Final answer:
King James I was referring to the tobacco industry, which became highly profitable in the Chesapeake colonies after initial efforts to find gold and silver.
Step-by-step explanation:
When King James I was referring to a profitable colonial industry, he was likely referencing the growing of tobacco, which was the most lucrative product of the Chesapeake colonies. Although the Virginia Company initially hoped to find gold and silver, it was the cultivation of tobacco that eventually brought success and wealth, particularly after Jamestown began exporting tobacco to Europe in 1614. Despite England's mercantilist policies that valued the accumulation of gold and silver, tobacco became the precious commodity that contributed significantly to the economic growth of the colonies and increased profits for the English treasury.