"The usual belief is that Samuel Mothershead who embarked from London, ENG to VA in 1652 is the immigrant ancestor. "The Mottersheads were in Chester Co, ENG as early as the 12th century. "The Mothershead Family compiled by Marie Ray Davis.
There are still members of the Mothershead family in England. I can't get the story right, but there is a place in England related to the family name. the 'Head' part come from the head of a River.