Thou by the Indian Ganges' side
Shouldst rubies find; I by the tide
Of Humber would complain
The Ganges in India are where tea and spices come from, so desirable to Marvell, who is miserable in Humberside. Humberside is a somewhat boring place in the Northeast of England. By contrast, the beautiful, mysterious Ganges seem very appealing. He is complimenting her; she is unique to him in a desirable way. She is the only person who fulfills the qualification in his vicinity.
To help improve the meaning of these lyrics, visit "To His Coy Mistress" by Andrew Marvell and leave a comment on the lyrics box