Definition of "wellhead"

Leaue the troubled streames,And liue as Thriuers doe at the Well head.

1607, George Chapman, Bussy D'Ambois‎, London: William Aspley, act I, scene 1, page 3

It is a singular circumstance, that within a quarter of a mile of the well-head of the Wye, arises the Severn.

1789, William Gilpin, Observations on the River Wye‎, London: R. Blamire, Section 6, p. 74

We set forth accordingly by this itinerary; and for the best part of three nights travelled on eerie mountains and among the well-heads of wild rivers; [...]

1886 May 1 – July 31, Robert Louis Stevenson, “The Flight in the Heather: The Quarrel”, in Kidnapped, being Memoirs of the Adventures of David Balfour in the Year 1751: […], London, Paris: Cassell & Company, published 1886, pages 239–240

[H]e likened was to a welhed / Of euill words, and wicked ſclaunders by him ſhed.

1596, Edmund Spenser, “Book V, Canto IX”, in The Faerie Queene. […], part II (books IV–VI), London: […] [Richard Field] for William Ponsonby, stanza 26, page 303

[...] a bull was not merely a stud animal worth so much, due to go to the butcher in a little while. It was a vast wonder-beast, a well-head of the great, furnace-like passion that makes the worlds roll and the sun surge up [...]

1932, D. H. Lawrence, “Painted Tombs of Tarquinia”, in Etruscan Places, New York: Viking, published 1957, page 113