133Gwynn, Edward. Poems from the Dindshenchas: Text, Translations and Vocabulary. Royal Irish Academy, 1900, pp. 21-3. Read online here.

The confusion regarding the well Nemnach may have been due to these, seemingly contradictory, verses:

Temair, whence Temair Breg is named,
Rampart of Tea wife of the son of Miled,
Nemnach is east of it, a stream through the glen
on which Cormac set the first mill...

The Caprach of Cormac is in the Rath of the Kings;
eastward from the Rath of the Kings (that is the truth of it)
is the Well of the Numbering of the Clans,
which is called by the three names...

Another source discusses St. Patrick's Well: "Poll tocair na tuiliche; meaning ‘Trial by Ordeal.' There is a medieval manuscript that talks about entering the waters and coming up again: if you had a black spot you were guilty and if you were spotless you were innocent." (Adomnán. "Well of the White Cow, Tara Hill." Ireland's Holy Wells, 14 Oct. 2011, irelandsholywells.blogspot.com/2011/10/well-of-white-cow-tara-hill.html.)

Another online source is here.