§ Of the Coming of the Elves and the Captivity of Melkor The Silmarillion

Long and slow was the march of the Eldar into the west, for the leagues of Middle-earth were uncounted, and weary and pathless. Nor did the Eldar desire to hasten, for they were filled with wonder at all that they saw, and by many lands and rivers they wished to abide; and though all were yet willing to wander, many feared rather their journey's end than hoped for it Therefore whenever Oromë departed, having at times other matters to heed, they halted and went forward no more, until he returned to guide them. And it came to pass after many years of journeying in this manner that the Eldar took their course through a forest, and they came to a great river, wider than any they had yet seen; and beyond it were mountains whose sharp horns seemed to pierce the realm of the stars. This river, it is said, was even the river which was after called Anduin the Great, and was ever the frontier of the west-lands of Middle-earth. But the mountains were the Hithaeglir, the Towers of Mist upon the borders of Eriador; yet they were taller and more terrible in those days, and were reared by Melkor to hinder the riding of Oromë. Now the Teleri abode long on the east bank of that river and wished to remain there, but the Vanyar and me Noldor passed over it, and Oromë led them into the passes of the mountains. And when Oromë was gone forward the Teleri looked upon the shadowy heights and were afraid.