Revetting : that is,worked stones so placed as to support a steep bank.Curiouser and curiouser, said Alice.Now, immediately downstream of this point,is a steep bank,about 30 ft. high.It has this rivulet running down it's upstream side.It appears to be revetted up to the flattish field above.Why ?Just downstream is a wide cleft, at a steep angle down to the riverbank, forming a promontory,with good views up and down the river.A defensive strong point by a river crossing ??