^Vl^l(iHT — Minor I'criudicitij in Glucial Ucircat. 



'M 



of lliu Gi'L-al iSciutliein Hotel, Kemiian.'. Do Gccr' liaa sliowii tliat eacli of 

 Llie iiuUvidual liillocks or gravel ceiilies, of wliicii tiic eskeis wtiidied hy liini 

 in Sweden are composed, is equivalent to two of the seasonal laminae in tlie 

 laminated clays in that coiiutiy, and so represents in general a year's retreat. 

 The esker south of Kenmarc is about 600 yards long, and contains seven or 

 eight of these hillocks. Tlie rate of retreat thus indicated is about 80 yards 

 per annum. The larger interval marked by tlie transverse gravel and 

 moraine belts, between whicli the esker is situated, can imly be roughly 

 estimated as from 1^ to If miles in length. This gives approximately an 

 upper limit of forty and a lower limit of twenty years for the length of the 

 period represented by the gravel barriers and the intervening intervals. The 

 mean of tiiirty years is comparable with the average length of the climatic 



Estuanne Mud-EMS Alluvium -M otecialGravelJ I Rock.^ 

 Esker Ridges > Mi)uncis.^=^fe:g) Succ«sslvelc« Fronts ._ 



l''iG. 2. — Sketch Miip of tlie Ksker Bulge, to the south iif 

 Keiimme, showing the sulidivisioii into annual 

 mounds. Tlie lidge is double throughout the 

 greater part of iis leugtli, ou aueount of the 

 subglacial stream having dischaiged by two 

 orifices at the ghicier front. 



periods established by Briickner- witliin which a dry and warm epoch is 

 succeeded by an epoch of lower temperature and greater precipitation. In 

 dealing with the interpretation of this esker as affording an indication of 

 time-values, it is clearly of importance to take into account its position 

 relative to the preceding and succeeding }ieriods of moraine formation. 'J'he 

 first point to be noted iii this connexion is that moraine formation at this 

 stage of the retreat is very ill-defined. The preceding period is weak, and 

 the succeeding period almost untraceable, and clearly the last of the series. 

 The rate of retreat was, therefore, probably becoming equalized as between 



■ Gerard tie Oeer : " A Tlionii(igra|iliiciil liecovcl of the Lnte QuHteriiiiiy Clinmle" 

 ill Die VciiiinhriiHyen lies Kiimas, Geol. Congress, Slockholni. ]!)](); "A (jeoiliroiiolo'^y 

 of theliisl 12. (K)() years," Geol. t'oiigress, Coiii|ito Reiuhi. mio, 



-Ed. Briiokuer : Ivliiu isoluvMiikimgou, [>. 2.'>2. 



