efra-hvolshellar caves at katla geopark, hvolsvöllur, south iceland

are breccia called can caves coarse collectively combination crossbedded deposits dug efrahvol efrahvolshellar find fine geopark grained horizontal hvol hvolsvapara hvolsvöllur iceland irish joined katla land likely llur lower manmade more most originated part prograding rather showing south strata suadeg that there they three tillite translates two upper upperhvol urland which