234 
Liver Rot of Sheep 
II. The coastal plateau consists of rock ancl boulder clay. The 
clay is usually exposed and rarely covered with peat. 
III. The fall line, which is intermediate. Here the boulder clay 
generally follows the valleys, and is usually covered with a thin layer 
of peat. Much of this is readily cut through by small streams. 
Machyr/JLth 
r~Sr - Up/ands.) P ' c 
South-East Reg/on 
© Rounja// Sta.t/o/25 
Fig. 1. Map of the Aberystwyth Area, Wales. 
The Dyfi Flats form a distinct type consisting largely of peat but 
with a few well defined tracts of tenacious clay (alluvium). 
Two areas are of special significance, namely, Devils Bridge, 
Rhos-y-gell; and South of Yspytty Ystwyth as far as Pontrhydfendigaid. 
These large districts are floored entirely by boulder clay and are ill 
drained. 
