Are you sure they were from UK and not Northern Ireland?
I am a Philadelphia Morell. Name was spelled as Murrell before 1790s in Northern Ireland.
I am of the Samuel Morell (1824) and Hannah Evans Morell Clan from Moneydig Ireland. His father John (Murrell) Morell had a brother James (Murrell) Morell and also brothers Samuel and Nathaniel who also resided in Ballyquin, Garvagh, Moneydig, Lisachrin, and Limvady. Today Ballyquin, Lisachrin, and Moneydig are more know as roads or crossings etc... than towns.