Bd. III: 2) CONTRIBUTIONS TO THE GEOLOGY OF THE FALKLAND ISLANDS. 
29 
/;) Bed of beach-shingle. Most of the pebbles are small, o ,02 0)05 
diam., though also large, well rounded blocks, 0,4 m. in length, were 
noticed 0,6 m. 
<r) Clay with small stones 0,15 — 0,3 » 
r/) Bed of edged, irregular blocks, plates and smaller stones cemented 
by stony clay of the same type as bed c 0,9 » 
It is evident that the water-worn surface of the rock as well as the shingle-bed 
originate from a time when the land was a little more submerged than it is to-day. 
The stony clay together with the superposed boulder-bed have evidently moved 
down the slope as a sheet-flood of flowing soil. The same section could be traced 
along the beach for a distance of 158 m., which is the minimum width of the out- 
flow. In one place the clay-bed had a thickness of 0,4 m. In some places it was 
quite crowded with small (o,oi — 0,03 m.) edged stones. 
The soil-flow which placed the boulder-bed upon the shingles must be later 
than the last upheaval of the land. As will be proved in the following chapter, 
the large stone-riv^ers are most probabl}^ much older. 
Changes in the level of the islands. 
The coast-line of the two large islands is deeply indented by numerous bays, 
which are in general narrow and often branch repeatedly towards the interior. 
Fig. 13. Submerged river-valley. Double Creek. 
