What legal innovations in 17th century Virginia contrasted with English common law?
England had a history of representative government and "common law" starting with the Magna Carta in 1215, which began to limit the power of the monarchy. Other nations in Europe, notably France and Spain, never had such restrictions placed upon the monarchy and thus remained as absolute monarchies for centuries.
The means by which the power of the monarchy was limited in England was by restricting the power to create law; that instead was the realm of legislative assemblies. Parliament embodied the legislative power of government, while the monarch continued to embody the executive power.
This separation of powers transplanted to the New World in the colony of Virginia, starting in 1619 with the establishment of the House of Burgesses. It, like Parliament back in London, was the legislative branch of governance for the colony.
As more colonies in the New World became established, they, in turn, also implemented legislative bodies, following Virginia's example.