ridges’ “seem to have been formed by the piling 
action of two opposing currents, or to have been heaped up in the 
eddy at the margin of the currents running in different directions.” 
But it is in this ‘piling-up action’ that the difficulty lies. 
Irregular heaps or mounds of sand, gravel, or shingle may have 
been got together in this way, although it would not be so easy to 
account for the stratification observable in the true eskers, But 
when we come to consider the long narrow ridges of the railway 
embankment type the difficulty becomes really formidable. I have 
no doubt that Jukes is correct in saying that “many of the eskers 
were perhaps similar to harbour-bars in their mode of formation, 
and may be directly related in this way to the valleys running into 
the neighbouring hills, which must, of course, have formed bays or 
harbours during some part of the last slow rising of the land above 
the sea.” 
In Geikie’s edition of “ Jukes’ Manual ” of Geology, there is a note 
on p. 712, citing, as an excellent example of an old ‘ harbour-bar,’ 
