This final letter is usually called Zee.

1

1797.  Zounds, I’m safe at zigzag zee.—End of alliterative verses in the Farmer’s Museum: Gazette of the U.S., Phila., April 7.

2

[1830.  I will teach you your alphabet from A to Zed and from Zed back again to A. Given as a Southernism.—Mass. Spy, July 28: from the N.Y. Constellation.]

3

1883.  The use of Zee is noticed by E. A. Freeman.—‘Impressions of the U.S.,’ pp. 83–4.

4