Devensian till at Madoc's Haven

View southwards across Madoc's Haven towards Druidston in the middle distance.  Virtually the while of this cliffline is capped by thin Devensian till.  Notice the large recent rockfall beneath the nearest cliff.  Note also the bevel on the clifftops.  I think this is an ancient feature, since the fresh till rests on the bevelled slope.

Madoc's Haven is an attractive and rather inaccessible bay (except at extreme low tide) between Druidston and Nolton Haven.  I walked along the clifftop yesterday, and was not at all surprised that there is fresh till capping the cliff almost continuously, over a distance of more than 1 km.

Wherever one can get close enough to take a look, the till layer is relatively thin (seldom over 2m thick) but quite undisturbed.  In places, there are traces of slope breccia beneath it, but there is never ant slope breccia above it.  It occurs up to the ground surface, with its top incorporated into  a layer of sandy loam and soil.  There is no upper slope breccia even where there is a modest slope leading down to the cliff edge.

Fresh till less than 50 cms thick, resting on broken bedrock, in a small stream valley crossed by the coast path, north of Druidston.  Above the till we see 50-60 cms of sandy loam.  Above that is the modern soil.  Intriguingly, there is a high percentage of rounded and sub-rounded pebbles in this till.

A fine exposure of till containing large striated erratics (many of them igneous) exposed in a stream cutting at the northern end of Madoc's Haven.   This till is over 2m thick, and is capped by sandy loam and soil.   Not far away there is another clifftop exposure  in which we can see 1.5 m of pseudo-stratified slope breccia beneath the till, but no slope breccia above. 

Heavily weathered and abraded igneous erratic near the exposure shown above.

I was struck, in examining these multiple exposures, that they look virtually the same as the clifftop exposures on the south coast of Pembrokeshire which I have featured in other posts.  The conclusion is inescapable -- both coastlines have been affected by encroaching glacier ice relatively recently -- in the Late Devensian.  All the signs are that this encroachment occurred around 26,000 years ago.