On what peninsula is the most important work of Francis William Deas ?
Francis William Deas:  His most important work was probably the restoration of Castle Toward. Castle Toward: Castle Toward (Scottish Gaelic: "Caisteal an Toll Àird" ) is a nineteenth-century country house on the southern tip of the Cowal peninsula, overlooking Rothesay Bay in Argyll and Bute on the west-coast of Scotland.
the Cowal peninsula