I first heard about the Marshalls on an old family tree which my Mum did at school. There are people today as far away as South Africa who carry the name Marshall in their name, though they have probably forgotten why. These folks were farmers in Bodmin, near cold and shivery Bodmin Moor.
Look out for Ambrose Coviello the pianist, James Scott the stonemason and the master dyers Henry Lowry and John Hugo.