Thanks, Roslyn, for copying part of the article by A. McKerral.
A few comments on his etymologies, however:
> "baile, a word cognate to the Latin vallum and ballium and
> probably meaning originally the same thing--a fortified place.
That's certainly not generally accepted. As I understand it, "ballium"
is a Medieval Latin word formed on OF "baille" (> Eng. "bailey"), which
in turn comes from the plural of Lat. "baculum".
> "This is pit, or the pett of the Book of the
> Deer. Some authorities regard it as the northern form of the Gaelic buth,
> meaning nowadays a shop but signifying in ancient times a dwelling of some
Scottish Gaelic "býth" is a borrowing from ON or English, and "pit" of
course much antedates the arrival of those languages on the scene.
> "A form of pit with the Gaelic genitive an is Pit-an, becoming Fin in
> names like Findhorn, Finlaggan.
That seems improbable. In any case, placenames in Fin- generally come
from "fionn-" (bright, white).