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Silmarillion fin ch 11 / Home 10 Annales d'Aman §181 : 

And in that time also, which songs call Nurtalë Valinóreva, the Hiding of Valinor, the Enchanted Isles were set, and all the seas about them were filled with shadows and bewilderment. And these isles were strung as a net in the Shadowy Seas from the north to the south, before Tol Eressëa, the Lonely Isle, is reached by one sailing west. Hardly might any vessel pass between them, for in the dangerous sounds the waves sighed for ever upon dark rocks shrouded in mist. And in the twilight a great weariness came upon mariners and a loathing of the sea; but all that ever set foot upon the islands were there entrapped, and slept until the Change of the World. Thus it was that as Mandos foretold to them in Araman the Blessed Realm was shut against the Noldor; and of the many messengers that in after days sailed into the West none came ever to Valinor - save one only: the mightiest mariner of song.

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Silmarillion ch 24 : 

And the wise have said that it was by reason of the power of that holy jewel that [Eärendil & Elwing] came in time to waters that no vessels save those of the Teleri had known; and they came to the Enchanted Isles and escaped their enchantment; and they came into the Shadowy Seas and passed their shadows.

Citation :$177 Therefore by the coming and going of Anar the Valar reckoned the days thereafter until the Change of the World. 

Citation : 'The Doom of the World,' they said, 'One alone can change who made it. And were you so to voyage that escaping all deceits and snares you came indeed to Aman, the Blessed Realm, little would it profit you.