Macalla, meaning Echo, is a revival of Gaelic orthography of the 1800s. It is based on the type used in Transactions of the Ossianic Society, 1858. That unidentified typeface shows marked similarities to Watts in particular (1818) and an American redrawing for the Irish Echo (1881). There are some differences though, particularly in the lowercase “d” and “e”.
As well as Watts and the Irish Echo, similar historical fonts were created by Barlow, Christie, Fry and Figgins (Dermot McGuinne, Irish Type Design 1992). They are characterised by unusual uppercase A and M glyphs, which are almost blackletter in appearance.
As per the original, it's a single weight with no italics.
Click here for a type specimen and download links.