Joe's got a bit of a point there tigerbelle.
I'm afraid that parish records in Morvern don't start until 1804, and what's more a quick check of birth and marriage records in igi suggests that you'd have more luck looking for the marriage and children of Hugh McEachern and Mary Stewart. Maybe just a typo but I think that must be worth checking out. I've also read online that the Morvern records were poorly (and not completely) transcribed by the IGI researchers - so ScotlandsPeople.com may be the way forward.
There is an excellent book on Morvern at that time which describes all the settlements, and will point you towards local estate records that may be useful. Knock was a settlement near what is now the village of Lochaline. Ardtornish, at that time, would point to the land on the opposite side of Lochaline (ie on the other side of the loch itself).
The book's called "Morvern Transformed" by Philip Gaskell. Although it's out of print, it's a bit of a classic and easily obtainable secondhand through the Amazon or Abebooks websites. I'd normally say there isn't much to choose between the first and second editions unless you are interested in the big houses - but looking at my own copy of the second edition, the picture on the front cover is "Spinners, Knock, late nineteenth century". I don't know what's on the front cover of the first edition, but in your shoes I'd obviously start with the second edition (which is a paperback, published 1980, reprinted 1996).
Alistair
