A lot of Trefethens intermarried with Amazeens over the year and since it too is a unique name we've gathered info of Amazeens assuming it'll help someday. I'd be happy to check the Trefethen Roundtable archives on any specific Amazeen. Also an excellent Trefethen site exsists at
which has info on Amazeen relatives. Also those Jones mentioned here are Trefethen relatives too if I remember correctly.
as well was I have a draft of the Cornville/Exeter/Dexter/etc. Trefethens that include several hundred names many not on thr official site yet. We have lots of loose ends were looking for as well as lines we'd love to find.
Please visit the site and share any scrap of info you have. The site is well indexed so give it a try.