re book "Joseph Ledlie and William Moody, early Pittsburgh residents" by Ledlie Irwin Laughlin. It mentions John Houston Jnr., John Houston. In 1691 Capt. John Houston of Castlestewart, co. Tyrone, Ireland, leased property to Pettigrew, Wallwoods and Ledely. In 1698 property was divided, Ledely taking Carnan, Arboe Parish, co. Tyrone.William Carley ejected the Ledlies. James Pettigrew as mortgage-holder joined the Ledlies in suit. Plaintiff was Patrick O'Devillen.
The Ledlies may have won the case as in 1728, PRONI file D847/6/9A/1, there were William Ledlie and Gilbert Ledlie, sons of John (of ?) Carnan.
In 1737 there was another file D847/6/3/2, naming Ledlie, 3rd son of Gilbert John Ledlie, Carnan, Arboe Parish.
In 1695, PRONI file D1618/2/7, there was a townland of Carn, part of the manor of Castle Stewart.
About 1672 - 1683 William Houston purchased part of the Manor of Castlestewart from Lord Howard, Earl of Suffolk who m. the daughter of Stewart.I am not sure if John Houston snr was brother of William Houston or his son.
I would be very grateful if you would you please look in your book for the full extract on the Houstons. Thankyou.