Glen Clova in Angus is one of the most beautiful places I've visited. Sadly it rained so we didn't get to climb up to Loch Brandy but that gave me an excuse to look at the drumlins. Drumlins are formed by material deposited by glaciers. I had thought that they were due to galciers melting but some theories seem to favour deposition due to melt water under the glacier. If it is water depositing the particles, you'd expect the bigger lumps nearer the bottom and the finer grains to be suspended for longer. That would seem to tie in with the undisturbed sections of this excavation.