the story as told in the silmarillion ( p. 243 ) is somewhat fuller in its account of the escape of the fugitives from the city and the ambush in the eagles ' cleft ( there called cirith thoronath ) than in that of the assault and sack itself , but only in one point are the two narratives actually at variance -- as already noticed , the eagles ' cleft was afterwards moved from the southern parts of the encircling mountains to the northern , and idril 's tunnel led north from the city ( the comment is made that it was not thought 'that any fugitives would take a path towards the north and the highest parts of the mountains and the nighest to angband ' ) .