34 DR T. J. JEHU ON 



of a stiff bluish clay which is laminated. This can be traced continuously for a 

 considerable distance, but eventually it comes down to the level of the beach and dis- 

 appears. As we pass nearer the middle of the bay laminations appear near the top of 

 the cliff. The cliff face in this region is not so steep, and considerable slipping has 

 taken place so as to form a sort of under-cliff with a rough slope above. The top of the 

 cliff is here formed of the Upper Boulder Clay, which is yellowish in colour and some- 

 what sandy, and has a thickness of 12 to 20 feet. Where landslips have occurred they 

 have given rise to a lamination or stratification in all the deposits, the beds dipping 

 inland at a high angle. At one place about 1|- miles from the west end of the bay, a 

 bed of peat 1 8 inches thick was observed near the base dipping inland at an angle of 

 about 35°. It could be traced for a horizontal distance of 20 yards, and was resting on 

 boulder clay and overlain by sandy material and this again by boulder clay. The peat 

 contained reeds or sedge and was full of land-shells, such as Helix. It had evidently 

 slipped from the surface and been in turn covered by further landslips. 



A little to the east of the middle of the bay there is a good exposure of the Upper 

 Boulder Clay. The cliff is here 80 to 90 feet high, and the upper 25 feet consist of 

 rubbly clay immediately overlying the Lower Boulder Clay. This dies out when traced 

 laterally. Further east fine yellow sand is seen near the top of the cliff. The cliff 

 becomes lower as we travel towards Mynydd Cilan, and the Intermediate Sands and 

 Gravels become more prominent. Where the succession is most complete we have a 

 section as follows : — 



5. Soil and Blown Sand. 



4. Upper Boulder Clay, weathered and yellowish in colour, stiff in places, but often 



becoming sandy and pebbly or even rubbly. 



3. Fine yellow siliceous sand becoming somewhat clayey in its lower part. 



2. Laminated greyish-blue stoneless clay becoming somewhat sandy in places, and 



distinctly marked off from 1 . 



1. The massive Lower Boulder Clay which forms the base of the cliff and the bottom 



of which is not reached. 



Near the extreme east end of the bay the gravels of the Intermediate series come down 

 to the base of the cliff, but the Lower Boulder Clay is exposed on the foreshore below. 



At a short distance from this end peat appears in the upper part of the low cliff. 

 This peat can only be traced for a horizontal distance of about 1 00 feet. The section 

 here is as follows : — 



5. Blown sand — 5 feet. 



4. Peat— 3 1 feet. 



3. Stiff blue peaty clay — 2 feet. 



2. Greyish-blue somewhat sandy clay, pebbly in places — I foot. 



1.. Stiff Boulder Clay with a tendency to lamination and comparatively stoneless. 

 (This rests on the beach and its bottom is not reached.) 



i 



