Earth hath not anything to show more fair:
Dull would he be of soul who could pass by
A sight so touching in its majesty:
This City now doth, like a garment, wear
The beauty of the morning; silent, bare,
Ships, towers, domes, theatres and temples lie
Open unto the fields, and to the sky;
All bright and glittering in the smokeless air.
Never did sun more beautifully steep
In his first splendor, valley, rock, or hill;
Ne'er saw I, never felt, a calm so deep!
The river glideth at his own sweet will:
Dear God! The very houses seem asleep;
Steep means to drop into (like a tea-bag into a cup)—Wordsworth proclaims that the sun has never before shone as beautifully. 
 The ‘valley, rock, or hill’ makes up another  lexical field , this time of the countryside. Wordsworth is saying that the sun bathes the city as beautifully as it does the countryside.
Composed upon Westminster Bridge September 3 1802