Hi Brit staying on the Co Down Houston, I hope you tried Ros Davies website, my last suggestion is try family trees etc that appear in Blackwood Family history manuscript tree collection in the LinenHall library, Belfast. The collection is strong in Co Down families. As you live overseas as many do, then I suggest you ask them for photocopying estimates if they think your knowledge relevant and be prepared to pay the extra for post and packing. However if the material is really relevant when you get it, I suggest a further donation to this unique library that is always needing extra funds. Linen Hall Library,17 Donegall Square North, Belfast BT15GB, Northern Ireland, Email:info[at]linenhall.com or just go onto their website for contact details. .
The volume references are
HOUSTON in Vol 3 p126 Blakiston {This Blakiston addition means a major marriage], Vol 7p175, Vol 23T {The T means transcripted elsewhere and would have meant mr blackwood did another tree in a higher volume number, but that is missing.
Hoping this is widens or narrows the information for your quest.
JimG
Hi houston 03, if you start your own topic, I hope you will have used askireland Griffiths valuation for the 160 plus Houston homesteads that existed in 1858 in Co Tyrone goos luck Jimg