98 Pioci'.iuiiiifjs of the Roi/al Irish Acitdeuij/. 



the pass at Gowlaiieinto thelieaitwatersof tlieCleady Eivev. Tliey are absent 

 along tlie noiili-easteni slopes of tlie Finnihy Valley because, when once 

 the ice withdiew from Strikeen, it ailniilled the lake to the headwaters of 

 the Finniliy, and the gravel brought east by the marginal drainage was 

 cheeked at this point, and built up the terraces at Letter. 



From the above considerations and a multitude of other details wliieh it 

 is impossible to discuss here, it will be seen the shore embankments of Lake 

 Kenmare are really part of the marginal deposits of the ice-sheet re-arranged 

 b}' the lateral di-ainage, ami brought to rest at the level of the lake. 



Uf treat Sta/fea in the Kcumarc Valley. 



A careful examination of the valley of the Koughty Uiver, between 

 Kenmare and Kilgarvan, i-eveals the fact that it is crossed by a series of belts 

 of moundy sand and gravel, sometimes associated with massive shore embank- 

 ments. These together form l>roken l>arrieis across the valley beneath the 

 level of the shores of Lake Kenmare. They occur at faiily regular intervals 

 of about a mile or a little more. Only four or five are really well defined, 

 and stand out aa striking objects ; but by fitting in the evidence in the lateral 

 valleys with that in the main valley, it is possible to distinguish as many as 

 nine in the nine-mile stretch of valley lielween Morley's Dridge and Kenmare. 



When followed above the shores of the glacial lake these gravel barriers 

 are found t^i pass into normal clay moraines, so that it is clear that in the 

 liottom of the valley they are really water-sorted moraines. Moreover, above 

 the shore-lines of the lake another interesting fact becomes apparent. The 

 morainic barriere are compf>sit«, consisting either of a group of smaller 

 moraines, or of one large moraine with a terraced face. There is thus a 

 double periodicity in moraine formation during the retreat, the larger stages 

 of moraine fonnation, with inter-spaces of alxjut a mile, Ijeing punctuated by 

 .tmaller stages with intervals of, perhaps, 50 or 100 yards. It is not possible 

 to determine how many of the minor moraines correspond to one of the 

 major stages, but the .«ub-division is very obvious. It is most clearly visible 

 on the slopes soiith of Mangertonbeg, on ihe north side of the valley, and on 

 the upland between Letter and Slaheny on the south side. 



Time-values of the Major and Minor Period icUie^i. 



The idea at once suggests itself that the minor oscillations thus recorded 

 are yearly, and that the larger stages represent a climatic oscillation 

 exicndiiig over a number of years. Confirmatory evidence to this eflect 

 is aflordetl by a small hut well-defined esker ridge on the shore to the south 



