Here are some examples of erosion features you could identify on a map.
A good start is to look for name evidence.
On this extract, the term 'point' (meaning headland) appears at Warren Point 667421, 'cliff' at West Cliff 692383 and 'cove', indicating where erosion has produced a small bay, at Redrot Cove at 668394.
The shape of the coast is also a good indicator.
Smaller headlands like Warren Point and Thurlestone Rock 675414 enclose sandy bays like the ones at 676416 on the map.
Off the headland there are small islands - Mew Stone 725359 and Little Mew Stone, 727358. These will be former parts of the headland now worn down to be stacks or stumps. Burgh Island was separated from the mainland by erosion.
Symbol evidence is also important and we see the symbols for cliffs at 688383 and steep slopes at 704368. Around here, contour lines appear to run into the sea, indicating the height of the cliffs at that point.